Prenatal monitoring of ornithine transcarbamoylase deficiency in two families by DNA analysis.

We examined the DNA in two families with ornithine transcarbamoylase (OTC) deficiency. Two point mutations of the OTC gene, a C-to-T (codon 141) and a G-to-A (codon 141), were identified. This allowed prenatal monitoring to be made for two fetuses in each family, using polymerase chain reaction (PCR), followed by allele-specific oligonucleotide hybridization or TaqI digestion of amplified sequence. The diagnoses showed heterozygotes of a wild type gene and the corresponding mutant gene in these fetuses; each was confirmed postnatally.