Propionic Academia: Exome Sequencing Identified Novel Mutation in Exon 12 of PCCA Gene

Abstract

Propionic acidemia (PA) is a rare autosomal recessive genetic disorder resulting from propionyl-coenzyme A carboxylase deficiency. This mitochondrial enzyme is a heterocopolymer of two subunits a and b that are encoded by PCCA and PCCB genes, respectively. The phenotypes of PCCA mutations are most varied ranging from mild to lethal within a few days after birth because there is great heterogeneity in the mutations of PCCA, while PCCB bears only a limited number of mutations. Deep resequencing of all human genes could potentially identify allelic variants involved in a given rare monogenic disease. Whole exome sequencing (WES) is well justified as an efficient strategy to search for mutations in rare Mendelian disorders. Here, we analyzed an Iranian couple with the history of having a child who died probably due to PA by WES. We could report a novel heterozygous non-sense mutation (p.Y380X) in exon 12 of the PCCA gene, resulting in the protein truncation. We could find that both of parents are carrier for a heterozygous novel non-sense mutation in PCCA gene. We showed that WES in parents, along with appropriate filtering against public SNP databases, is sufficient to identify carriers for a known monogenic disorder, PA, in a consanguineous family.




J Med Cases. 2017;8(4):111-113
doi: https://doi.org/10.14740/jmc2743e