Congenital insensitivity to pain with anhidrosis (CIPA) in Israeli-Bedouins: genetic heterogeneity, novel mutations in the TRKA/NGF receptor gene, clinical findings, and results of nerve conduction studies

Congenital insensitivity to pain with anhidrosis (CIPA), a rare and severe disorder, comprises absence of sensation to noxious stimuli, inability to sweat, and recurrent episodes of hyperthermia. It has a relatively high prevalence in the consanguineous Israeli-Bedouins. Clinical studies of 28 patients are reported here. Using the linkage analysis approach, we linked the disease in 9 of 10 unrelated Israeli-Bedouin families with CIPA to the TrkA gene, which encodes the receptor for nerve growth factor. In one family, linkage was excluded, implying that another gene, yet unidentified, is involved. Two new mutations in the tyrosine kinase domain of the TrkA gene were identified in our CIPA patients: a 1926-ins-T in most of the southern Israeli-Negev CIPA patients, and a Pro- 689-Leu mutation in a different isolate of Bedouins in northern Israel. Eight prenatal diagnoses were made in the southern Israeli-Negev Bedouins, two by linkage analysis and six by checking directly for the 1926-ins-T mutation. Three polymorphisms in the TrkA protein kinase encoding domain were also observed.     

Congenital insensitivity to pain with anhidrosis (CIPA): Novel mutations of the TRKA (NTRK1) gene,a putative uniparental disomy,and a linkage of the mutant TRKA and PKLR genes in a family with CIPA and pyruvate kinase deficiency

Congenital insensitivity to pain with anhidrosis is an autosomal recessive hereditary disorder characterized by recurrent episodic fever, anhidrosis (inability to sweat), absence of reaction to noxious stimuli, self‐mutilating behavior, and mental retardation. The human TRKA gene (NTRK1), located on chromosome 1q21‐q22 encodes the receptor tyrosine kinase for nerve growth factor. We reported that TRKA is the gene responsible for CIPA and we developed a comprehensive strategy to screen for TRKA mutations and polymorphisms, as based on the gene’s structure and organization. Here we report eight novel mutations detected as either a homozygous or heterozygous state in nine CIPA families from five countries. Mendelian inheritance of the mutations was confirmed in seven families for which samples from either parent were available. However, non‐mendelian inheritance seems likely for the family when only samples from the mother and siblings, (but not from the father) were available. A paternal uniparental disomy for chromosome 1 is likely to be the cause of reduction to homozygosity of the TRKA gene mutation in this family. Interestingly, a Hispanic patient from the USA has two autosomal genetic disorders, CIPA and pyruvate kinase deficiency, whose genetic loci are both mapped to a closely linked chromosomal region. A splice mutation and a missense mutation were detected in the TRKA and PKLR genes from the homozygous proband, respectively. Thus, concomitant occurrence of two disorders is ascribed to a combination of two separate mutant genes, not a contiguous gene syndrome. This finding suggests a mechanism responsible for two autosomal genetic disorders in one patient. All these data further support findings that TRKA defects can cause CIPA in various ethnic groups. This will aid in diagnosis and genetic counseling of this painless but severe genetic disorder. Hum Mutat 18:308–318, 2001. © 2001 Wiley‐Liss, Inc.     

Congenital insensitivity to pain with anhidrosis (CIPA) in Israeli‐Bedouins: Genetic heterogeneity,novel mutations in the TRKA/NGF receptor gene,clinical findings,and results of nerve conduction studies

Congenital insensitivity to pain with anhidrosis (CIPA), a rare and severe disorder, comprises absence of sensation to noxious stimuli, inability to sweat, and recurrent episodes of hyperthermia. It has a relatively high prevalence in the consanguineous Israeli‐Bedouins. Clinical studies of 28 patients are reported here. Using the linkage analysis approach, we linked the disease in 9 of 10 unrelated Israeli‐Bedouin families with CIPA to the TrkA gene, which encodes the receptor for nerve growth factor. In one family, linkage was excluded, implying that another gene, yet unidentified, is involved. Two new mutations in the tyrosine kinase domain of the TrkA gene were identified in our CIPA patients: a 1926‐ins‐T in most of the southern Israeli‐Negev CIPA patients, and a Pro‐ 689‐Leu mutation in a different isolate of Bedouins in northern Israel. Eight prenatal diagnoses were made in the southern Israeli‐Negev Bedouins, two by linkage analysis and six by checking directly for the 1926‐ins‐T mutation. Three polymorphisms in the TrkA protein kinase encoding domain were also observed. Am. J. Med. Genet. 92:353–360, 2000. © 2000 Wiley‐Liss, Inc.     

Anti-Apoptotic Effect of Nerve Growth Factor Is Lost in Congenital Insensitivity to Pain with Anhidrosis (CIPA) B Lymphocytes

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 insensitivity to pain with anhidrosis (CIPA): effect of TRKA (NTRK1) missense mutations on autophosphorylation of the receptor tyrosine kinase for nerve growth factor

Human TRKA (NTRK1) encodes the receptor tyrosine kinases (RTKs) for nerve growth factor (NGF) and is the gene responsible for congenital insensitivity to pain with anhidrosis (CIPA), an autosomal recessive disorder characterized by a lack of pain sensation and anhidrosis. We reported 11 putative missense mutations in 31 CIPA families from various ethnic groups. Here we have introduced the corresponding mutations into the TRKA cDNA and examined NGF-stimulated autophosphorylation. We find that wild-type TRKA precursor proteins in a neuronal and a non-neuronal cell line were differentially processed and phosphorylated in an NGF-dependent and -independent manner, respectively. Two mutants (L93P and L213P) in the extracellular domain were aberrantly processed and showed diminished autophosphorylation in neuronal cells. Five mutants (G516R, G571R, R643W, R648C and G708S) in the tyrosine kinase domain were processed as wild-type TRKA but showed significantly diminished autophosphorylation in both neuronal and non-neuronal cells. In contrast, R85S and (H598Y; G607V), detected previously as double and triple mutations, are probably polymorphisms in a particular ethnic background. The other putative mutant D668Y might be a rare polymorphism or might impair the function of TRKA without compromising autophosphorylation. Mutated residues in the tyrosine kinase domain are conserved in various RTKs and probably contribute to critical function of these proteins. Thus, naturally occurring TRKA missense mutations with loss of function provide considerable insight into the structure-function relationship in the RTK family. Our data may aid in developing a drug which targets the clinically devastating 'complex regional pain syndrome'.     

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

Congenital insensitivity to pain with anhidrosis (CIPA), also known as hereditary sensory and autonomic neuropathy type IV (HSAN-IV), is a rare and severe autosomal recessive disorder. We report on an adult female patient whose clinical findings during childhood were not recognized as CIPA. There was neither complete anhidrosis nor a recognizable sensitivity to heat. Tumorlike swellings of many joints and skeletal signs of Charcot neuropathy developed in adolescence which, together with a history of self-mutilation, led to a clinical suspicion of CIPA confirmed by identification of a novel homozygous variant c.1795G > T in the NTRK1 gene in blood lymphocytes. Both parents were heterozygous for the mutation. The variant predicts a premature stop codon (p.Gly599Ter) and thus represents a pathogenic variant; the first reported in the Southeastern European population.     

Ataxia-telangiectasia: founder effect among north African Jews

The ATM gene is responsible for the autosomal recessive disorder ataxia- telangiectasia (A-T), characterized by cerebellar degeneration, immunodeficiency and cancer predisposition. A-T carriers were reported to be moderately cancer-prone. A wide variety of A-T mutations, most of which are unique to single families, were identified in various ethnic groups, precluding carrier screening with mutation-specific assays. However, a single mutation was observed in 32/33 defective ATM alleles in Jewish A-T families of North African origin, coming from various regions of Morocco and Tunisia. This mutation, 103C-->T, results in a stop codon at position 35 of the ATM protein. In keeping with the nature of this mutation, various antibodies directed against the ATM protein failed to defect this protein in patient cells. A rapid carrier detection assay detected this mutation in three out of 488 ATM alleles of Jewish Moroccan or Tunisian origin. This founder effect provides a unique opportunity for population-based screening for A-T carriers in a large Jewish community.      

Congenital insensitivity to pain with anhidrosis: a case report.

Congenital insensitivity to pain with anhidrosis (CIPA) is a very rare genetic disorder of the peripheral nervous system characterized by recurrent episodes of unexplained fever, generalized anhidrosis, insensitivity to pain and temperature, and accompanied by self-mutilating behavior and mental retardation. We report on a 16 month-old boy with CIPA who exhibited these characteristic clinical features. A sural nerve biopsy revealed markedly reduced numbers of unmyelinated and small myelinated fibers, consistent with the characteristic features of CIPA.     

Abnormal neutrophil chemotactic activity in children with congenital insensitivity to pain with anhidrosis (CIPA): the role of nerve growth factor

A 1926-ins-T mutation in the TrkA gene encoding the tyrosine kinase receptor for nerve growth factor (NGF) was previously documented in patients with congenital insensitivity to pain with anhidrosis (CIPA). These patients suffer from skin lacerations which often evolve into deep tissue infections. Abnormality in neutrophil functions may explain this high rate of severe infections. In this study we show that chemotaxis was significantly (P < 0.001) suppressed in patients' neutrophils, compared to healthy controls. Although NGF alone did not exert a chemotactic effect, its presence enhanced both migration toward fMLP and phosphorylation of MAP kinases (ERK and JNK) in neutrophils from healthy controls, but not in neutrophils from CIPA patients. The significantly impaired chemotactic activity of neutrophils from a CIPA patient, which has been attributed to the molecular defect in the TrkA receptor, may contribute to the high rate of infection.     

A single Mediterranean,possibly Jewish,origin for the Val59Gly CDKN2A mutation in four melanoma-prone families

We have screened for CDKN2A germline mutations in 49 Jewish families with two or more cases of melanoma. The Val59Gly mutation, one of the three different alterations identified among these families, was also detected independently in two kindreds from France and one from Spain. The impact of the Val59Gly substitution on the function of the cyclin-dependent kinase inhibitor p16(INK4a), a product of the CDKN2A gene, was assessed by protein-protein interaction and cell proliferation assays and related to potential structural alterations predicted by molecular modeling. Seven microsatellite markers in the vicinity of the CDKN2A gene were used to determine whether the mutation in these families is identical by descent, or represents a mutational hotspot in the CDKN2A gene. Our results show that the Val59Gly substitution impairs p16(INK4a) function, and this dysfunction is consistent with structural predictions. All melanoma-affected individuals tested in the families under study harbor this mutation. Interestingly, the Israeli pedigree includes an affected individual who is homozygous for the Val59Gly mutation. A common haplotype of microsatellite markers has been demonstrated for mutation carriers in all four pedigrees. The Israeli pedigree and one of the French melanoma families are of Moroccan and Tunisian Jewish descent, respectively, and the other families originate from regions of France and Spain close to the Pyrenees. We conclude that the Val59Gly mutation is a major contributor to melanoma risk in the families under study and that it may derive from a single ancestral founder of Mediterranean (possibly Jewish) origin.     

Nerve growth factor and the physiology of pain: lessons from congenital insensitivity to pain with anhidrosis

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.     

Tay-Sachs disease and HEXA mutations among Moroccan Jews

Moroccan Jewry (N>750,000) is the only non-Ashkenazi Jewish community in which Tay-Sachs disease (TSD) is not extremely rare. Previous studies among Moroccan Jewish TSD families identified three HEXA mutations. In this study, extended to enzyme-defined and new obilgate TSD carriers, we found four additional mutations. One of them is a novel, IVS5-2(A→G) substitution, resulting in exon skipping, and it was found only among enzyme-defined carriers. The seven HEXA identified mutations among Moroccan Jews are: ΔF^304/305, R170Q, IVS-2(A→G), Y180X, E482K, 1278+TATC, and IVS12+1(G→C). Their respective distribution among 51 unrelated enzyme-defined and obligate carriers is 22:19:6:1:1:1:1. The mutation(s) remain unknown in only three enzyme-defined carriers. Five of the seven Moroccan mutations, including the three most common ones, were not found among Ashkenazi Jews. Compared with the much larger and relatively homogeneous Ashkenazi population, the finding among Moroccan Jews probably reflects their much longer history. Hum Mutat 10:295–300, 1997. © 1997 Wiley-Liss, Inc.     

Molecular basis of congenital insensitivity to pain with anhidrosis (CIPA): Mutations and polymorphisms in TRKA (NTRK1) gene encoding the receptor tyrosine kinase for nerve growth factor

Congenital insensitivity to pain with anhidrosis (CIPA), also referred to as hereditary sensory and autonomic neuropathy type IV (HSAN‐IV), is an autosomal recessive hereditary disorder characterized by recurrent episodic fever, anhidrosis (inability to sweat), absence of reaction to noxious stimuli, self‐mutilating behavior, and mental retardation. The TRKA (NTRK1) gene located on chromosome 1 (1q21‐q22), consists of 17 exons and spans at least 23 kb. TRKA encodes the receptor tyrosine kinase (RTK) for nerve growth factor (NGF) and is the gene responsible for CIPA. Defects in NGF signal transduction at the TRKA receptor lead to failure to support survival of sympathetic ganglion neurons and nociceptive sensory neurons derived from the neural crest. Thirty‐seven different TRKA mutations, identified in patients in various countries, including nine frameshift, seven nonsense, seven splice, and 14 missense mutations, are distributed in an extracellular domain involved in NGF binding, as well as in the intracellular signal‐transduction domain. Extensive analysis of CIPA mutations and associated intragenic polymorphisms should facilitate detection of CIPA mutations and aid in the diagnosis and genetic counseling of this painless but severe genetic disorder with devastating complications. In addition, naturally occurring TRKA missense mutations with loss of function provide considerable insight into the structure–function relationship in the RTK family. Further, molecular pathology of CIPA would provide unique opportunities to explore critical roles of the autonomic sympathetic nervous system as well as peripheral sensory nervous system that transmit noxious stimuli in humans. Hum Mutat 18:462–471, 2001. © 2001 Wiley‐Liss, Inc.     

Familial hypercholesterolemia in Morocco: first report of mutations in the LDL receptor gene

Familial hypercholesterolemia (FH) is a genetic disorder mainly caused by defects in the low-density lipoprotein receptor (LDLR) gene, although it can also be due to alterations in the gene encoding apolipoprotein B (familial defective apoB or FDB) or in other unidentified genes. In Morocco, the molecular basis of FH is unknown. To obtain information on this issue, 27 patients with FH from eight unrelated families were analyzed by screening the LDLR (PCR-SSCP and Southern blot) and apoB genes (PCR and restriction enzyme digestion analysis). None of the patients carried either the R3500Q or the R3531C mutation in the apoB gene. By contrast, seven mutations in the LDLR gene were identified, including five missense mutations on exons 4, 6, 8, and 14 (C113R, G266C, A370T, P664L, C690S) and two large deletions (FH Morocco-1 and FH Morocco-2). The two major rearrangements and the missense mutation G266C are novel mutations and could well be causative of FH in the Moroccan population. This study has yielded preliminary information on the mutation spectrum of the LDLR gene among patients with FH in Morocco. Electronic Publication     

Cys 618 Arg mutation in the RET proto-oncogene associated with familial medullary thyroid carcinoma and maternally transmitted Hirschsprung's disease suggesting a role for imprinting

The multiple endocrine neoplasia type 2 (MEN2) syndromes and Hirschsprung's disease (HSCR) are inherited neurocristopathies characterized by medullary thyroid carcinoma (MTC), pheochromocytoma, parathyroid disease, and gastrointestinal neuromatosis. Mutations in the RET proto-oncogene are the underlying cause of the MEN2 syndromes and some cases of HSCR. In this report, we show that Cys 618 Arg mutation cosegregates with familial MTC and HSCR in two Moroccan Jewish families in which no involvement of pheochromocytoma or parathyroidism was observed. A single haplotype shared by chromosomes bearing the Cys 618 Arg mutation in both families strongly suggests a founder effect for this mutation. We have observed in our and in several other previously reported families, an excess of maternal over paternal mutated RET alleles in offsprings affected by HSCR. We suggest that parental imprinting may play a role in the ethiology of HSCR caused by mutations in the RET protooncogene. Hum Mutat 10:155–159, 1997. © 1997 Wiley-Liss, Inc.     

Dominant optic atrophy in Denmark - report of 15 novel mutations in OPA1, using a strategy with a detection rate of 90 %

ABSTRACT: BACKGROUND: Investigation of the OPA1 mutation spectrum in autosomal dominant optic atrophy (ADOA) in Denmark. METHODS: Index patients from 93 unrelated ADOA families were assessed for a common Danish founder mutation (c.2826_2836delinsGGATGCTCCA) inOPA1. If negative, direct DNA sequencing of the coding sequence and multiplex ligation-dependent probe amplification (MLPA) were performed. Results from MLPA analysis have been previously reported. Haplotype analysis was carried out analysing single nucleotide polymorphisms (SNP). Retrospective clinical data were retrieved from medical files. RESULTS: Probably causative mutations were identified in 84 out of 93 families (90 %) including 15 novel mutations. Three mutations c.983A > G, c.2708_2711delTTAG and c.2826_2836delinsGGATGCTCCA, were responsible for ADOA in10, 11 and 28 families, respectively, corresponding to 11 %, 12 % and 30 %. A common haplotype in nine of ten c.983A > G families suggests that they descend from a single founder. The c.2708_2711delTTAG mutation was present on at least two haplotypes and has been repeatedly reported in various ethnic groups,thus represents a mutational hotspot. Clinical examinations of index patients with the two latter mutations demonstrated large inter- and intra-familial variations apparently. CONCLUSIONS: Genetic testing for OPA1mutations assist in the diagnosis. We have identified mutations in OPA1 in 90 % of families including 15 novel mutations. Both DNA sequencing and MLPA analysis are necessary to achieve a high detection rate. More than half of the affected families in Denmark are represented by three common mutations, at least two of which are due to a founder effect, which may account for the high prevalence of ADOA in Denmark.     

Prevalence of myotonic dystrophy in Israeli Jewish communities: inter-community variation and founder premutations

In a comprehensive epidemiological survey among Jews living in Israel, the average prevalence of myotonic dystrophy (DM) was 15.7/10(5) (1 case in 6369) with intercommunity variations; the Ashkenazi Jews had the lowest rate, 5.7/10(5) (1 case in 17544) as compared to the rate in the Sephardim/Oriental Jews 20/10(5) (1 case in 5000) and the in the Yemenite Jews 47.3/10(5) (1 case in 2114). The rate of unrelated DM-sibships per 10(6) people of each community was used as an estimate of the transition rate from stable to unstable DMPK-(CTG)(n) alleles assuming that each transition is a beginning of a new DM sibship. This study indicated that the difference in the incidence of DM is a result of higher mutation rate in the non-Ashkenazi Jews (>50/10(6)) as compared to the rate in the Ashkenazi Jews (16.3/10(6)). The intragenic haplotype of the DM alleles was the same as that of the DM in many populations all over the world. However, two DM closely linked markers D19S207 and D19S112 were in linkage disequilibrium with the DM mutation in patients of Yemenite and Moroccan (the largest subgroup in the Sephardim Jews) extractions and not in the Ashkenazi patients. This observation indicated a common ancestral origin for the DM premutation in patients of the same ethnic origin. We concluded that the difference in the prevalence of DM among the Jewish communities is a consequence of founder premutations in the non-Ashkenazi Jewish communities.     

Reconstruction of patrilineages and matrilineages of Samaritans and other Israeli populations from Y-chromosome and mitochondrial DNA sequence variation

The Samaritan community, which numbered more than a million in late Roman times and only 146 in 1917, numbers today about 640 people representing four large families. They are culturally different from both Jewish and non-Jewish populations in the Middle East and their origin remains a question of great interest. Genetic differences between the Samaritans and neighboring Jewish and non-Jewish populations are corroborated in the present study of 7,280 bp of nonrecombining Y-chromosome and 5,622 bp of coding and hypervariable segment I (HVS-I) mitochondrial DNA (mtDNA) sequences. Comparative sequence analysis was carried out on 12 Samaritan Y-chromosome, and mtDNA samples from nine male and seven female Samaritans separated by at least two generations. In addition, 18-20 male individuals were analyzed, each representing Ethiopian, Ashkenazi, Iraqi, Libyan, Moroccan, and Yemenite Jews, as well as Druze and Palestinians, all currently living in Israel. The four Samaritan families clustered to four distinct Y-chromosome haplogroups according to their patrilineal identity. Of the 16 Samaritan mtDNA samples, 14 carry either of two mitochondrial haplotypes that are rare or absent among other worldwide ethnic groups. Principal component analysis suggests a common ancestry of Samaritan and Jewish patrilineages. Most of the former may be traced back to a common ancestor in the paternally-inherited Jewish high priesthood (Cohanim) at the time of the Assyrian conquest of the kingdom of Israel.     

Mucolipidosis type IV: novel MCOLN1 mutations in Jewish and non-Jewish patients and the frequency of the disease in the Ashkenazi Jewish population

The gene MCOLN1 is mutated in Mucolipidosis type IV (MLIV), a neurodegenerative, recessive, lysosomal storage disorder. The disease is found in relatively high frequency among Ashkenazi Jews due to two founder mutations that comprise 95% of the MLIV alleles in this population [Bargal et al., 2000]. In this report we complete the mutation analysis of Jewish and non-Jewish MLIV patients whose DNA were available to us. Four novel mutations were identified in the MCOLN1 gene of severely affected patients: two missense, T232P and F465L; a nonsense, R322X; and an 11-bp insertion in exon 12. The nonsense mutation (R322X) was identified in two unrelated patients with different haplotypes in the MCOLN1 chromosomal region, indicating a mutation hotspot in this CpG site. An in-frame deletion (F408del) was identified in a patient with unusual mild psychomotor retardation. The frequency of MLIV in the general Jewish Ashkenazi population was estimated in a sample of 2,000 anonymous, unrelated individuals assayed for the two founder mutations. This analysis indicated a heterozygotes frequency of about 1/100. A preferred nucleotide numbering system for MCOLN1 mutations is presented and the issue of a screening program for the detection of high-risk families in the Jewish Ashkenazi population is discussed.