Clinical exome sequencing (carrier screening) identifies the gene INPPL1 in a sporadic case of opsismodysplasia

Abstract

Introduction and aim. This study presents a case of opsismodysplasia in a family, characterized by skeletal dysplasia and neu rological complications in two consecutive neonates. Description of the case. Genetic analysis revealed that the father carries a likely benign/variant of uncertain significance (VUS) in exon 14 of the INPPL1 gene (c.1706C>T, p.Thr569Met), while the mother carries a pathogenic variant in exon 15 (c.1809del, p.Trp604GlyfsTer17). These variants follow an autosomal recessive inheritance, confirming carrier status. Additionally, the fa ther is a carrier of a likely pathogenic variant in the CYP17A1 gene (OMIM*609300), specifically in exon 6 (c.1040G>A, p.Ar g347His, heterozygous), affecting 17,20-lyase activity and associated with isolated 17,20-lyase deficiency. Targeted sequencing and Sanger validation elucidated the genetic basis of the condition, emphasizing the importance of genetic testing and coun selling in families with a history of genetic disorders. The detected variants in the INPPL1 gene disrupt SHIP2 protein function, contributing to the observed abnormalities. Conclusion. This study underscores the significance of early genetic diagnosis for reproductive counselling and timely inter vention. Further research into opsismodysplasia’s genetic mechanisms may lead to improved management and therapies for affected individuals. Overall, this case highlights the critical role of genetic analysis in diagnosing and managing rare genetic disorders, offering insights into personalized care and family planning.