Molecular characterization and structure analysis of HPRT in a Chinese patient with Lesch-Nyhan disease.

Lesch-Nyhan disease (LND) is caused by deficiency of hypoxanthine guanine phosphoribosyltransferase (HPRT). The aim of the present study is to characterize the molecular deficiency of a clinical diagnosed Chinese patient with attenuated variant of LND. The coding region and the intron-exon boundaries of HPRT1 gene were sequenced by standard methods, and HPRT activity was assayed by HPLC method. Structure analysis was performed to estimate the consequence of the mutant of HPRT1 gene. A new mutation c.245T>G (p.Ile82Ser) was identified in this patient, and heterozygous mutation was found in the patient's mother. The activity of HPRT in the patient was completely undetectable. Structure study indicates that the mutation of p.Ile82Ser may lead to loss of hydrophobic side chain and disrupt its normal conformation of HPRT protein. It is helpful for diagnosis of LND that sequencing analysis of HPRT1 gene is performed in male infant and juvenile with hyperuricaemia and neurologic dysfunction in Chinese.