[P1-163] Clinical and genetic features of nine Chinese patients with classical homocystinuria
[Background] Classical homocystinuria (MIM# 236200 ) is a rare inherited disorder in Mainland China. This study aimed to identify mutations in the cystathionine β-synthase gene (CBS) that are associated with classical homocystinuria of nine Chinese patients. [Methods] Nine Chinese patients were diagnosed at the age of 5 years 4 months to 18 years by plasma total homocysteine and blood amino acids determination. CBS gene analysis was performed for the patients and their families. [Results] All nine patients had significantly increased plasma total homocysteine (142-500 μmol/L vs. the normal range of 0-15 μmol/L) and blood methionine (144.3-500 μmol/L vs. the normal range of 0-50 μmol/L). None of the patients was pyridoxine responsive. Eleven mutations on CBS gene were identified in the nine patients. Eight mutations (IVS3+1G>A, p.Thr493fsX46, p.Thr236Asn, p.Leu230Gln, p.Lys72Ile, p.Ser201ProfsX36, p.Met337IlefsX115, and IVS14-1G>C) were novel. Three mutations (p.Arg125Gln, p.Thr257Met and p.Gly116Arg) had been previously reported. [Conclusion] In this study, eight novel mutations in CBS were identified in nine Chinese patients with classical homocystinuria. None of the hot spot mutations reported in other regions previously was found. These data indicated that Chinese maybe had different CBS mutation spectrum from other population.