Identification and Functional Characterization of Novel and Recurrent NTRK1 Variants in Chinese Families With Congenital Insensitivity to Pain With Anhidrosis: A Combined Clinical, Genetic, and Functional Study.

Background: Congenital insensitivity to pain with anhidrosis (CIPA) is a rare inherited autosomal recessive disorder characterized by insensitivity to noxious stimuli, anhidrosis, recurrent fever, and intellectual disability. CIPA is mainly caused by mutations in the neurotrophic tyrosine kinase receptor type 1 gene (NTRK1). This study aims to identify pathogenic mutations underlying CIPA in two unrelated Chinese families.Methods: DNA was extracted from blood samples of patients and their available family members and subjected to whole exome sequencing (WES). Real-time PCR (qPCR), Gap-PCR, and Sanger sequencing were applied to verify the identified variants.Result: We found novel compound gross deletion mutations [exon1-6 del (g.1-1258_10169del); exon5-7 del (g.6995_11999del)] of NTRK1 (MIM 191315) gene in family 1 and the compound heterozygous mutations [c.851-33T>A; exon5-7 del (g.6995_11999del)] in family 2. Interestingly, we discovered the intragenic novel gross deletion [exon5-7 del (g.6995_11999del)] mediated by recombination between Alu elements.Conclusions: The present study highlights two rare gross deletion mutations in the NTRK1 gene associated with CIPA in two unrelated Chinese families. The deletion of exon1-6 (g.1-1258_10169del) is thought to be the largest NTRK1 deletion reported to date. Our findings expand the mutation spectrum of NTRK1 mutations in the Chinese and could be useful for prenatal interventions and more precise pharmacological treatments to patients. WES conducted in our study is a convenient and useful tool for clinical diagnosis of CIPA and other associated disorders.

The human TRKA gene encodes a high-affinity tyrosine kinase receptor for nerve growth factor. Congenital insensitivity to pain with anhidrosis (CIPA) is an autosomal recessive genetic disorder reported from various countries and characterized by anhidrosis (inability to sweat), the absence of reaction to noxious stimuli, and mental retardation. We have found that TRKA is the gene responsible for CIPA. We have studied TRKA in 46 CIPA chromosomes derived from 23 unrelated Japanese CIPA families. including three that have been previously reported, and identified 11 novel mutations. Four (L93P, G516R, R648 C, and D668Y) are missense mutations that result in amino acid substitutions at positions conserved in the TRK family, including TRKA, TRKB, and TRKC. Three (S131 fs, L579 fs, and D770 fs) are frameshift mutations. Three (E164X, Y359X, and R596X) are nonsense mutations. The other is an intronic branch-site (IVS7-33T-->A) mutation, causing aberrant splicing in vitro. We also report the characterization of eight intragenic polymorphic sites, including a variable dinucleotide repeat and seven single nucleotide polymorphisms, and describe the haplotypic associations of alleles at these sites in 106 normal chromosomes and 46 CIPA chromosomes. More than 50% of CIPA chromosomes share the frameshift mutation (R548 fs) that we described earlier. This mutation apparently shows linkage disequilibrium with a rare haplotype in normal chromosomes, strongly suggesting that it is a common founder mutation. These findings represent the first extensive analysis of CIPA mutations and associated intragenic polymorphisms; they should facilitate the detection of CIPA mutations and aid in the diagnosis and genetic counseling of this painless but severe genetic disorder with devastating complications.

Identification of a novel mutation of the NTRK1 gene in patients with congenital insensitivity to pain with anhidrosis (CIPA)

Congenital Insensitivity to Pain with Anhidrosis (CIPA) is a rare genetic disorder affecting the autonomic nervous system, leading to an inability to feel pain, temperature, or sweat1. This condition is caused by mutations in the NTRK1 gene, which encodes a receptor for nerve growth factor (NGF). The lack of NGF signaling results in the improper development and function of sensory and sympathetic neurons. Patients with CIPA often suffer from repeated injuries, infections, and hyperthermia due to their inability to sense pain and regulate body temperature. Management focuses on preventing injuries, controlling infections, and providing supportive care, as there is no definitive cure for CIPA. We present several hypotheses for treating CIPA using stem cells and modern genetic techniques. One approach involves using induced pluripotent stem cells (iPSCs) to replace defective neurons. Another hypothesis suggests in vivo gene editing of neural progenitors to restore TrkA function. Additionally, mesenchymal stem cells (MSCs) genetically modified to overexpress NGF could provide trophic support. Other strategies include epigenetic modulation of NTRK1 expression and exosome-mediated gene therapy. These innovative approaches aim to address the underlying genetic defects and restore normal cellular functions in CIPA patients.

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive disease characterized by anhidrosis, insensitivity to noxious stimuli, and mental retardation. Mutations in the NTRK1 gene are associated with the pathogenesis of CIPA. In this study, we performed a clinical and genetic analysis on the NTRK1 gene in four Korean patients with CIPA. All patients had typical clinical manifestations of CIPA, including anhidrosis, recurrent fever, absent pain perception, and developmental delay. Sequencing analysis revealed one predominant mutation, c.851-33T>A, in four affected alleles and three novel mutations, including c.287+2dupT, c.2155G>A (p.Glu719Lys), and c.1218delC (p.Pro407ArgfsX), in each affected allele. For one patient, who was heterozygous for c.851-33T>A, another mutation could not be identified, suggesting that a possible hidden intronic or large genomic mutation may have been present. This study extends the spectrum of mutations in the NTRK1 gene and confirms that Korean patients with CIPA have the same genetic background as other ethnicities.

Congenital insensitivity to pain with anhidrosis (CIPA) or hereditary sensory and autonomic neuropathy type IV (HSAN-IV) is an autosomal recessive disorder characterized by recurrent episodic fevers, anhidrosis (inability to sweat), absence of reaction to noxious (or painful) stimuli, self-mutilating behavior and mental retardation. The anomalous pain and temperature sensation and anhidrosis in CIPA are due to the absence of afferent neurons activated by tissue-damaging stimuli and a loss of innervation of eccrine sweat glands, respectively. Nerve growth factor (NGF) supports the survival of nociceptive sensory and autonomic sympathetic neurons as well as cholinergic neurons of the basal forebrain. The human TRKA (NTRKI) gene located on chromosome 1 (1q21-q22) encodes a receptor tyrosine kinase (RTK) which is autophosphorylated in response to NGF, thus, activating various pathways of intracellular signal transduction. We earlier identified the genetic basis of CIPA by detecting mutations in TRKA gene of patients. Defects in NGF signal transduction at its receptor lead to failure to survive as various NGF dependent neurons are not maintained, most probably due to apoptosis during development. TRKA mutations are distributed in an extracellular domain involved in NGF binding, as well as in the intracellular signal-transduction domain. Missense mutations with loss of function provide considerable insight into the structure-function relationship in the RTK family. In view of the fact that defects in TRKA cause CIPA, the molecular pathology of CIPA provides unique opportunities to explore critical roles of the NGF-TRKA receptor system. Thus, CIPA can serve as a useful model to determine mechanisms of development and maintenance of NGF-dependent neurons in autonomic, sensory and central nervous systems, as well as the physiology of these neurons in humans.

Congenital insensitivity to pain with anhidrosis (CIPA) represents a rare genetic disorder characterized by complete absence of pain sensation and inability to sweat, primarily attributed to mutations in the NTRK1 gene. While modern medicine has elucidated the molecular mechanisms underlying this condition, traditional Ayurvedic medicine offers alternative perspectives through its constitutional framework and understanding of sensory dysfunction. Objective: This study explores the correlation between Ayurvedic principles and CIPA manifestations, examining how classical texts describe similar conditions and proposing an integrative approach to understanding this complex disorder. Methods: A systematic review of classical Ayurvedic texts including Charaka Samhita, Sushruta Samhita, and Ashtanga Hridaya was conducted alongside contemporary literature on CIPA. Comparative analysis focused on symptomatology, constitutional predisposition, and therapeutic approaches documented in traditional sources. Results: Ayurvedic literature describes conditions resembling CIPA under various terminologies including "Sparsha Ajna" (loss of tactile sensation) and "Sweda Abhava" (absence of sweating). The disorder correlates with specific Vata-Pitta constitutional imbalances, particularly affecting the nervous system and thermal regulation mechanisms described in classical texts. Conclusion: Integration of Ayurvedic understanding with modern genetic knowledge provides a holistic framework for comprehending CIPA, potentially offering complementary therapeutic strategies focused on constitutional management and symptomatic palliation.

Congenital insensitivity to pain with anhidrosis (CIPA) is an autosomal recessive genetic disorder characterized by insensitivity to pain, anhidrosis (the inability to sweat) and mental retardation. Nerve growth factor (NGF) is a well-known neurotrophic factor essential for the survival and maintenance of NGF-dependent neurons, including primary afferent neurons with thin fibers and sympathetic postganglionic neurons, during development. NGF is also considered to be an inflammatory mediator associated with pain, itch and inflammation in adults. CIPA results from loss-of-function mutations in the NTRK1 gene-encoding TrkA (tropomyosin-related kinase A), a receptor tyrosine kinase for NGF. Defects in NGF-TrkA signal transduction lead to the failure of survival of various NGF-dependent neurons. As a result, patients with CIPA lack NGF-dependent neurons. Recent studies have revealed that mutations in the NGFB gene-encoding NGF protein also cause congenital insensitivity to pain. Using the pathophysiology of CIPA as a foundation, this review investigates the ways in which NGF-dependent neurons contribute to interoception, homeostasis and emotional responses and, together with the brain, immune and endocrine systems, play crucial roles in pain, itch and inflammation. The NGF-TrkA system is essential for the establishment of neural networks for interoception, homeostasis and emotional responses. These networks mediate reciprocal communication between the brain and the body in humans.

Congenital insensitivity to pain with anhidrosis (CIPA) is an autosomal recessive disorder caused by mutations in the neurotrophic tyrosine receptor kinase 1 (NTRK1) gene which encodes the receptor for nerve growth factor (NGF). We report the clinical course in three sibs with CIPA and proven NTRK1 gene mutations with a follow-up over a 25-year period in one of them. They had the characteristic clinical features of an abnormally high pain threshold, and mental retardation; in addition their clinical course was marked by the occurrence of early onset renal disease with recurrent microhematuria and proteinuria and frequent observations of increased serum creatinine and blood urea levels. Light microscopy study of a renal biopsy performed in one of them at age of 20 months showed focal glomerulosclerosis, interstitial fibrosis and tubular atrophy. This patient and his younger brother died because of renal failure at the age of 25 years and 14 years, respectively. The sister still alive showed renal impairment and deep venous thrombosis associated with lupus anticoagulant activity, decrease of circulating autoreactive CD5 (+) B lymphocytes and increased urinary levels of IgG and kappa and lambda light chains, suggesting a possible defect in regulation of B-lymphocyte function. In the light of the NGF-related molecular defect, the extraneurological tissue involvement in CIPA might in part reflect dysregulation of immune mechanisms which possibly brings about a chronic inflammatory response. This, in turn, could result in renal disease which should be mentioned among the life-threatening complications associated with this disorder.

Congenital insensitivity to pain with anhidrosis (CIPA) is an autosomal recessive disorder caused by mutations in the neurotrophic tyrosine receptor kinase 1 (NTRK1) gene, which encodes the receptor for nerve growth factor. We report the clinical course of a 7-year-old girl with CIPA and proven NTRK1 mutation. In addition to recurrent dislocation of the left hip joint and avascular necrosis of the left talus, the patient also presented with recurrent infections secondary to hypogammaglobulinemia, a feature not previously known to be associated with CIPA. The patient was treated with regular administration of intravenous immunoglobulins. Conservative treatment of the recurrent left hip dislocation by cast immobilization and bracing was implemented to stabilize the joint. The implication of the immune system of the reported patient broadens the clinical phenotype associated with NTRK1 mutations.

Congenital insensitivity to pain with anhidrosis (CIPA), also known as Hereditary Sensory and Autonomic Neuropathy type IV (HSAN IV), is a rare autosomal recessive disorder which affects the peripheral nervous system. CIPA is caused by mutations in the NTRK1 gene located on chromosome 1 (1q21-q22) [1]. Mutations cause a loss of function with subsequent failure of Trk-A/s-NGF signaling. In this report, we describe the case of a Turkish patient with CIPA with a novel homozygous mutation in NTRK1 gene. The patient is a 7-year-old male, who was diagnosed clinically with CIPA at the age of 10 months while being investigated for episodes of high fever and anhidrosis. He had history of numerous hospitalizations due to fever of unknown origin, chronic otitis media and febrile convulsion at the age of 6 months. Results of extensive examinations including karyotype, blood and urine amino acids, TANDEM mass spectrometry, urinary organic acids, uric acid, lactate, pyruvate, ammonia, humoral and cellular immunity, ophthalmic examination, electromyography, brain magnetic resonance imaging and gene analysis for familial Mediterranean fever all were normal. He also had surgery for a tibial fracture that occurred after falling while playing at the age of 5 years. He had a prior history of multiple fractures of the tibia and ankles. These were after minor trauma and there were no signs of pain subsequent to these fractures. Examination at the age of 7 years revealed wide-based ataxic gait, severely delayed speech (produced only simple single words), absent corneal reflex, tongue bleeding due to self-inflicted bites, eczematous lesions in skin folds, gen

Heterotopic ossifications and Charcot joints: Congenital insensitivity to pain with anhidrosis (CIPA) and a novel NTRK1 gene mutation

A case of congenital insensitivity to pain with anhidrosis.

Congenital insensitivity to pain with anhidrosis (CIPA) is identified as a genetic disorder of mutations in the human TrkA known as high affinity receptor of nerve growth factor (NGF). NGF signal through TrkA promotes anti-apoptotic activity in hematopoietic cells including B lymphocytes. Here we studied the effect of NGF on anti-apoptotic activity by using human EBV-immortalized B lymphoblastoid cell lines (EB-LCLs) derived from a patient with CIPA and the associated carriers of CIPA. The TrkA(mt/mt) EB-LCL derived from the CIPA patient and the TrkA(wt/mt) EB-LCL derived from the carrier with the heterozygous TrkA mutation did not show any responses to NGF on anti-apoptotic activity. We concluded that this phenomenon is one of the pathogeneses of CIPA.

Congenital Loss of Permanent Teeth in a Patient With Congenital Insensitivity to Pain With Anhidrosis due to 2 Novel Mutations in the NTRK1 Gene