[The detection of the frequent mutations of iduronate-2-sulphatase gene in mucopolysaccharidosis type II patients in Chinese].

OBJECTIVE

To investigate and establish the gene diagnosis methods for the frequent mutations of iduronate-2-sulphatase(IDS) gene in mucopolysaccharidosis type II patients.

METHODS

polymerase chain- reaction-single strand conformation polymorphism PCR-SSCP) analysis was applied to detect the mutations of exons 3, 8 and 9 which were hot spots in the iduronate-2-sulfatase gene; DNA sequencing was applied to analyze the mutations which had been detected by PCR-SSCP; PCR-restriction fragment length polymorphism (PCR-RFLP) was applied to detect the results of DNA sequencing.

RESULTS

Obvious and abnormal bands in exon 9 of the IDS gene were found by applying PCR-SSCP; the mutation(C1672T) of exon 9 was found in the patient through DNA sequencing, which led to amino acid replacement(R468W); the PCR-restriction enzyme digestion showed that only one band(554 bp) appeared in the patient, but there were two bands (257 bp and 297 bp) in his parents, and it verified the results of sequencing analysis.

CONCLUSION

PCR-SSCP analysis, DNA sequencing analysis and PCR-restriction enzyme digestion are effective methods for MPS II diagnosis. Combined applications of these methods can verify and complement each other and improve the accuracy of diagnosis.