Analysis of ornithine transcarbamylase gene mutations in three boys affected with late-onset ornithine transcarbamylase deficiency

Objective: To identify the types of OTC gene mutations in three male patients with late onset ornithine transcarbamylase deficiency (OTCD, MIM #311250).

Methods: Genomic DNA was extracted from peripheral blood leukocytes. The 10 exons and their flanking sequences of the OTC gene were amplified with polymerase chain reaction and subjected to direct DNA sequencing.

Results: Based on DNA sequence analysis, all of the three patients have carried OTC gene mutations. Patients 1 and 2 were both hemizygous for mutation c.586G> A(p.D196N). A novel mutation c.800G> C(p.S267T) were confirmed in patient 3.

Conclusions: p.S267T mutation has affected the conserved amino acid motif of the OTC protein, and is therefore a pathogenic mutation.