Congenital enterocyte heparan sulfate deficiency (CEHSD) is a rare genetic disorder that affects the body's ability to absorb nutrients from food. It is caused by a mutation in the gene that codes for the enzyme heparan sulfate 2-O-sulfotransferase (HS2ST). This enzyme is responsible for the production of heparan sulfate, a type of sugar molecule that helps the body absorb nutrients from food. People with CEHSD have a deficiency of this enzyme, which leads to malabsorption of nutrients and other digestive problems. Symptoms of CEHSD include failure to thrive, diarrhea, vomiting, and poor weight gain. Treatment typically involves dietary modifications and supplementation with vitamins and minerals.