[Analysis of CNTNAP1 gene variants in a Chinese pedigree affected with lethal congenital contracture syndrome type 7].

OBJECTIVE

To explore the genetic basis for a couple who had developed polyhydramnios during three pregnancies and given birth to two liveborns featuring limb contracture, dyspnea and neonatal death.

METHODS

Whole-exome sequencing (WES) was carried out on fetal tissue and peripheral blood samples from the couple. Suspected variants were verified by Sanger sequencing.

RESULTS

The fetus was found to harbor homozygous nonsense c.3718C>T (p.Arg1240Ter) variants of the CNTNAP1 gene, which were respectively inherited from its mother and father. The variant was unreported previously. According to the guidelines of the American College of Medical Genetics and Genomics, the variant was predicted to be pathogenic (PVS1+PM2+PP4).

CONCLUSION

The novel homozygous nonsense variants of the CNTNAP1 gene probably underlay the lethal congenital contracture syndrome type 7 (LCCS7) in this pedigree. Above finding has enabled genetic counseling and prenatal diagnosis for the family.