Supplementary Material for: Nail Changes in Congenital Insensitivity to Pain with Anhidrosis: A Case Report

Introduction: Nail changes often reflect underlying systemic disease and may be the presenting manifestation of rare genetic disorders. Case report: We report two brothers who presented with prominent nail abnormalities including dystrophy, brachyonychia, anonychia, paronychia, and pseudo-clubbing, along with acro-osteolysis of distal phalanges. Subsequent evaluation revealed insensitivity to pain and temperature, intellectual disability, recurrent fractures, self-mutilation, and anhidrosis, leading to a diagnosis of congenital insensitivity to pain with anhidrosis (CIPA). Genetic analysis confirmed a novel homozygous NTRK1 gene deletion. Conclusion: This report highlights the importance of nail manifestations as potential diagnostic indicators of CIPA.