Mucopolysaccharidosis type I: characterization of a common mutation that causes Hurler syndrome in Moroccan subjects

A group of 13 Moroccan patients with MPS I and their families, including th ree siblings and twin siblings, was screened for mutations of the alpha-L-i duronidase gene using fluorescence-assisted mismatch analysis (FAMA) and cy cle sequencing of PCR products. The P533R mutation, which is rare in Europe ans, was identified in 92 % of mutant alleles (24/26). This is the highest frequency of this mutation detected in patients with Hurler syndrome. None of the patients carried the W402X or Q70X alleles, the most common MPS I mu tations in Europeans. These results suggest that the P533R mutation constit utes the genetic lesion which results in MPS I in people of Moroccan descen t and provides yet more evidence for the uneven geographical distribution o f mutations in MPS I.