Congenital insensitivity to pain and anhidrosis and central nervous system involvement: expanding the phenotypic spectrum of a novel NTRK1 mutation

An infant, born preterm (1900 g) to non-consanguineous parents, presented with failure to thrive and global developmental delay. Perinatal history was uneventful. Developmental milestones included neck holding at 7 months, sitting with support at 10 months and currently sitting independently. She has a bidextrous reach and speaks monosyllables. She had recurrent febrile episodes requiring hospitalisation, often treated as sepsis despite negative sepsis markers. A history of generalised tonic-clonic seizures, now controlled with levetiracetam, was noted. Parents reported recurrent hyperthermia (up to 104°F) with sun exposure, absence of sweating and lack of pain response since early infancy. Motor examination was normal; however, sensory testing revealed absent pain perception.