Exome sequencing identifies a novel INPPL1 mutation in opsismodysplasia

Opsismodysplasia is an autosomal recessive skeletal disorder characterized by facial dysmorphism, micromelia, platyspondyly and retarded bone maturation. Recently, mutations in the gene encoding inositol polyphosphate phosphatase-like 1 (INPPL1) are found in several families with opsismodysplasia by a homozygosity mapping, followed by whole genome sequencing. We performed an exome sequencing in two unrelated Japanese families with opsismodysplasia and identified a novel INPPL1 mutation, c.1960_1962delGAG, in one family. The mutation is predicted to result in an in-frame deletion (p.E654del) within the central catalytic 5-phosphate domain. Our results further support that INPPL1 is the disease gene for opsismodysplasia and that opsismodysplasia has genetic heterogeneity.