Identification of novel mutations in the human ornithine transcarbamylase (OTC) gene of Korean patients with OTC deficiency and transient expression of the mutant proteins in vitro.

The urea cycle plays key roles to prevent the accumulation of toxic nitrogenous compound and synthesize arginine de novo. Ornithine transcarbamylase (OTC) deficiency is the most common inborn error of urea cycle, which is inherited in an X-linked manner. This study was undertaken to characterize molecular defects in Korean patients with OTC deficiency. With direct sequence analysis of OTC gene of 26 unrelated Korean patients with OTC deficiency, 23 different mutations were identified. Among these mutations, eleven were novel mutations. The novel mutations were p.Leu9X, p.Arg26Pro, p.Gly100Arg, p.Met205Thr, p.Lys221Asn, p.Asp249Gly, p.Phe281Ser, p.Val323Met, c.571delC, c.853delC, and c.796-805del. All the novel mutations in this study were tested in 100 normal alleles. In vitro expression study of some of novel missense mutations elucidated the correlation of genotype and phenotype of the OTC deficiency.