[Genetic analysis of a child with Congenital insensitivity to pain due to compound heterozygous variants of SCN9A gene].

OBJECTIVE

To explore the genetic etiology of a child featuring multiple fractures and congenital insensitivity to pain (CIP).

METHODS

A child who had presented at the West China Hospital of Sichuan University on March 16, 2023 for recurrent fractures and CIP was selected as the study subject. Peripheral blood samples of the child and his parents was collected. Trio-whole exome sequencing was carried out. Candidate variants were verified by Sanger sequencing and bioinformatic analysis. This study has been approved by the Medical Ethics Committee of West China Hospital of Sichuan University (No. 2019-772).

RESULTS

Trio-whole exome sequencing revealed that the child has harbored compound heterozygous variants of the SCN9A gene, namely c.560delC (p.P187Rfs*15) and c.829C>T (p.R277*), which were respectively inherited from his father and mother. Homozygous c.829C>T variant had been demonstrated as pathogenic among CIP patients, whilst the c.560delC (p.P187Rfs*15) variant was unreported previously and predicted to be pathogenic based on the guidelines of the American College of Medical Genetics and Genomics (ACMG).

CONCLUSION

The child was diagnosed with CIP due to the compound heterozygous variants of the SCN9A gene. Above finding has enabled genetic counselling and reproductive guidance for this family.