Mucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disorder caused by a genetic defect in alpha-L-iduronidase (IDUA) which is involved in the degradation of dermatan and heparan sulfates. The disease has severe and milder phenotypic subtypes. The aim of this study was the detection of mutations in the IDUA gene from 12 additional MPS I patients with various clinical phenotypes (severe, 8 cases; intermediate, 3 cases; mild, 1 case).
Patients and methods: In this study, the IDUA mutations in eight unrelated Tunisian families were performed by amplifying and sequencing the IDUA exons and intron-exon jonctions.
Results: Five IDUA mutations were detected: one is the L578Q, a novel mutation found, in milder patient. The others were the previously described: P533R, Y581X, F602X and R628X that produce a severe and intermediate phenotype. In addition, eighteen variants, including eight previously unreported polymorphisms (IVS6+21c>a, IVS7+79c>t, IVS7-45 g>c, IVS9+36t>c, IVS10+140c>a, IVS11+33c>t, IVS12+13c>t and IVS12-31c>g), were detected.
Conclusion: This paper, showed a heterogeneous pattern of mutations and polymorphisms among Tunisian patients.