A common mutation, R208X, identified in Vietnamese patients with mitochondrial acetoacetyl-CoA thiolase (T2) deficiency

Abstract

Mitochondrial acetoacetyl-CoA thiolase (T2) deficiency is an inborn error of metabolism affecting isoleucine catabolism and ketone body utilization. This disorder is clinically characterized by intermittent ketoacidotic episodes with no clinical symptoms between episodes. In general, T2 gene mutations are heterogeneous. No common mutations have been identified and more than 70 mutations have been identified in 70 patients with T2 deficiency (including unpublished data). We herein identified a common mutation, R208X, in Vietnamese patients. We identified R208X homozygously in six patients and heterozygously in two patients among eight Vietnamese patients. This R208X mutation was also identified heterozygously in two Dutch patients, however, R208X mutant alleles in the Vietnamese have a different haplotype from that in the Dutch, when analyzed using Msp I and Taq I polymorphisms in the T2 gene. The R208X mutant allele was not so frequent in the Vietnamese since we could not find that mutant allele in 400 healthy Vietnamese controls using the Nla III restriction enzyme assay. DNA diagnosis of T2 deficiency may be applicable to the Vietnamese population.