3-Hydroxyisobutyryl-CoA Hydrolase (HIBCH) Deficiency Cases Diagnosed by Only HIBCH Gene Analysis and Novel Pathogenic Mutation.

Objective: 3-Hydroxyisobutyryl-CoA hydrolase (HIBCH) deficiency is a rare metabolic disease of valine metabolism. Only 22 cases of HIBCH deficiency have been reported in the literature. Our algorithm could help in the diagnosis of this disease.

Methods: HIBCH gene analysis was performed in all cases.

Results: The common features of our five patients from the same family with a developmental delay, seizures, and neurological regression were the elevation of 3-hydroxy-isobutyryl-carnitine and Leigh-like abnormalities. Unlike other patients in the literature, our patients were diagnosed with HIBCH gene analysis, rather than whole exome sequencing (WES). In all our cases, a missense c.452C>T, p. Ser151Leu homozygous novel pathogenic mutation was detected in the HIBCH gene.

Conclusions: In cases where HIBCH deficiency is considered in our differential diagnosis algorithm, HIBCH gene analysis, which is cost-effective, should be performed instead of WES, and the number of cases should be increased in the literature.