Congenital insensitivity to pain with anhidrosis is a rare but devastating hereditary disease. Congenital insensitivity to pain with anhidrosis is caused by a mutation in the neurotrophic receptor tyrosine kinase 1 gene (NRTK1). The condition is characterized by multiple injuries, recurrent infections, and mental retardation. A 7-year-old Kurdish female patient, with a known case of congenital insensitivity to pain with anhidrosis, presented with a left tibial fracture, complicated by incorrect healing, osteomyelitis, and pseudoarthrosis spanning over a number of years. The osteomyelitis and pseudoarthrosis eventually healed after treatment with a combination of a long course of antibiotics, CERAMENT with gentamicin, and 40 sessions of hyperbaric oxygen treatment at 2.4 bar, 113 minutes with two air breaks. This is the first reported case of using hyperbaric oxygen treatment in children with congenital insensitivity to pain with anhidrosis. We discuss potential mechanistic explanations of the association between healing and hyperbaric oxygen treatment. Hyperbaric oxygen treatment may be considered in other cases of complicated infections or treatment-resistant pseudoarthrosis in patients with this rare disease.

Hereditary sensory and autonomic neuropathy type 4 (HSAN4), also known as congenital insensitivity to pain with anhidrosis (CIPA), is a rare genetic disorder caused by NTRK1 gene mutations, affecting nerve growth factor signaling. This study investigates the central nervous system's (CNS) involvement and its relation to pain insensitivity in HSAN4. We present a 15-year-old girl with HSAN4, displaying clinical signs suggestive of CNS impact, including spasticity and a positive Babinski's sign. Using Technetium-99m ethyl cysteinate dimer single-photon emission computed tomography (Tc-99m ECD SPECT) imaging, we discovered perfusion deficits in key brain regions, notably the cerebellum, thalamus, and postcentral gyrus. These regions process pain signals, providing insights into HSAN4's pain insensitivity. This study represents the first visualization of CNS perfusion abnormality in an HSAN4 patient. It highlights the intricate relationship between the peripheral and central nervous systems in HSAN4. The complexity of HSAN4 diagnosis, involving potential unidentified genes, underscores the need for continued research to refine diagnostic approaches and develop comprehensive treatments.

Hereditary sensory and autonomic neuropathy type 4 (HSAN4), or congenital insensitivity to pain with anhidrosis (CIPA), is a rare autosomal recessive disorder caused by mutations in the NTRK1 gene, resulting in pain insensitivity, anhidrosis, and temperature dysregulation. This report focuses on oral manifestations in an 11-year-old girl with CIPA, highlighting the need for early intervention and comprehensive care. The patient had a history of recurrent oral injuries and an unexplained fever, with a confirmed HSAN4 diagnosis through genetic analysis. Clinical features included pain insensitivity, anhidrosis, and intellectual disability. Dental history revealed emergency care, suboptimal oral hygiene, early tooth loss, and infections. Extra-oral examination showed nail-biting and injuries, while intra-oral assessment revealed ulcers and scars. Radiographic evaluation indicated mandibular alveolar bone thinning and periapical lesions in the lower incisors. This case emphasizes the complex challenges of CIPA, including pain insensitivity, recurring fever episodes, and self-inflicted injuries. Early diagnosis and specific dental care are vital to prevent orofacial trauma, necessitating a proactive interdisciplinary approach for comprehensive care.

Hereditary sensory and autonomic neuropathies (HSAN) are rare, genetically inherited disorders characterized by impaired unmyelinated nerve fiber function. Here we report a patient with self-mutilation behavior and decreased response to pain, suggestive of an underlying small fiber neuropathy. Nerve conduction studies were normal but sympathetic skin response was absent at the left arm. Intradermal histamine challenge test was performed to evaluate the function of small unmyelinated nerve fibers and revealed absence of a flare response. Using whole genome sequencing, a novel variant in the neurotrophic tyrosine kinase type 1 gene was identified, expanding the known disease-causing variants associated with HSAN type 4. Through this case, we demonstrate the role of the histamine challenge test in patients suspected to have a small fiber neuropathy where electrophysiological testing may be normal and who may present with non-specific symptoms including hypotonia and failure to thrive. The information gained can guide genetic testing and contribute to interpretation of new variants identified.