Description

Mucopolysaccharidosis type III (MPS III) is a lysosomal storage disease belonging to the group of mucopolysaccharidoses and characterised by severe and rapid intellectual deterioration. The first symptoms appear between the ages of 2 and 6 years, with behavioural disorders (hyperkinesia, aggressiveness) and intellectual deterioration, sleep disorders and very mild dysmorphism. The neurological involvement becomes more prominent around the age of 10 years with loss of motor milestones and communication problems. Seizures often occur after the age of 10. A few cases of attenuated forms have also been reported. Deficiencies in one of the four enzymes required for HS degradation are responsible for each of the MPS III subtypes: heparan sulfamidase for MPS IIIA, alpha-N-acetylglucosaminidase for MPS IIIB, alpha-glucosaminide N-acetyltransferase for MPS IIIC, and N-acetylglucosamine-6-sulfate sulfatase for MPS IIID. The four genes coding for these enzymes have been located (MPS IIIA on 17q25, MPS IIIB on 17q21, MPS IIIC in the pericentromeric region of chromosome 8, MPS IIID on 12q14), and numerous mutations have been identified.

External Information

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