Thelansis

  Mucopolysaccharidosis type III (MPS III), part of the mucopolysaccharidoses group, is a lysosomal storage disease characterized by severe and rapid intellectual deterioration. Initial symptoms typically manifest between the ages of 2 and 6 years, presenting with behavioral disorders such as hyperkinesia and aggressiveness, along with intellectual decline, sleep disturbances, and mild dysmorphism. Neurological involvement becomes more pronounced around age 10, leading to losing motor milestones and communication difficulties. Seizures often occur after age 10; some attenuated forms have been reported. Each MPS III subtype (MPS IIIA, MPS IIIB, MPS IIIC, and MPS IIID) results from deficiencies in one of the four enzymes necessary for heparan sulfate (HS) degradation. Specific enzymes responsible for each subtype include heparan sulfamidase for MPS IIIA, alpha-N-acetylglucosaminidase for MPS IIIB, alpha-glucosaminide N-acetyltransferase for MPS IIIC, and N-acetylglucosamine-6-sulfa...