Atypical physeal and subchondral skeletal manifestations in a child with CIPA: a novel NTRK1 mutation case report.

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive disorder caused by mutations in the neurotrophic tyrosine receptor kinase 1 (NTRK1) gene, characterized by impaired pain perception, autonomic dysfunction, and progressive musculoskeletal damage. A 6-year-old girl with ocular and cutaneous albinism, psychomotor retardation, and bilateral hip dislocation was diagnosed with CIPA due to the presence of atraumatic lower limb fractures. Genetic testing revealed a novel NTRK1 splice site mutation (c.851-2A>G). The patient experienced bilateral medial longitudinal arch injuries, multiple Salter-Harris fracture patterns, and imaging characteristics suggestive of neuropathic arthropathy and an unusual periosteal reaction during the course of an 8-year follow-up. Recurrent septic arthritis also resulted in severe deformity of the elbow joint. Unusual periosteal reaction, complex physeal injuries, and synchronous bilateral medial longitudinal arch fractures are among the novel radiologic findings highlighted in this case of CIPA. In this potentially fatal condition, early identification of such patterns is essential for diagnosis, interdisciplinary care, and prevention of irreversible joint damage.