Congenital sensory neuropathy

A novel biallelic single base insertion in WNK1 in a Pakistani family with congenital insensitivity to pain

Hereditary sensory and autonomic neuropathy type II (HSANII) is a rare, recessively inherited neurological condition frequently involving insensitivity to pain. The subtype, HSAN2A, results from mutations in the gene WNK1. We identified a consanguineous Pakistani family with three affecteds showing symptoms of HSANII. We performed microarray genotyping, followed by homozygosity-by-descent (HBD) mapping, which indicated several significant HBD regions, including ~6 Mb towards the terminus of chromosome 12p, spanning WNK1. Simultaneously, we performed whole exome sequencing (WES) on one of the affected brothers, and identified a homozygous 1 bp insertion variant, Chr12:978101dupA, within exon 10. This variant, confirmed to segregate in the family, is predicted to truncate the protein (NM_213655.4:c.3464delinsAC; p.(Thr1155Asnfs*11) and lead to nonsense-mediated mRNA decay of the transcript. Previous studies of congenital pain insensitivity/HSANII in Pakistani families have identified mutations in SCN9A. Our study identified a previously unreported WNK1 mutation segregating with congenital pain insensitivity/HSANII in a Pakistani family.

WNK1/HSN2 isoform and the regulation of KCC2 activity

Hereditary sensory and autonomic neuropathy type 2 is a rare autosomal recessive pathology presenting with early onset peripheral sensory defects. It arises from mutations affecting a specific isoform of the WNK1 kinase (with-no-lysine protein kinase 1) termed WNK1/HSN2. The role of WNK1 in the nervous system is not well understood. In our recent paper, we examined the effect of a pathological loss-of-function of the Wnk1/Hsn2 isoform on the development of the peripheral nervous system of the zebrafish embryo. Upon Wnk1/Hsn2 silencing using antisense morpholino oligonucleotides, we observed defects in the development of the sensory peripheral lateral line (PLL). Phenotypical embryos were also found to overexpress RNA for potassium-chloride cotransporter 2 (KCC2), a downstream target of WNK1 phosphorylation. Injection of recombinant mRNA for active KCC2, but not for inactive mutant KCC2-C568A, replicated the PLL defects observed in wnk1/hsn2 deficient animals, suggesting an essential role for WNK1/HSN2 in KCC2 regulation.

WNK1/HSN2 mutation in human peripheral neuropathy deregulates KCC2 expression and posterior lateral line development in zebrafish (Danio rerio)

Hereditary sensory and autonomic neuropathy type 2 (HSNAII) is a rare pathology characterized by an early onset of severe sensory loss (all modalities) in the distal limbs. It is due to autosomal recessive mutations confined to exon "HSN2" of the WNK1 (with-no-lysine protein kinase 1) serine-threonine kinase. While this kinase is well studied in the kidneys, little is known about its role in the nervous system. We hypothesized that the truncating mutations present in the neural-specific HSN2 exon lead to a loss-of-function of the WNK1 kinase, impairing development of the peripheral sensory system. To investigate the mechanisms by which the loss of WNK1/HSN2 isoform function causes HSANII, we used the embryonic zebrafish model and observed strong expression of WNK1/HSN2 in neuromasts of the peripheral lateral line (PLL) system by immunohistochemistry. Knocking down wnk1/hsn2 in embryos using antisense morpholino oligonucleotides led to improper PLL development. We then investigated the reported interaction between the WNK1 kinase and neuronal potassium chloride cotransporter KCC2, as this transporter is a target of WNK1 phosphorylation. In situ hybridization revealed kcc2 expression in mature neuromasts of the PLL and semi-quantitative RT-PCR of wnk1/hsn2 knockdown embryos showed an increased expression of kcc2 mRNA. Furthermore, overexpression of human KCC2 mRNA in embryos replicated the wnk1/hsn2 knockdown phenotype. We validated these results by obtaining double knockdown embryos, both for wnk1/hsn2 and kcc2, which alleviated the PLL defects. Interestingly, overexpression of inactive mutant KCC2-C568A, which does not extrude ions, allowed a phenocopy of the PLL defects. These results suggest a pathway in which WNK1/HSN2 interacts with KCC2, producing a novel regulation of its transcription independent of KCC2's activation, where a loss-of-function mutation in WNK1 induces an overexpression of KCC2 and hinders proper peripheral sensory nerve development, a hallmark of HSANII.

KIF1A, an axonal transporter of synaptic vesicles, is mutated in hereditary sensory and autonomic neuropathy type 2

Hereditary sensory and autonomic neuropathy type II (HSANII) is a rare autosomal-recessive disorder characterized by peripheral nerve degeneration resulting in a severe distal sensory loss. Although mutations in FAM134B and the HSN2 exon of WNK1 were associated with HSANII, the etiology of a substantial number of cases remains unexplained. In addition, the functions of WNK1/HSN2 and FAM134B and their role in the peripheral nervous system remain poorly understood. Using a yeast two-hybrid screen, we found that KIF1A, an axonal transporter of synaptic vesicles, interacts with the domain encoded by the HSN2 exon. In parallel to this screen, we performed genome-wide homozygosity mapping in a consanguineous Afghan family affected by HSANII and identified a unique region of homozygosity located on chromosome 2q37.3 and spanning the KIF1A gene locus. Sequencing of KIF1A in this family revealed a truncating mutation segregating with the disease phenotype. Subsequent sequencing of KIF1A in a series of 112 unrelated patients with features belonging to the clinical spectrum of ulcero-mutilating sensory neuropathies revealed truncating mutations in three additional families, thus indicating that mutations in KIF1A are a rare cause of HSANII. Similarly to WNK1 mutations, pathogenic mutations in KIF1A were almost exclusively restricted to an alternatively spliced exon. This study provides additional insights into the molecular pathogenesis of HSANII and highlights the potential biological relevance of alternative splicing in the peripheral sensory nervous system.

Thermosensory and mechanosensory perception in human genetic disease

Peripheral sensory perception is established through an elaborate network of specialized neurons that mediate the translation of extraorganismal stimuli through the use of a broad array of receptors and downstream effector molecules. Studies of human genetic disorders, as well as mouse and other animal models, have identified some of the key molecules necessary for peripheral innervation and function. These findings have, in turn, yielded new insights into the developmental networks and homeostatic mechanisms necessary for the transformation of external stimuli into interpretable electrical impulses. In this review, we will summarize and discuss some of the genes/proteins implicated in two particular aspects of sensory perception, thermosensation and mechanosensation, highlighting pathways whose perturbation leads to both isolated and syndromic sensory deficits.

Mutations in the nervous system--specific HSN2 exon of WNK1 cause hereditary sensory neuropathy type II

Hereditary sensory and autonomic neuropathy type II (HSANII) is an early-onset autosomal recessive disorder characterized by loss of perception to pain, touch, and heat due to a loss of peripheral sensory nerves. Mutations in hereditary sensory neuropathy type II (HSN2), a single-exon ORF originally identified in affected families in Quebec and Newfoundland, Canada, were found to cause HSANII. We report here that HSN2 is a nervous system-specific exon of the with-no-lysine(K)-1 (WNK1) gene. WNK1 mutations have previously been reported to cause pseudohypoaldosteronism type II but have not been studied in the nervous system. Given the high degree of conservation of WNK1 between mice and humans, we characterized the structure and expression patterns of this isoform in mice. Immunodetections indicated that this Wnk1/Hsn2 isoform was expressed in sensory components of the peripheral nervous system and CNS associated with relaying sensory and nociceptive signals, including satellite cells, Schwann cells, and sensory neurons. We also demonstrate that the novel protein product of Wnk1/Hsn2 was more abundant in sensory neurons than motor neurons. The characteristics of WNK1/HSN2 point to a possible role for this gene in the peripheral sensory perception deficits characterizing HSANII.

Novel mutation in the HSN2 gene in a Korean patient with hereditary sensory and autonomic neuropathy type 2

Hereditary sensory and autonomic neuropathies (HSAN) are a group of clinically and genetically heterogeneous disorders that are associated with sensory dysfunction. Among these, HSAN type 2 (HSAN2; MIM 201300) is a rare recessive disease that is characterized by an early age of onset with distal and proximal sensory loss, dysfunction of the autonomic nervous system, loss of the tendon reflex, the presence of various mutilations, and the slow progression of the disease over time. The authors report a Korean patient with the clinical features of HSAN2, who was compound heterozygous for two loss-of-function mutations in the HSN2 gene: c.217C > T (Gln73X) and c.1134_1135insT (Asp379fsX1). The Gln73X mutation was a novel mutation while the Asp379fsX1 mutation has recently been reported in a Japanese patient with HSAN2. These results expanded the spectrum of mutations of the HSN2 gene by identifying a novel truncating mutation in a Korean patient and further support the hypothesis that HSN2 is a causative gene for HSAN2.

A mutation in the HSN2 gene causes sensory neuropathy type II in a Lebanese family

Hereditary sensory and autonomic neuropathy (HSAN) type II is an autosomal recessive disorder clinically characterized by distal and proximal sensory loss that is caused by the reduction or absence of peripheral sensory nerves. Recently, a novel gene called HSN2 has been found to be the cause of HSAN type II in five families from Newfoundland and Quebec. Screening of this gene in an HSAN type II Lebanese family showed a 1bp deletion mutation found in a homozygous state in all affected individuals. This novel mutation supports the hypothesis that HSN2 is the causative gene for HSAN type II.

Hereditary sensory neuropathies

PURPOSE OF REVIEW

The hereditary sensory neuropathies, also known as the hereditary sensory and autonomic neuropathies, are a clinically and genetically heterogeneous group of disorders. As they are not as common as Charcot-Marie-Tooth disease, they do not receive the same level of attention, but there have been major advances in the identification of the causative genes in the past decade. Certain forms of hereditary sensory and autonomic neuropathy, especially hereditary sensory and autonomic neuropathy type I, which has minimal autonomic involvement and is more accurately termed hereditary sensory neuropathy type I, can present in a very similar fashion to certain forms of Charcot-Marie-Tooth disease (Charcot-Marie-Tooth type 2B, see below), and therefore it is important that clinicians who regularly manage patients with neuropathy are familiar with the latest developments in the hereditary sensory and autonomic neuropathies. This review will concentrate on the recent genetic advances in hereditary sensory and autonomic neuropathy, and especially on those forms that overlap clinically with Charcot-Marie-Tooth disease, hence the title of the review 'Hereditary sensory neuropathies' rather than hereditary sensory and autonomic neuropathies.

Cutaneous and sympathetic denervation in neonatal rats with a mutation in the delta subunit of the cytosolic chaperonin-containing t-complex peptide-1 gene

The mutilated-foot rat (mf rat) is an autosomal recessive mutant with characteristic digit deformities in adult animals, and this phenotype mimics many aspects of human sensory neuropathy. The genetics of mf rats was recently elucidated. To understand whether the genotype is responsible for cutaneous denervation before clinically overt mutilation in adult mf rats, we investigated skin innervation in postnatal day 7 (P7) mf rats and compared the patterns with P7 wild-type rats. The mf rat carries a G-->A mutation in the gene encoding the delta subunit of the cytosolic chaperonin-containing t-complex peptide-1 (Cct4). In the footpad skin of P7 mf rats, there was a >90% loss of epidermal nerves (0.7-7.9% of P7 wild-type rats) as indicated by neuronal markers including protein gene product 9.5 (PGP 9.5), growth-associated protein 43 (GAP43), calcitonin gene-related peptide (CGRP), and substance P (SP). The epidermis of hairy skin in hind feet was completely denervated in mf rats as well. Compared with an approximately 80% reduction in the size of dermal nerve fascicles and a parallel loss of nerve fibers, the nearly complete absence of epidermal innervation suggests further sensory nerve degeneration at the level of nerve terminals in the epidermis. In contrast, the loss of epidermal nerves in the abdominal skin of mf rats was less extensive than that in the footpad skin of mf rats; CGRP (+) and SP (+) fibers were moderately reduced (28.3-56.4% of levels of wild-type rats) with normal amounts of PGP 9.5 (+) and GAP43 (+) nerves. Sympathetic innervation as assessed by tyrosine hydroxylase immunoreactivity was absent from the footpad and abdominal skin of mf rats. In conclusion, there is regional skin denervation with diffuse sympathetic denervation in P7 mf rats. These results suggest that the mutation in Cct4 underlies cutaneous nerve degeneration in mf rats.

Identification of a novel gene (HSN2) causing hereditary sensory and autonomic neuropathy type II through the Study of Canadian Genetic Isolates

Hereditary sensory and autonomic neuropathy (HSAN) type II is an autosomal recessive disorder characterized by impairment of pain, temperature, and touch sensation owing to reduction or absence of peripheral sensory neurons. We identified two large pedigrees segregating the disorder in an isolated population living in Newfoundland and performed a 5-cM genome scan. Linkage analysis identified a locus mapping to 12p13.33 with a maximum LOD score of 8.4. Haplotype sharing defined a candidate interval of 1.06 Mb containing all or part of seven annotated genes, sequencing of which failed to detect causative mutations. Comparative genomics revealed a conserved ORF corresponding to a novel gene in which we found three different truncating mutations among five families including patients from rural Quebec and Nova Scotia. This gene, termed "HSN2," consists of a single exon located within intron 8 of the PRKWNK1 gene and is transcribed from the same strand. The HSN2 protein may play a role in the development and/or maintenance of peripheral sensory neurons or their supporting Schwann cells.

[Hereditary sensory and autonomic neuropathy type 2: two cases report]

Two cases of hereditary sensory and autonomic neuropathy type 2 are reported. This type of neuropathy is included in a group that consists of five different entities. The systematization of that neuropathies depends on multiple criteria such as age of beginning, genetic aspects, clinical manifestations, eletroneuromyographic and pathologic features. In this report we describe the cases in a family, two brothers, 27 and 35 years old that were observed in our department with pain insensibility and consequent sensitive-trophic disturbs and deformity of members. The diagnoses was defined as hereditary sensory and autonomic neuropathy type 2 and an inherited pattern recessive autossomic transmission was considered. The age of beginning, the hereditary aspects, the clinical manifestations and the eletroneuromyographic features are analysed. The differential diagnoses with other sensory hereditary and acquired neuropathies is emphasized.

Cervical disc herniation in a patient with congenital insensitivity to pain: a case report

STUDY DESIGN

A case report of a patient with a known diagnosis of congenital insensitivity to pain who developed a herniated cervical disc.

OBJECTIVES

To study the clinical manifestations of cervical radiculopathy in a patient with congenital insensitivity to pain and the long-term outcome after surgical treatment.

SUMMARY OF BACKGROUND DATA

There have been no reports in the English literature documenting such a patient.

METHODS

Retrospective case report and long-term clinical and radiographic follow-up.

RESULTS

This patient with a known diagnosis of congenital insensitivity to pain had neurologic motor weakness with "neck and shoulder pain." Clear radicular pattern could not be elicited. The patient underwent a successful anterior discectomy and fusion with long-term clinical and radiographic results.

CONCLUSION

Patients with congenital insensitivity to pain who develop a cervical disc herniation may present with atypical symptoms not manifesting in the classic radicular pattern. Higher index of suspicion by the clinician must be practiced to make the appropriate diagnosis. Successful surgical outcome may be achieved in these patients.

Congenital indifference to pain

Congenital analgesia can vary from simple analgesia without any systemic dysfunction to more serious conditions associated with peripheral neuropathy, self-mutilation, and mental retardation. Prevention of injury is important for normal growth of the child.

Exclusion of p75NGFR and other candidate genes in a family with hereditary sensory neuropathy type II

Hereditary sensory neuropathy Type II (HSN II) is an autosomal recessive disorder characterized by the loss of peripheral sensory modalities in individuals with otherwise normal development. Patients with HSN II often have chronic ulceration of the fingers and toes, autoamputation of the distal phalanges, and neuropathic joint degeneration associated with loss of pain sensation. Recent descriptions of a similar phenotype in mice carrying a targeted mutation in the low affinity nerve growth factor receptor, p75NGFR, suggested the possibility that mutations in this gene or other members of the nerve growth factor (NGF) family of genes and their receptors might be responsible for this human disorder. In this study candidate genes were evaluated by their inheritance pattern in two sisters affected with HSN II, their unaffected sister and mother in a consanguineous family. The segregation of polymorphic alleles at and around loci for p75NGFR, TRKA, TRKB, BDNF, and familial dysautonomia (another hereditary sensory neuropathy having features in common with HSN II) virtually excluded these genes as the cause of HSN II in this family. Further evaluation of loci for other neurotrophic factors and their receptors, which will be possible when mapping information on their loci becomes available, may permit the identification of the gene responsible for HSN II.

Peripheral neuropathy and peripheral nerve injury

The peripheral nerves to the bladder can be altered by several disease processes. Voiding symptoms alone are not reliable in predicting the exact neurogenic bladder dysfunction. Urodynamic evaluation is crucial to optimize therapy and to rule out concomitant pathology.

The congenital insensitivity-to-pain syndrome (analgesia congenita): report of a case

The congenital insensitivity-to-pain syndrome is one of several entities of sensory neuropathies in which pain sensation is absent from birth. This report describes a female child with the syndrome, who in all other aspects was normal. The most severe oral consequence of her disorder was self-inflicted exfoliation at an early age of all single-rooted primary teeth and one primary molar (a total of 13 teeth). The child was monitored from age 8. The primary aim in management was to monitor the eruption of the permanent teeth and occlusal development. At eruption of the mandibular incisors a protective splint was constructed to prevent their sharp edges injuring the tongue and the oral mucosa. The child was also instructed not to agitate her newly erupted teeth. Further occlusal development of the permanent dentition was uneventful.

Post-rhizotomy periodontal atrophy

This report details the experience of two people who suffered a unique type of periodontal atrophy following trigeminal sensory rhizotomy. The cause is unknown but it may be the result of unintentional self-mutilation.

Congenital insensitivity to pain: a 20 year follow up

The exact nosological status of "congenital insensitivity to pain" remains in doubt. Possible pathological correlates of this clinical syndrome include sensory neuropathy, central lesions at the level of the reticular formation or dorsal horn of the spinal cord, or a central indifference to, or asymbolia for, pain. The reassessment of two members of a kindred previously reported more than 20 years ago as having congenital insensitivity to pain indicated that they in fact had an inherited sensory and autonomic neuropathy. Prolonged follow up and morphometric analysis of sequential nerve biopsies may be necessary to definitively establish this diagnosis.

Hereditary sensory neuropathies

Hereditary sensory neuropathies have not shared in the major advances that have taken place in the molecular genetics of the hereditary demyelinating motor and sensory neuropathies. Thus far, classification depends upon their mode of inheritance and clinical features. The delineation of the various clinical syndromes is still not complete. This is a necessary preliminary to establishing the genetic basis of these neuropathies. The hereditary sensory neuropathies can be accordingly grouped into those with predominantly sensory and some associated autonomic features and those in which a sensory neuropathy is part of a spinocerebellar degeneration or other multisystem degeneration.

Nonprogressive type II hereditary sensory autonomic neuropathy: a homogeneous clinicopathologic entity

Two different clinical subtypes were previously identified within hereditary sensory autonomic neuropathy (HSAN) type II: a stable congenital form and a progressive one. This paper discusses two clinicopathologic cases of nonprogressive HSAN type II with morphometric correlations. In addition, a retrospective literature search was carried out to locate other cases where an accurate histologic examination, including ultrastructural features, was available in order to relate clinical and pathologic aspects of the disease. The combined data support the individualization of this neuropathic form as a homogeneous disease, as has been suggested during the last century and underline the clinical importance of this concept for the prognosis and investigation of sensory, auditory, autonomic, and motor functions in children with sensory neuropathies.

Autonomic involvement in inherited neuropathies

The inherited peripheral neuropathies constitute a large group of disorders, in some of which the causative metabolic defect has been identified whereas in the majority it is still unknown. Amongst the former, autonomic involvement is an important component in porphyric neuropathy, in the familial amyloid polyneuropathies, in Fabry's disease and in dopamine beta-hydroxylase deficiency. The latter group includes the hereditary sensory and autonomic neuropathies in some of which, such as the Riley-Day syndrome, autonomic disturbances are prominent, whereas in others they constitute only a minor component of the symptomatology. Autonomic dysfunction is an important component of the neurological manifestations in multiple endocrine neoplasia type IIB.

Congenital sensory neuropathy. Ophthalmological implications

The authors examined a patient presenting with congenital sensory neuropathy with selective loss of small myelinated nerve fibres. The appearance of (bilaterial) keratitis or corneal ulceration in early childhood is strongly suggestive of congenital corneal anaesthesia. Concomitant symptoms such as anisocoria, abnormal pupillary reaction, diminished tear production and disturbed sensibility to pain and temperature point to a generalized disease: one of the hereditary sensory and autonomic neuropathies. In order to establish a definite diagnosis, elaborate neurological examination, including ultrastructural study of a muscle-nerve biopsy, is required. Tarsorrhaphy, therapeutic flushfitting PMMA scleral lenses and hydrophilic HEMA contact lenses are advocated, in order to protect the cornea. The results with high-water-content hydrophilic contact lenses are promising, those of keratoplasty limited.

Dysesthesias and self-mutilation in humans and subhumans: a review of clinical and experimental studies

The chronic deafferentation syndrome includes a complex pattern of abnormal self-directed behavior and a stress response. Subhuman self-mutilation is a secondary consequence of the chronic deafferentation syndrome. The evidence indicates that the chronic deafferentation syndrome in subhumans is a valid model for the induced and the spontaneous dysesthesias in humans. Objective criteria for the definition of subhuman dysesthesias have been derived from independent sources of evidence, in neurally intact subjects; those criteria are then found to match the subhuman syndrome of deafferentation. Support for the validity of the inference of subhuman dysesthesias derives from the parallels with the various facts of the human dysesthesias. The credibility of this argument is significantly strengthened by reports of morphological and excitatory physiological abnormalities, in central somatosensory structures, in response to deafferentation. There is no independent subhuman evidence in support of alternate interpretations of the deafferentation syndrome, and those interpretations seem to be inadequate in several aspects. Doubts concerning the validity of this animal model have been allayed by reports of dysesthesias in humans with spinal posterior rhizotomies or ganglionectomies, and also those with congenital analgesia. Moreover, the occurrence of this syndrome in hypoalgesic areas as a consequence of anterolateral cordotomy in monkeys, can best be interpreted as a reflection of dysesthesias. This syndrome is released by neuropathological or neurosurgical lesions in the peripheral or central nervous system; lesions which involve small caliber peripheral afferents or the spinothalamic tract. Variability in the release of this syndrome has been associated with several different factors. So far, the chronic syndrome is intractable. Evidence relates the abnormalities of this syndrome to pathophysiological foci in central relays of the somatosensory system, and suggests that the chronic abnormalities of this syndrome can be sustained at brain levels.

Reduced substance P in hereditary sensory neuropathy in the mf rat

Mutilated foot (mf) is a mutant rat with an autosomal recessive sensory neuropathy. Affected animals become ataxic and their feet become mutilated. Morphological and quantitative studies have shown a reduced number of sensory ganglion cells and of cells of secondary sensory neurons. No degeneration was seen in the peripheral nervous system. Substance P (SP) is an undecapeptide which is thought to be involved in transmission of nociceptive information. Since mf rats show, in addition to ataxia, a decreased response to painful stimuli, SP immunoreactivity was examined. The density of SP staining was decreased at all levels of the spinal cord, mainly at cervical and lumbar levels and only in areas related to sensory pathways. In other areas of the spinal cord and in the substantia gelatinosa of the trigeminal tract, no reduction of SP staining was observed. The results further support the relationship between SP and transmission of pain stimuli. There are also many similarities between the appearance in mf rats and those in animals in which sensory afferents from dorsal root ganglia had been impaired with various methods, particularly in those treated from birth with capsaicin.

Positive bethanechol chloride supersensitivity test in hereditary sensory neuropathy

An 11-year-old girl with hereditary sensory neuropathy (type II) presented with neurogenic bladder disease. Urodynamic evaluation revealed a sensory neurogenic bladder and a markedly positive bethanechol chloride supersensitivity test. This case report supports Lapides' original observation that a positive bethanechol chloride supersensitivity test may occur in pure sensory neurogenic bladder disease.

Autosomal recessive peripheral sensory neuropathy in 3 non-Ashkenazi Jewish families

Three unrelated Oriental Jewish families with a total of eight subjects with progressive hereditary sensory neuropathy are reported. The parents were all unaffected and because of parental consanguinity in each of the three families it is postulated that this rare neurological disorder is transmitted in an autosomal recessive manner. In one family both parents showed an abnormal response to pain stimulation with normal motor and sensory nerve conduction velocity. This response may be an expression of the carrier state for this hereditary disease. Only five other families (non-Jewish) have been reported as having this form of peripheral hereditary sensory neuropathy. These observations suggest that one type, the progressive form, of peripheral hereditary sensory neuropathy may be more common in Oriental Jews.

Oral manifestations of the congenital insensitivity-to-pain syndrome

The congenital insensitivity-to-pain syndrome is a sensory syndrome in which pain is impaired. It has been variably classified under a variety of terms, on occasion leading to some confusion. The condition is present at birth. The patient is usually, but not always, normal with respect to intelligence, development, and psychological adjustments. Other sensory perceptions are normal. Traumatic lesions as a result of self-mutilative acts are not uncommon, especially at an early age. The condition may not be apparent clinically until the time of initial tooth eruption. As the primary teeth erupt, the patient acquires the necessary apparatus for self-infliction of wounds to oral structures, skin, and fingernails. A case of congenital indifference to pain is presented, with clinical documentation of tooth-related problems occurring over a 2-year period and of the steps taken to correct or minimize the traumatic effects of chewing.

A new variety of hereditary sensory neuropathy

A pedigree with a new form of hereditary sensory neuropathy is described. Ataxia and scoliosis rather than loss of pain and ulcerating acropathy are the principal clinical feature. Analysis of the pedigree suggests a dominant mode of transmission with variable age of onset and perhaps reduced penetrance.

Recessive hereditary sensory neuropathy

Clinical features in 2 cases of a recessive form of hereditary sensory neuropathy and the light and electron microscopy of sural nerve biopsy in 1 of them are described. The patients showed symptoms typical of this form of the disease; it should be stressed however that the loss of cutaneous sensation appeared to be limited to the distal parts of the lower extremities and involved all modalities of cutaneous sensation. Histological examination of sural nerve revealed a marked reduction in the number of myelinated fibres due to Wallerian-like axonal degeneration, of which various stages were represented. In addition, segmental demyelination, probably secondary to axonal changes, was seen. The unmyelinated fibres were also involved but to a lesser degree than the myelinated fibres. The observations indicate a progressive nature of the pathological process.

Soradic ulcerative mutilating acropathy with imbalance of free amino acids in the cerebrospinal fluid

A case of sporadic ulcerative mutilating acropathy is described. Muscle biopsy showed signs of neurogenic atrophy. Motor nerve conduction velocity was slightly reduced. The muscles of the foot were completely unresponsive to electric stimulation of both femoral nerves. The content of free amino acids in serum and cerebrospinal fluid was determined by ion exchange chromatography, and compared with a control group. While in serum no significant changes were found, in CSF most amino acids showed great alterations, mainly consisting in an increase. It is suggested that the primary disturbance may be located in the spinal nerve roots.