Title: Partial duplication and point mutations of the ornithine carbamoyl transferase (OCT) gene in congenital hyperammonaemia
Abstract: ACT deficiency is an enzymopathy of the urea cycle inherited as a partially dominant X-linked trait. Affected males often die during the neonatal period with untractable hyperammonaemic coma but may sometimes present with a late onset disease. Heterozygous females are sometimes symptomatic. Twenty-two unrelated patients (18 males and 4 females) were studied by single strand conformational polymorphism (SSCP) analysis followed by direct sequencing of the OCT exons. Nine of them were found to carry point mutations already reported by others (G50Z, E87K, L88N, R827, R141Z, P225L) or by our group (R277W, 2 patients). A duplication (4 bp) in exon 5 (nt177-XTCACTCAC Xnt178) was found in a male patient with a severe neonatal OCT deficiency. This change led to a frameshift mutation with no in-frame stop codon. To our knowledge, this is the first duplication reported in OCT deficiency. Eight novel missense mutations were found in 12 additional patients: R40H (exon 2, 3 patients), C109S (exon 4, 1 patient), T125M (exon 5, 1 patient), R129Q (exon 5, 3 patients), G188R (exon 6, 1 patient), A209V (exon 6, 1 patient), H302L (exon 9, 2 patients). Four of these mutations occurred in CpG doublets and all of them involved conserved regions of themore » gene. No such alterations were found in 70 control genes. Phenotype-genotype correlations will be discussed.« less
Publication Year: 1994
Publication Date: 1994-09-01
Language: en
Type: article
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