Mucopolysaccharidosis Type IIIC (HGSNAT)

Mucopolysaccharidosis type IIIC, also known as Sanfilippo syndrome type C, is a pan-ethnic, autosomal recessive disease caused by pathogenic variants in the gene HGSNAT. This disease is characterized by severe behavioral disturbances, including hyperactivity, sleep disturbances and destructive behavior. The age of onset is usually around 3 to 4 years of age. Other features include intellectual disability, enlarged liver and spleen, stiffness of the joints, hearing loss and seizures. No treatment is known. Life expectancy is approximately 34 years of age, but may be variable. No clear genotype-phenotype correlation is known.









Disease Name
 GeneGuaranteed Exons 
 Inheritance Ethnicity
 Carrier Frequency
 Detection Rate
Residual Risk

Mucopolysaccharidosis, Type IIICHGSNAT2, 4, 17 [18] (*16)ARCaucasian1 in 25977%0.000890471950133571
Mucopolysaccharidosis, Type IIICHGSNAT2, 4, 17 [18] (*16)ARAsian< 1 in 50075%0.000500751126690035
Mucopolysaccharidosis, Type IIICHGSNAT2, 4, 17 [18] (*16)ARWorldwide1 in 48255%0.000934579439252336