Targeted exome sequencing identified a novel frameshift variant in the PGAM2 gene causing glycogen storage disease type X.

BACKGROUND: Phosphoglycerate mutase (PGAM) deficiency is associated with a rare glycogen storage disease (glycogenosis type X) in humans caused by pathogenic variants in the PGAM2 gene. Several genes causing autosomal forms of glycogen storage disease (GSD) have been identified, involved in various forms of neuromuscular anomalies.

METHODS: Targeted whole exome sequencing (WES) was performed on the DNA of single affected individual (IV-1) followed by Sanger sequencing confirmation of the identified variant in all available members of the family.

RESULTS: In the present study, the affected individual, presenting mild features of glycogen storage disease type X. Targeted exome sequencing revealed a biallelic frameshift variant (c.687dupC; p. Met230Hisfs*6) in the PGAM2 gene located on chromosome 7p13.

CONCLUSION: In short, we reported a novel homozygous frameshift variant as a cause of glycogen storage disease type X from Pakistani population. The work presented here proves significance of targeted WES in accurate diagnosis of known complex genetic disorders.