Мucopolysaccharidosis I (MPS I) is caused by the deficiency of lysosomal enzyme α-L-Iduronidase. It appears as a result of mutations in the IDUA gene. The most common mutations in the IDUA gene causing MPS I are Q70X and W402X.
The diagnosis MPS I has been confirmed in 16 patients. The dependence of residual α-L-Iduronidase activity in blood leukocytes on the severity of the MPS I disease has been stated. The Q70X і W402X mutations have been found only in patients with severe Hurler type of MPS I. In patients with mild Scheie and Hurler/Scheie types of MPS I the Q70X і W402X mutations have not been found. The comparative assessment of the major mutations frequency has been conducted with the population of Ukraine and other countries.