[Analysis of a Chinese pedigree affected with X-linked cardiac valve dysplasia (CVDPX) and congenital chronic pseudo intestinal obstruction (CIIPX) due to a c.443A>G variant of FLNA gene].

Abstract

Objective: To explore the genetic etiology for a Chinese pedigree affected with X-linked cardiac valve dysplasia (CVDPX) and congenital chronic pseudo intestinal obstruction (CIIPX).

Methods: A pedigree presented at the First Hospital of Lanzhou University for CVDPX combined with CIIX was selected as the study subject. Whole exome sequencing (Trio-WES) was carried out, and the candidate variant was verified by Sanger sequencing. This study has been approved by the Medical Ethics Committee of the First Hospital of Lanzhou University (Ethics No. LDYYSZLLKH2024-15).

Results: Both the proband and his affected younger brother were found to harbor a hemizygous c.443A>G (p.Tyr148Cys) variant of the FLNA gene, for which their mother was heterozygous and their father was not a carrier, suggesting an X-linked recessive inheritance pattern. The variant was not recorded in the OMIM and ClinVar databases, and was determined to be likely pathogenic (PM2+PS4+PP2+PP3) based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). The patients had presented with typical CVDPX/CIIPX phenotype, including multiple valve dysplasia and chronic pseudo intestinal obstruction, in addition with gallbladder wall edema and thickening. Bioinformatic analysis showed that the variant site is highly conserved, and multiple algorithms had predicted its pathogenicity.

Conclusion: This study confirmed the diagnosis of CVDPX/CIIX in a Chinese pedigree, expanded the phenotype spectrum of FLNA gene variants, and provided a basis for genetic counseling and prenatal diagnosis for the pedigree.