Novel mutation of SCN9A gene in a family with Paroxysmal Extreme Pain Disorder (PEPD): Considerations of paediatric interest

Introduction: Paroxysmal Extreme Pain Disorder (PEPD) is a rare autosomal dominant disease, caused by mutations in the SCN9A gene, which encodes the NaV1.7 voltage-gated sodium channel alpha subunit. Symptoms generally begin in early infancy with episodes of excruciating, burning and spreading pain in the lower part of the body, typically in the anorectal area, which can last from seconds to hours. Case description: We describe the case of a 5-year-old male with PEPD and a novel heterozygous mutation c.5825c>T (p. Thr1942ile) in the SCN9A gene. This is a novel mutation that has not previously been reported. Discussion: According to the available information, the clinical significance of the variant c.5825c>T (p. Thr1942ile) is unknown. However, its presence in the patient and in others affected family members, reinforces its possible pathogenicity and is suggestive of mutation segregation with the disease in this family. Conclusion: We consider that it is a family case of interest to the pediatrician, for allowing: 1) To be able to intuit it by the clinic early and 2) To be able to confirm it by means of the corresponding genetic study.