MCT8-specific thyroid hormone cell transporter deficiency (THCT deficiency) is an inherited disorder that is characterized by severe mental retardation, an impaired ability to speak, diminished muscle tone (hypotonia), and/or movement abnormalities. With the exception of poor muscle tone, most affected infants appear to develop normally during the first months of life. However, by about two months of age, affected infants may seem  Read More

MCT8-specific thyroid hormone cell transporter deficiency (THCT deficiency) is an inherited disorder that is characterized by severe mental retardation, an impaired ability to speak, diminished muscle tone (hypotonia), and/or movement abnormalities. With the exception of poor muscle tone, most affected infants appear to develop normally during the first months of life. However, by about two months of age, affected infants may seem  Read More

Alpers disease is a progressive neurologic disorder that begins during childhood and is complicated in many instances by serious liver disease. Symptoms include increased muscle tone with exaggerated reflexes (spasticity), seizures, and loss of cognitive ability (dementia).  Read More

Froehlich syndrome is a constellation of endocrine abnormalities believed to result from damage to the hypothalamus, a part of the brain where certain functions such as sleep cycles and body temperature are regulated. Froehlich syndrome appears to be acquired while certain other disorders that resemble it, such as Prader-Willi syndrome, are genetic. This syndrome appears to affect males mostly. The more obvious and frequently encou  Read More

Balo Disease is a rare and progressive variant of multiple sclerosis. It usually first appears in adulthood, but childhood cases have also been reported. While multiple sclerosis typically is a disease that waxes and wanes, Balo Disease is different in that it tends to be rapidly progressive. Symptoms may include headache, seizures, gradual paralysis, involuntary muscle spasms, and cognitive loss. The alternative names for Balo Disease, concen  Read More

Blue rubber bleb nevus syndrome (BRBNS) is a rare blood vessel (vascular) disorder that affects the skin and internal organs of the body. Multiple distinctive skin lesions are usually characteristic of this disorder and are often present at birth or present during early childhood. Lesions in the gastrointestinal tract frequently become apparent during childhood or early adulthood. The lesions are multifocal venous malformations, resulting from  Read More

Binswanger's disease (BD), also called subcortical vascular dementia, is a type of dementia caused by widespread, microscopic areas of damage to the deep layers of white matter in the brain. The damage is the result of the thickening and narrowing (atherosclerosis) of arteries that feed the subcortical areas of the brain. Atherosclerosis (commonly known as "hardening of the arteries") is a systemic process that affects blood vessels throughout  Read More

Benign essential blepharospasm (BEB) is a rare neurological disorder in which affected individuals experience involuntary muscle spasms and contractions of the muscles around the eyes. These spasms come and go (intermittent). Symptoms may begin as eye twitching, blinking and/or irritation. Eventually, BEB causes involuntary closure of the eyes. The exact cause of BEB is unknown. The disorder is one of a group of disorders collectively known as  Read More

Signs and symptoms of paraneoplastic syndromes of the nervous system can develop relatively quickly, often over days to weeks. Signs and symptoms of paraneoplastic syndromes of the nervous system often begin even before a cancer is diagnosed. Signs and symptoms vary depending on the body part being injured, and may include: Difficulty walking Difficulty maintaining balance Loss of muscle coordination  Read More

Canavan disease is rare genetic neurological disorder characterized by the spongy degeneration of the white matter in the brain. Affected infants may appear normal at birth, but usually develop symptoms between 3-6 months of age. Symptoms may include an abnormally large head (macrocephaly), lack of head control, severely diminished muscle tone resulting in "floppiness," and delays in reaching developmental milestones such as independent sittin  Read More

Canavan disease is rare genetic neurological disorder characterized by the spongy degeneration of the white matter in the brain. Affected infants may appear normal at birth, but usually develop symptoms between 3-6 months of age. Symptoms may include an abnormally large head (macrocephaly), lack of head control, severely diminished muscle tone resulting in "floppiness," and delays in reaching developmental milestones such as independent sittin  Read More

Canavan disease is rare genetic neurological disorder characterized by the spongy degeneration of the white matter in the brain. Affected infants may appear normal at birth, but usually develop symptoms between 3-6 months of age. Symptoms may include an abnormally large head (macrocephaly), lack of head control, severely diminished muscle tone resulting in "floppiness," and delays in reaching developmental milestones such as independent sittin  Read More

Coffin-Lowry syndrome is a rare genetic disorder characterized by mental retardation; abnormalities of the head and facial (craniofacial) area; large, soft hands with short, thin (tapered) fingers; short stature; and/or various skeletal abnormalities. Characteristic facial features may include an underdeveloped upper jawbone (maxillary hypoplasia), an abnormally prominent brow, downslanting eyelid folds (palpebral fissures), widely spaced eyes  Read More

Cerebro-oculo-facio-skeletal (COFS) syndrome is a genetic degenerative disorder of the brain and spinal cord that begins before birth. The disorder is characterized by growth failure at birth and little or no neurological development, structural abnormalities of the eye and fixed bending of the spine and joints. Abnormalities of the skull, face, limbs and other parts of the body may also occur. COFS syndrome is inherited as an autosomal recess  Read More

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and behavior. The 4th ventricle is a space around the cerebellum that channels fluid from inside to around the outside of the brain. DWM is characterized by underdevelopment (small size and abnormal positi  Read More

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and behavior. The 4th ventricle is a space around the cerebellum that channels fluid from inside to around the outside of the brain. DWM is characterized by underdevelopment (small size and abnormal positi  Read More

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and behavior. The 4th ventricle is a space around the cerebellum that channels fluid from inside to around the outside of the brain. DWM is characterized by underdevelopment (small size and abnormal positi  Read More

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and behavior. The 4th ventricle is a space around the cerebellum that channels fluid from inside to around the outside of the brain. DWM is characterized by underdevelopment (small size and abnormal positi  Read More

Dejerine-Sottas disease is an inherited neurological disorder that progressively affects mobility. Peripheral nerves become enlarged or thickened leading to muscle weakness. Progress of the disorder is irregular and often accompanied by pain, weakness, numbness, and a tingling, prickling or burning sensation in the legs. Many people with Dejerine-Sottas disease continue to lead active lives. Most neurologists now consider this diso  Read More

Familial dysautonomia is a rare genetic disorder of the autonomic nervous system (ANS) that primarily affects people of Eastern European Jewish heritage. It is characterized by diminished sensitivity to pain, lack of overflow tearing in the eyes, a decrease in the number of knob-like projections that cover the tongue (fungiform papillae), unusual fluctuations of body temperature, and unstable blood pressure. Symptoms of this disorder are appar  Read More

Eales Disease is a rare disorder of sight that appears as an inflammation and white haze around the outercoat of the veins in the retina. The disorder is most prevalent among young males and normally affects both eyes. Usually, vision is suddenly blurred because the clear jelly that fills the eyeball behind the lens of the eye seeps out (vitreous hemorrhaging).  Read More

Proteus syndrome is a rare disorder characterized by overgrowth of various tissues of the body. The cause of the disorder is a mosaic mutation in a gene called AKT1. Disproportionate, asymmetric overgrowth occurs in a mosaic pattern (i.e., a random "patchy" pattern of affected and unaffected areas). Affected individuals may experience a wide variety of complications that may include progressive skeletal malformations, benign and malignant tumo  Read More

The hereditary ataxias are a group of neurological disorders (ataxias) of varying degrees of rarity that are inherited, in contrast to a related group of neurological disorders that are acquired through accidents, injuries, or other external agents. The hereditary ataxias are characterized by degenerative changes in the brain and spinal cord that lead to an awkward, uncoordinated walk (gait) accompanied often by poor eye-hand coordination and  Read More

Erythromelalgia is a rare condition that primarily affects the feet and, less commonly, the hands (extremities). It is characterized by intense, burning pain of affected extremities, severe redness (erythema), and increased skin temperature that may be episodic or almost continuous in nature. (The prefix "erythro-" denotes redness, "mel-" is a combining form meaning limb or limbs, and the suffix "-algia" indicates pain.) Although erythromelalg  Read More

The hereditary sensory neuropathies (HSN) include 4-6 similar but distinct inherited degenerative disorders of the nervous system (neurodegenerative) that frequently progress to loss of feeling, especially in the hands and feet. The classification of these diseases is complicated, and sometimes a source of disagreement among the experts. Hereditary sensory neuropathy type IV (HSN4) is a rare genetic disorder characterized by the lo  Read More

Familial lipoprotein lipase (LPL) deficiency is a rare genetic metabolic disorder characterized by a deficiency of the enzyme lipoprotein lipase. The deficiency of this enzyme prevents affected individuals from properly digesting certain fats and results in a massive accumulation of fatty droplets called chylomicrons in the circulation (chylomicronemia) and consequently also an increase in the plasma concentration of fatty substances called tr  Read More

Floating-Harbor syndrome (FHS) is an extremely rare disorder characterized by short stature, delayed language skills, and a triangular shaped face. A broad nose, deep-set eyes and a wide mouth with thin lips give an affected individual a distinct appearance. FHS was named after the hospitals at which the first two cases were seen: the Boston Floating Hospital and Harbor General Hospital in California. The cause of this disorder is not known.  Read More

MERRF (Myoclonus Epilepsy with Ragged-Red Fibers) syndrome is an extremely rare disorder that begins in childhood and affects the nervous system and skeletal muscle as well as other body systems. The distinguishing feature in MERRF is myoclonus, consisting of sudden, brief, jerking spasms that can affect the arms and legs or the entire body. In addition, individuals with MERRF syndrome may have muscle weakness (myopathy), an impaired ability t  Read More

Fukuyama type congenital muscular dystrophy (FCMD) is one of several forms of a rare type of muscular dystrophy known as congenital muscular dystrophy. It is inherited as an autosomal recessive trait. Symptoms of this disorder are apparent at birth and progress slowly. In addition to general muscle weakness and deformities of the joints (contractures), FCMD is often accompanied by seizures, mental retardation and speech problems. This disorder  Read More

Galloway-Mowat Syndrome, which is also known as Microcephaly-Hiatal Hernia-Nephrotic Syndrome, is an extremely rare genetic disorder that is characterized by a variety of physical and developmental abnormalities. Physical features may include an unusually small head (microcephaly) and additional abnormalities of the head and facial (craniofacial) area; damage to clusters of capillaries in the kidneys (focal glomerulosclerosis and/or diffuse me  Read More

Galloway-Mowat Syndrome, which is also known as Microcephaly-Hiatal Hernia-Nephrotic Syndrome, is an extremely rare genetic disorder that is characterized by a variety of physical and developmental abnormalities. Physical features may include an unusually small head (microcephaly) and additional abnormalities of the head and facial (craniofacial) area; damage to clusters of capillaries in the kidneys (focal glomerulosclerosis and/or diffuse me  Read More

Pseudo-Hurler polydystrophy (mucolipidosis type III) is a rare genetic metabolic disorder characterized by a defective enzyme known as UPD-N-acetylglucosamine-1-phosphotransferase. This defective enzyme ultimately results in the accumulation of certain complex carbohydrates (mucopolysaccharides) and fatty substances (mucolipids) in various tissues of the body. The symptoms of this disorder are similar, but less severe than those of I-cell dise  Read More

Giant axonal neuropathy is a rare neuropathy that severely affects the peripheral as well as the central nervous system. The first symptoms appear in early childhood. This disorder is characterized by abnormalities in the peripheral and central nervous systems including low muscle tone (hypotonia), muscle weakness, decreased reflexes, impaired muscle coordination (ataxia), seizures and intellectual disability. Pale, tightly curled hair is freq  Read More

Glutaricaciduria I (GA-I) is a rare hereditary metabolic disorder, caused by a deficiency of the enzyme glutaryl-CoA dehydrogenase. One of a group of disorders known as "organic acidemias," it is characterized by an enlarged head (macrocephaly), decreased muscle tone (hypotonia), vomiting, and excess acid in the blood. Affected individuals may also have involuntary movements of the trunk and limbs (dystonia or athetosis) and mental retardation  Read More

Hajdu-Cheney syndrome (HCS) is a rare, heritable disorder of connective tissue; only about 50 cases have been reported in the medical literature. The breakdown of bone (osteolysis), especially the outermost bones of the fingers and toes (acroosteolysis), is a major characteristic of HCS. In addition, patients with HCS frequently have skull deformities, short stature, joint laxity, reduction of bone mass (osteoporosis) and other sig  Read More

Vogt-Koyanagi-Harada disease is a rare disorder of unknown origin that affects many body systems, including as the eyes, ears, skin, and the covering of the brain and spinal cord (the meninges). The most noticeable symptom is a rapid loss of vision. There may also be neurological signs such as severe headache, vertigo, nausea, and drowsiness. Loss of hearing, and loss of hair (alopecia) and skin color may occur along, with whitening (loss of p  Read More

Roussy-Levy Syndrome, also known as hereditary areflexic dystasia, is a rare genetic neuromuscular disorder that typically becomes apparent during early childhood. The disorder is characterized by incoordination, poor judgment of movements (sensory ataxia), and absence of reflexes (areflexia) of the lower legs and, eventually, the hands; weakness and degeneration (atrophy) of muscles of the lower legs; abnormally high arches of the feet with i  Read More

The hereditary sensory neuropathies (HSN) include 4-6 similar but distinct inherited degenerative disorders of the nervous system (neurodegenerative) that frequently progress to loss of feeling, especially in the hands and feet. The classification of these diseases is complicated, and sometimes a source of disagreement among the experts. Hereditary sensory neuropathy type IV (HSN4) is a rare genetic disorder characterized by the lo  Read More

Hereditary sensory and autonomic neuropathy type II (HSAN2) is a rare genetic disorder that usually begins in childhood by affecting the nerves that serve the lower legs and feet and the lower arms and hands. Symptoms start with inflamed fingers or toes, especially around the nails. Numbness and tingling sensations in the hands and feet may also occur. Eventually, affected individuals lose feeling (sensation) in the hands and feet. This sensor  Read More

Familial dysautonomia is a rare genetic disorder of the autonomic nervous system (ANS) that primarily affects people of Eastern European Jewish heritage. It is characterized by diminished sensitivity to pain, lack of overflow tearing in the eyes, a decrease in the number of knob-like projections that cover the tongue (fungiform papillae), unusual fluctuations of body temperature, and unstable blood pressure. Symptoms of this disorder are appar  Read More

Isovaleric Acidemia is a hereditary metabolic disorder. It is characterized by a deficiency of the enzyme isovaleryl CoA dehydrogenase. The disorder occurs in both an acute and a chronic intermittent form. In the acute form of Isovaleric Acidemia, vomiting, refusal to eat, and listlessness usually occur. With treatment and low protein diet, the disorder becomes chronically intermittent, and a nearly normal life is possible.  Read More

Machado-Joseph Disease (MJD-III), also called spinocerebellar ataxia type III, is a rare, inherited, ataxia (lack of muscular control) affecting the central nervous system and characterized by the slow degeneration of particular areas of the brain called the hindbrain. Patients with MJD may eventually become crippled and/or paralyzed but their intellect remains intact. The onset of symptoms of MJD varies from early teens to late adulthood.  Read More

Joubert syndrome is an autosomal recessive genetic disorder that affects the area of the brain that controls balance and coordination. This condition is characterized by a specific finding on an MRI called a "molar tooth sign" in which the cerebellar vermis of the brain is absent or underdeveloped and the brain stem is abnormal. The most common features of Joubert syndrome are lack of muscle control (ataxia), abnormal breathing patterns (hyper  Read More

Juberg-Marsidi syndrome is an extremely rare X-linked genetic disorder that is fully expressed in males only, and is apparent at birth (congenital) or during the first few weeks of life (neonatal period). Affected children exhibit severe mental retardation; delays in reaching developmental milestones (e.g., crawling, walking, etc.); muscle weakness; diminished muscle tone (hypotonia); and/or delayed bone growth as well as growth retardation, r  Read More

Kearns-Sayre syndrome (KSS) is a rare neuromuscular disorder characterized by three primary findings: progressive paralysis of certain eye muscles (chronic progressive external ophthalmoplegia [CPEO]); abnormal accumulation of colored (pigmented) material on the nerve-rich membrane lining the eyes (atypical retinitis pigmentosa), leading to chronic inflammation, progressive degeneration, and wearing away of certain eye structures (pigmentary d  Read More

Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder characterized by the gradual onset of muscle weakness, especially of the pelvic and thigh muscles. Approximately 60 percent of LEMS cases are associated with a small cell lung cancer (SCLC), and the onset of LEMS symptoms often precedes the detection of the cancer. The LEMS patients with cancer tend to be older and nearly always have a long history of smoking. In cases in w  Read More

Langerhans cell histiocytosis (LCH) is a spectrum of rare disorders characterized by overproduction (proliferation) and accumulation of a specific type of white blood cell (histiocyte) in the various tissues and organs of the body (lesions). The lesions may include certain distinctive Langerhans cells involved in certain immune responses, as well as other white blood cells (e.g.,lymphocytes, monocytes, eosinophils). Associated symptoms and fin  Read More

Langerhans cell histiocytosis (LCH) is a spectrum of rare disorders characterized by overproduction (proliferation) and accumulation of a specific type of white blood cell (histiocyte) in the various tissues and organs of the body (lesions). The lesions may include certain distinctive Langerhans cells involved in certain immune responses, as well as other white blood cells (e.g.,lymphocytes, monocytes, eosinophils). Associated symptoms and fin  Read More

Growth hormone insensitivity (GHI) is a group of extremely rare genetic disorders in which the body is unable to use the growth hormone that it produces. GHI can be caused by mutations in the growth hormone receptor (GHR) gene or mutations in genes involved in the action pathway within the cell after the growth hormone binds to its receptor, preventing the production of insulin-like growth factor (IGF-1), the substance responsible for the grow  Read More

Classical lissencephaly, also known as lissencephaly type I, is a brain malformation that may occur as an isolated abnormality (isolated lissencephaly sequence [ILS]) or in association with certain underlying syndromes (e.g., Miller-Dieker syndrome, Norman-Roberts syndrome). The condition is characterized by absence (agyria) or incomplete development (pachygyria) of the ridges or convolutions (gyri) of the outer region of the brain (cerebral c  Read More

Classical lissencephaly, also known as lissencephaly type I, is a brain malformation that may occur as an isolated abnormality (isolated lissencephaly sequence [ILS]) or in association with certain underlying syndromes (e.g., Miller-Dieker syndrome, Norman-Roberts syndrome). The condition is characterized by absence (agyria) or incomplete development (pachygyria) of the ridges or convolutions (gyri) of the outer region of the brain (cerebral c  Read More

Marcus Gunn phenomenon is a rare genetic disorder that is usually present at birth. It is characterized by the movement of one upper eyelid in a rapid rising motion each time the jaw moves. Other eye abnormalities and vision difficulties may also occur. The exact cause of this phenomenon is not known.  Read More

Marinesco-Sjogren syndrome (MSS) is a rare genetic disorder that affects multiple organ systems of the body. Common symptoms include difficulty coordinating voluntary movements due to degeneration (atrophy) of the cerebellum (cerebellar ataxia), clouding of the lenses of the eyes (cataracts), delays in the acquisition of skills requiring the coordination of muscular and mental activity (psychomotor development), diminished muscle tone (hypoton  Read More

Kearns-Sayre syndrome (KSS) is a rare neuromuscular disorder characterized by three primary findings: progressive paralysis of certain eye muscles (chronic progressive external ophthalmoplegia [CPEO]); abnormal accumulation of colored (pigmented) material on the nerve-rich membrane lining the eyes (atypical retinitis pigmentosa), leading to chronic inflammation, progressive degeneration, and wearing away of certain eye structures (pigmentary d  Read More

N-acetylglutamate synthetase (NAGS) deficiency is a rare genetic disorder characterized by complete or partial lack of the enzyme N-acetylglutamate synthetase (NAGS). NAGS is one of six enzymes that play a role in the break down and removal of nitrogen from the body, a process known as the urea cycle. The lack of the NAGS enzyme results in excessive accumulation of nitrogen, in the form of ammonia, in the blood (hyperammonemia). Excess ammonia  Read More

Wiedemann-Rautenstrauch syndrome (WRS), also known as neonatal progeroid syndrome, is a very rare genetic disorder characterized by an aged appearance at birth (old man look) growth delays before and after birth (prenatal and postnatal growth retardation), and deficiency or absence of the layer of fat under the skin (subcutaneous lipoatrophy). It is anticipated that most individuals with WRS have decreased life expectancy. There are few indivi  Read More

Niemann-Pick disease (NPD) is a group of rare inherited disorders of fat metabolism. At least five types of Niemann-Pick disease have been identified (NPD types A, B, C, D, and E). Symptoms of types A and B occur as a result of a deficiency of the enzyme acid sphingomyelinase (ASM), which is needed to break down sphingomyelin, a fatty substance found mostly in the brain and nervous system. This deficiency results in abnormal accumulation of ex  Read More

Oculocerebrocutaneous (OCC) syndrome, a rare genetic disorder, is apparent at birth (congenital). The disorder is characterized primarily by eye (ocular), brain (e.g., cerebral), and skin (cutaneous) malformations. For example, many affected infants have semisolid or fluid-filled swellings (cysts) within the cavities of the skull (orbits) that accommodate the eyeballs and associated structures. In most cases, the eye on the affected side or si  Read More

Alkaptonuria is a rare genetic metabolic disorder characterized by the accumulation of homogentisic acid in the body. Affected individuals lack enough functional levels of an enzyme required to breakdown homogentisic acid. Affected individuals may have dark urine or urine that turns black when exposed to air. However, this change may not occur for several hours after urination and often goes unnoticed. Aside from dark urine that is present fro  Read More

Opsoclonus-myoclonus syndrome (OMS) is a paraneoplastic neurological disorder. It is characterized by associated ocular, motor, behavioral, sleep, and language disturbances. The onset is usually abrupt, often severe, and can become chronic.  Read More

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is characterized by periodic attacks of red (erythematous) plaques that are distributed equally on both sides of the body. A layer of skin can be peeled from these plaques. Symptoms usually improve with age. T  Read More

Idiopathic nodular panniculitis usually begins gradually. Abnormal bumps or masses (nodules) appear in the fatty layer under the skin (subcutaneous fat) of the legs, thighs and buttocks. In some patients, the arms, abdomen, and/or face may be involved. These nodules are usually 1-2 centimeters wide and may be either painful and tender or painless. In some patients, the affected area may become blue and red (erythema), ulcerated (open sore with  Read More

Pantothenate kinase-associated neurodegeneration (PKAN), formerly called Hallervorden-Spatz syndrome, is a rare, inherited neurological movement disorder characterized by the progressive degeneration of the nervous system (neurodegenerative disorder). PKAN is the most common type of neurodegeneration with brain iron accumulation (NBIA), a group of clinical disorders marked by progressive abnormal involuntary movements, alterations in muscle to  Read More

Papillitis, also known as optic neuritis, is characterized by inflammation and deterioration of the portion of the optic nerve known as the optic disk. Also referred to as the "blind spot," the optic disk (optic papilla) is that portion of the optic nerve that enters the eye and joins with the nerve-rich membrane lining the eye (retina). The optic nerves are the pair of nerves (second cranial nerves) that transmit impulses from the retina to t  Read More

Papillon-Lefevre Syndrome (PLS) is an extremely rare genetic disorder that typically becomes apparent from approximately one to five years of age. PLS is characterized by the development of dry scaly patches on the skin of the palms and the soles (palmar-plantar hyperkeratosis) in association with severe inflammation and degeneration of the structures surrounding and supporting the teeth (periodontium). The primary (deciduous) teeth frequently  Read More

Phosphoglycerate kinase deficiency is an inherited metabolic disorder of the enzyme pyruvate kinase, which affects the survival of red blood cells, causing anemia.Cause:Pyruvate kinase deficiency is due to a mutation in the PKLR gene. There are four pyruvate kinase isoenzymes, two of which are encoded by the PKLR.Mutations in the PKLR gene, therefore, cause a deficiency in the pyruvate kinase e  Read More

Cholinergic urticaria is a relatively common disorder of the immune system characterized by an immediate skin reaction (hypersensitivity) to heat, emotional stress, and/or exercise. Symptoms of the disorder include the appearance of distinctive small skin eruptions (hives) with well-defined borders and pale centers, surrounded by patches of red skin (wheal-and-flare reaction). These red areas are typically intensely itchy (pruritus). Occasiona  Read More

Phytantic acid storage disease is a rare genetic disorder. It is also known as Adult Refsum Disease (ARD) and results in numbness or weakening in the hands and feet (peripheral neuropathy).Risk factors-This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations.The parents of an individual with an autosomal recessive condition e  Read More

Propionic acidemia (PA) is an inherited disorder that unbales a person to digest certain types of protein and fats. Moreover, this condition leads to an abnormal buildup of particular acids known as organic acid since it is regarded as an organic acid disorder. Here are some risk factors associated with Propionic acidemia:Inheritance: PA has been inherited in such a pattern that both copies of gene PCCA and PCCB in  Read More

Wiedemann-Rautenstrauch syndrome (WRS), also known as neonatal progeroid syndrome, is a very rare genetic disorder characterized by an aged appearance at birth (old man look) growth delays before and after birth (prenatal and postnatal growth retardation), and deficiency or absence of the layer of fat under the skin (subcutaneous lipoatrophy). It is anticipated that most individuals with WRS have decreased life expectancy. There are few indivi  Read More

Boys with X-linked ichthyosis appear normal at birth. The skin symptoms generally appear within the first year of life. Brownish scales that adhere to the skin are among the first signs of the disorder. The back and legs are most frequently involved early. The face, scalp, palms and soles, and hollows of the elbows and knees are usually spared. In about half of adult males, comma-shaped corneal opacities occur in the eyes (seen on exam  Read More

Camurati-Engelmann disease is a rare genetic disorder characterized by progressive widening and malformation of the shafts of the long bones (diaphyseal dysplasia). Major symptoms may include bone pain, particularly in the legs; skeletal abnormalities; and/or weakness and underdevelopment (hypoplasia) of various muscles. Pain and weakness of the leg muscles may result in an unusual "waddling" walk (gait). Camurati-Engelmann disease is inherite  Read More

Roberts syndrome is a rare genetic disorder characterized by growth delays before and after birth (pre- and postnatal growth deficiency); malformations of the arms and legs (limbs); distinctive abnormalities of the skull and facial (craniofacial) region. Mental retardation occurs in some cases; normal intelligence has also been reported. In infants with Roberts syndrome, the arms and legs may be incompletely developed (limb reducti  Read More

Robinow syndrome is an extremely rare inherited disorder characterized by mild to moderate short stature due to growth delays after birth (postnatal growth retardation); distinctive abnormalities of the head and facial (craniofacial) area; additional skeletal malformations; and/or genital abnormalities. The facial features of infants with Robinow syndrome resemble those of an eight-week-old fetus; within the medical literature, this condition  Read More

Rosenberg-Chutorian syndrome is an extremely rare genetic disorder characterized by the triad of hearing loss, degeneration of the optic nerve (optic atrophy) and neurological abnormalities, specifically disease of the nerves outside of the central nervous system (peripheral neuropathy). The arms and legs are most often affected by peripheral neuropathy. Rosenberg-Chutorian syndrome is inherited as an X-linked disorder with occasional mild sym  Read More

Rosewater syndrome is a mental illness that makes people see and hear things that aren't there. It's caused by brain damage, which can be caused by a disease or injury to the brain. The symptoms of rosewater syndrome are hallucinations and delusions. Hallucinations are things you see or hear that aren't really there, like seeing monsters in your room at night or hearing voices when no one else is around. Delusions  Read More

The diencephalic syndrome is a very rare neurological disorder characterized by failure to thrive, abnormal thinness (emaciation), amnesia, intense sleepiness, unusual eye position and sometimes blindness. It is normally seen in infancy or early childhood but some cases have been reported in older children and even adults. Diencephalic syndrome is usually caused by a brain tumor such as a low-grade glioma or astrocytoma.  Read More

Santavuori disease, a rare genetic disorder, belongs to a group of progressive degenerative neurometabolic diseases known as the neuronal ceroid lipofuscinoses (NCL). These disorders share certain similar symptoms and are distinguished in part by the age at which such symptoms appear. Santavuori disease is considered the infantile form of the neuronal ceroid lipofuscinoses. The NCLs are characterized by abnormal accumulation of certain fatty,  Read More

Santavuori disease, a rare genetic disorder, belongs to a group of progressive degenerative neurometabolic diseases known as the neuronal ceroid lipofuscinoses (NCL). These disorders share certain similar symptoms and are distinguished in part by the age at which such symptoms appear. Santavuori disease is considered the infantile form of the neuronal ceroid lipofuscinoses. The NCLs are characterized by abnormal accumulation of certain fatty,  Read More

POEMS syndrome is an extremely rare multisystem disorder. POEMS is an acronym that stands for (P)olyneuropathy, disease affecting many nerves; (O)rganomegaly, abnormal enlargement of an organ; (E)ndocrinopathy, disease affecting certain hormone-producing glands that help to regulate sexual function, and certain metabolic functions; (M)onoclonal gammopathy or M proteins; and (S)kin abnormalities. Common symptoms include progressive weakness of  Read More

Smith-Lemli-Opitz syndrome (SLOS) is a variable genetic disorder that is characterized by slow growth before and after birth, small head (microcephaly), mild to moderate mental retardation and multiple birth defects including particular facial features, cleft palate, heart defects, fused second and third toes, extra fingers and toes and underdeveloped external genitals in males. The severity of SLOS varies greatly in affected individuals, even  Read More

Smith-Lemli-Opitz syndrome (SLOS) is a variable genetic disorder that is characterized by slow growth before and after birth, small head (microcephaly), mild to moderate mental retardation and multiple birth defects including particular facial features, cleft palate, heart defects, fused second and third toes, extra fingers and toes and underdeveloped external genitals in males. The severity of SLOS varies greatly in affected individuals, even  Read More

Stiff-person syndrome (SPS) is a rare acquired neurological disorder characterized by progressive muscle stiffness (rigidity) and repeated episodes of painful muscle spasms. Muscular rigidity often fluctuates (i.e., grows worse and then improves) and usually occurs along with the muscle spasms. Spasms may occur randomly or be triggered by a variety of different events including a sudden noise or light physical contact. In most cases, other neu  Read More

Sneddon syndrome is a rare progressive disorder affecting the blood vessels characterized by the association of a skin condition and neurological abnormalities. Characteristics include multiple episodes of reduced blood flow to the brain (cerebral ischemia) and bluish net-like patterns of discoloration on the skin surrounding normal- appearing skin (livedo reticularis). Major symptoms may include headache, dizziness, abnormally high blood pres  Read More

Brown-Séquard syndrome is a rare spinal disorder that results from an injury to one side of the spinal cord in which the spinal cord is damaged but is not severed completely. It is usually caused by an injury to the spine in the region of the neck or back. In many cases, affected individuals have received some type of puncture wound in the neck or in the back that damages the spine and causes symptoms to appear. Characteri  Read More

Thrombocytopenia-absent radius (TAR) syndrome is a rare disorder that is present at birth (congenital). It is characterized by low levels of platelets in the blood (thrombocytopenia) and absence (aplasia) of the long, thin bones of the forearms (radii). Other abnormalities are often present including additional skeletal defects such as absence or underdevelopment of the other bone of the forearm (ulna), structural malformations of the heart (c  Read More

Ataxia with vitamin E deficiency (AVED) is a rare inherited neurodegenerative disorder characterized by impaired ability to coordinate voluntary movements (ataxia) and disease of the peripheral nervous system (peripheral neuropathy). AVED is a progressive disorder that can affect many different systems of the body (multisystem disorder). Specific symptoms vary from case to case. In addition to neurological symptoms, affected individuals may ex  Read More

Tolosa-Hunt syndrome is a rare disorder characterized by severe periorbital headaches, along with decreased and painful eye movements (ophthalmoplegia). Symptoms usually affect only one eye (unilateral). In most cases, affected individuals experience intense sharp pain and decreased eye movements. Symptoms often will subside without intervention (spontaneous remission) and may recur without a distinct pattern (randomly). Affected individuals m  Read More

Williams syndrome, also known as Williams-Beuren syndrome, is a rare genetic disorder characterized by growth delays before and after birth (prenatal and postnatal growth retardation), short stature, a varying degree of mental deficiency, and distinctive facial features that typically become more pronounced with age. Such characteristic facial features may include a round face, full cheeks, thick lips, a large mouth that is usually held open,  Read More

Wolf-Hirschhorn syndrome is an extremely rare chromosomal disorder caused by a partial deletion (monosomy) of the short arm ("p") of chromosome 4. Major symptoms may include extremely wide-set eyes (ocular hypertelorism) with a broad or beaked nose, a small head (microcephaly), low-set malformed ears, mental and growth deficiency, heart (cardiac) defects, and seizures. Because the amount of genetic material deleted varies, the symptoms of this  Read More

Wyburn-Mason syndrome is an extremely rare nonhereditary disorder that is present at birth (congenital). Affected infants have arteriovenous malformations (AVMs), which are developmental abnormalities affecting the blood vessels, specifically the arteries, veins and capillaries. Arteries typically carry oxygen-rich blood from the heart to body cells, while veins transport oxygen-deficient blood to the heart and lungs for the exchange of oxygen  Read More