Serine and Lipid Metabolism in Macular Disease and Peripheral Neuropathy

BACKGROUND

Identifying mechanisms of diseases with complex inheritance patterns, such as macular telangiectasia type 2, is challenging. A link between macular telangiectasia type 2 and altered serine metabolism has been established previously.

METHODS

Through exome sequence analysis of a patient with macular telangiectasia type 2 and his family members, we identified a variant in SPTLC1 encoding a subunit of serine palmitoyltransferase (SPT). Because mutations affecting SPT are known to cause hereditary sensory and autonomic neuropathy type 1 (HSAN1), we examined 10 additional persons with HSAN1 for ophthalmologic disease. We assayed serum amino acid and sphingoid base levels, including levels of deoxysphingolipids, in patients who had macular telangiectasia type 2 but did not have HSAN1 or pathogenic variants affecting SPT. We characterized mice with low serine levels and tested the effects of deoxysphingolipids on human retinal organoids.

RESULTS

Two variants known to cause HSAN1 were identified as causal for macular telangiectasia type 2: of 11 patients with HSAN1, 9 also had macular telangiectasia type 2. Circulating deoxysphingolipid levels were 84.2% higher among 125 patients with macular telangiectasia type 2 who did not have pathogenic variants affecting SPT than among 94 unaffected controls. Deoxysphingolipid levels were negatively correlated with serine levels, which were 20.6% lower than among controls. Reduction of serine levels in mice led to increases in levels of retinal deoxysphingolipids and compromised visual function. Deoxysphingolipids caused photoreceptor-cell death in retinal organoids, but not in the presence of regulators of lipid metabolism.

CONCLUSIONS

Elevated levels of atypical deoxysphingolipids, caused by variant SPTLC1 or SPTLC2 or by low serine levels, were risk factors for macular telangiectasia type 2, as well as for peripheral neuropathy. (Funded by the Lowy Medical Research Institute and others.).

Hereditary Sensory and Autonomic Neuropathy Presenting With Mutilating Trophic Ulcers

Two siblings, a 19-year-old woman and an 18-year-old man, born to apparently normal parents of second-degree consanguineous marriage, presented to the Department of Dermatology, Sawai Man Singh Medical College Hospital, Jaipur, India, with recurrent skin ulcers of the hands and feet since early childhood. The ulcers were spontaneous, slow to heal, and caused deformities. On initial examination, they were found to have distal sensory loss, predominantly to pain and temperature. The patients were diagnosed with hereditary sensory and autonomic neuropathy of ulceromutilating type (Type 2) based on clinical evidences, nerve studies, and neuropathology. Although clinical features were distinct, due to slow progression of the disease and lack of clinical suspicion, diagnosis was delayed until adulthood when complications developed leading to deformities. Through this report, the authors intend to familiarize readers with this rare disease that can present with trophic ulcers.

Classification of Systemic and Localized Sweating Disorders

Hyperhidrosis can be subdivided into generalized hyperhidrosis, with increased sweating over the entire body, and focal hyperhidrosis, in which the excessive sweating is restricted to specific parts of the body. Generalized hyperhidrosis may be either primary (idiopathic) or secondary. Secondary generalized hyperhidrosis may be caused by infections such as tuberculosis, hyperthyroidism, endocrine and metabolic disturbances such as pheochromocytoma, neurological disorders, or drugs. Focal hyperhidrosis may also be primary (idiopathic) or secondary. Frey's syndrome is one form of secondary focal hyperhidrosis that occurs during eating together with reddening of the area in front of the ear following parotid gland surgery or injury. Primary focal hyperhidrosis is particularly common on the palms and soles of the feet, in the axilla, and on the head. Anhidrosis may be either congenital/genetic or acquired. Some of the most typical forms of congenital/genetic anhidrosis include hypohidrotic ectodermal dysplasia, congenital insensitivity to pain and anhidrosis, and Fabry disease. Acquired anhidrosis is classified as secondary anhidrosis, which may be due to an underlying disorder such as a neurological disorder, an endocrine or metabolic disturbance, or the effect of drugs, or idiopathic anhidrosis for which the pathology, cause, and mechanism are unknown. Idiopathic anhidrosis is classified into acquired idiopathic generalized anhidrosis (AIGA), idiopathic segmental anhidrosis, and Ross syndrome. AIGA is divided into three categories according to differences in the site of disturbance: (1) sudomotor neuropathy, (2) idiopathic pure sudomotor failure, and (3) sweat gland failure.

Novel and novel de novo mutations in NTRK1 associated with congenital insensitivity to pain with anhidrosis: a case report

Congenital insensitivity to pain with anhidrosis (CIPA) is a very rare autosomal recessively inherited disorder. The main clinical features of the disorder consist of absence of reactions to noxious stimuli and inability to sweat under any conditions.In this case report, a 3-year-old Chinese boy diagnosed with CIPA presented with the core features of CIPA, including insensitivity to noxious stimuli, self-mutilation, inability to sweat, and developmental delay. Clinical and genetic analyses were conducted on the affected boy.Sequencing analysis revealed an inherited novel mutation, c.1635G>C, and a novel de novo mutation, c.2197G>A, in the NTRK1 gene. In silico studies suggested that the mutations described are detrimental to the function of the protein encoded by the NTRK1 gene.The two novel mutations described here widen the genetic spectrum of CIPA, and this knowledge will benefit studies addressing this disease and pain medicine in the future.

Anesthetic management of a patient with congenital insensitivity to pain: a case report

Pain protects the body from damaging effects of harmful stimuli. Congenital insensitivity to pain is a rare inherited disorder characterized by diminished or absent sensitivity to pain, touch, and pressure that leads to frequent trauma and self-mutilation. The disorder is part of the hereditary sensory and autonomic neuropathy (HSAN) family, in which 5 types have been recognized. Research and case reports of anesthetic risks and analgesic needs of these patients is limited due to the infrequent nature of the disorder. Recommendations for anesthesia include modification of intraoperative opioid requirements, use of anesthetics to ensure cooperation and immobility, and intraoperative temperature monitoring. It is imperative for anesthesia providers to understand which type of HSAN their patient experiences and to conduct a thorough preoperative interview because a different interpretation of sensory loss may occur in each HSAN category. This article reports the case of a patient with HSAN type 2 who presented for knee arthroscopy.

Old fractures in two patients with congenital insensitivity to pain with anhidrosis: radiological findings

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive disease that is characterized by anhidrosis, insensitivity to noxious stimuli, and mental retardation. Patients who suffer from CIPA easily sustain injuries due to pain insensitivity. Radiological findings in two CIPA patients revealed several old fractures of which the patients were unaware of previous injury. An early diagnosis of CIPA is important for the prevention and treatment of various complications. Our data indicate that radiological findings may provide important information for the diagnosis of CIPA.

Bisphosphonate therapy for painless fracture: change of HSAN 1 clinical course with biphosphonate and Vitamin D therapy

Hereditary Sensory and Autonomic Neuropathies comprise a set of 5 rare neurologic conditions, little known to radiologists as the neurologic and skin abnormalities precede the radiographic changes by months or even years. We report a Caucasian patient with a clinical history of HSAN, most consistent with subtype 1, whose progressive, destructive bone changes of the foot were not only controlled but to a degree reversed by the administration of bisphosphonates (Alendronate ) and vitamin D (Colecalciferol). The authors believe that combined bisphosphonate and vitamin D therapy is the treatment of choice for progressive bony changes in HSAN1. This therapy may be beneficial in other neuropathic osteoarthropathies and possibly osteolytic bone disorders.

[Congenital corneal anesthesia. A case report]

Congenital corneal anesthesia (CCA) is an uncommon condition difficult to diagnose. We report the case of a 4-year-old girl who presented with bilateral congenital corneal anesthesia revealed by a corneal ulcer which had been unresponsive to adapted local treatment. Self-inflicted corneal injuries were present. It is important to search for corneal anesthesia in children with chronic ulceration of the cornea and selfinflicted injuries.

Recurrent fatal necrotizing fasciitis due to Streptococcus pyogenes in a child with hereditary sensory and automic neuropathy type IV

Although necrotizing fasciitis (NF) is a rapidly progressive infection, recurrent NF is very rare. Herein we report a rare case of recurrent NF due to Streptococcus pyogenes. A 12-year-old female with hereditary sensory and autonomic neuropathy (HSAN) type IV presented with fever and swelling on her left knee. NF was diagnosed and she was treated successfully. Two years later she was readmitted with NF of the right knee and limb. Despite treatment, progressive tissue necrosis developed and proximal femur amputation was performed. Eight months following the second attack she was readmitted with NF of her left knee and her entire leg. Despite a wide surgical debridement and antibiotic treatment, the clinical status of the patient failed to improve and she subsequently died. Although many conditions have been reported to be predisposing factors for NF, this is the first report of an association between HSAN type IV and recurrent NF due to S. pyogenes. We recommend antibiotic prophylaxis for patients with NF due to S. pyogenes, especially for those with predisposing factors.

Risk of aspiration during anesthesia in patients with congenital insensitivity to pain with anhidrosis: case reports and review of the literature

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive disease, characterized by episodes of unexplained fever, anhidrosis, pain insensitivity despite intact tactile perception, self-mutilating behavior, mental retardation, and autonomic nervous system (ANS) abnormalities. We present a case series of three patients with CIPA who underwent semielective orthopedic surgery under general anesthesia complicated by intraoperative regurgitation, and subsequent aspiration in two of the three cases. All three patients were nil per os (NPO) for at least 8 h prior to surgery. Two patients had their airways maintained with a laryngeal mask airway (LMA), and one patient had an endotracheal tube (ETT). The patients with an LMA suffered aspiration of gastric contents and subsequently developed hypoxic cardiac arrest. Although the patient with an ETT in situ regurgitated intraoperatively, the presence of the ETT prevented aspiration and any further potential complications. We review the perioperative complications typically observed in patients with CIPA and discuss the risks of using an LMA in these patients. We recommend that patients with CIPA always should be considered as having a "full stomach", regardless of the duration of their NPO status, due to their coexisting ANS abnormalities. Therefore, rapid-sequence induction with an ETT should be utilized for the anesthetic management in every patient with CIPA.

Dental management of oral self-mutilation in neurological patients: a case of congenital insensitivity to pain with anhidrosis

Hereditary sensory and autonomic neuropathy type IV is a rare disease characterized by fever episodes, mental retardation of different intensity, recurrent episodes of fever secondary to anhidrosis, little or no perspiration and congenital insensitivity to pain. Oral self-mutilation is also a characteristic sign. In this article, we present the case of an infant, aged 22 months, who showed these clinical characteristics and was treated with a dental device to prevent the patient from injuring her tongue. This device consisted of two acrylic splints joined at the back in the posterior sector, it provided an anterior open bite and allowed the infant to breathe through her mouth. The lesions of the patient had improved after using the device but the patient died due to the medical problem. Neuropathies treatment is a great challenge for medical teams. Dentists should form part ot these teams because of the bucal implications that may appear. Different appliances can be designed in order to solve the special problems each case may present.

[Hand involvement in Thevenard's disease: a new "phlegmonous" form. An exceptional case report]

Thévenard's disease is a rare familial ulcero-mutilating acropathology involving the peripheral nervous system. It typically begins on the feet and only rarely spreads to the hands late in the course of the disease. It first causes cutaneous ulcerations and then secondary osseous deformations and osteoarticular destruction, due to a distal loss of temperature sensation. We report the case of an 87 year old patient who suffered from a particular clinical form, undescribed as yet in the literature and characterized by local and general superinfections predominately on the hands. We term this the "cellulitic" presentation or form of Thévenard's disease.

Hereditary neuropathy with liability to pressure palsies and anaesthesia: peri-operative nerve injury

A 43-year-old female with carcinoma of the left breast underwent wide local excision of the tumour and sentinel lymph node biopsy under general anaesthesia. Three lymph nodes were removed uneventfully during the operation. Postoperatively, the patient complained of weakness and decreased sensation of her left arm. A diagnosis of peri-operative neuropraxia was made. This resolved completely over the following 4 weeks. Genetic testing confirmed a diagnosis of hereditary neuropathy with liability to pressure palsies.

Ocular manifestations of congenital insensitivity to pain with anhidrosis

PURPOSE

To describe ocular manifestations in Japanese patients with congenital insensitivity to pain with anhidrosis (CIPA), focusing particularly on the status of the ocular surface.

DESIGN

Observational case series.

METHODS

Eighteen patients with CIPA underwent applicable ophthalmologic examinations, including visual acuity, refraction, slit-lamp examination, fundus examination, tear breakup time, Schirmer 1 test, corneal sensitivity, and corneal topography.

RESULTS

Superficial punctate keratopathy (SPK) was observed at the interpalpebral area in 23 (64%) of 36 eyes. Corneal opacity was observed in three eyes (8.3%). Tear breakup time was below the lower limit of the normal range in all examined eyes, and the value of Schirmer 1 test was above the lower limit of the normal range in most of the examined eyes.

CONCLUSIONS

Superficial punctate keratopathy is observed in most cases of CIPA, which might predispose patients to corneal infection. Investigation of dry eye in patients with CIPA will provide unique opportunities to explore the critical roles of the autonomic sympathetic nervous system as well as the sensory nervous system in the physiology of tear production.

Three cousins with chronic foot ulcers from late-onset hereditary sensory and autonomic neuropathies type 2 (HSAN2)

The hereditary sensory and autonomic neuropathies (HSAN) are a group of rare disorders characterized by prominent sensory and autonomic neuropathy without motor involvement. We report three male cousins with chronic foot ulcers, all were affected with late-onset HSAN type 2 (HSAN2). In view of the history of consanguinity and male sex, X-linked recessive transmission was likely in our patients. According to the authors' knowledge this is the first report of HSAN2 from Iran.

Autosomal dominant hereditary sensory neuropathy with chronic cough and gastro-oesophageal reflux: clinical features in two families linked to chromosome 3p22-p24

Autosomal dominant hereditary sensory neuropathy (HSN I) is a clinically and genetically heterogeneous group of disorders, and in some families it is due to mutations in the serine palmitoyltransferase (SPTLC1) gene. We have characterized two families with HSN I associated with cough and gastro-oesophageal reflux (GOR). From a large Australian family, 27 individuals and from a smaller family, 11 individuals provided clinical information and blood for genetic analysis. Affected individuals had an adult onset of paroxysmal cough, GOR and distal sensory loss. Cough could be triggered by noxious odours or by pressure in the external auditory canal (Arnold's ear-cough reflex). Other features included throat clearing, hoarse voice, cough syncope and sensorineural hearing loss. Neurophysiological and pathological studies demonstrated a sensory axonal neuropathy. Gastric emptying studies were normal, and autonomic function and sweat tests were either normal or showed distal hypohidrosis. Cough was likely to be due to a combination of denervation hypersensitivity of the upper airways and oesophagus, and prominent GOR. Most affected individuals were shown on 24 h ambulatory oesophageal pH monitoring to have multiple episodes of GOR, closely temporally associated with coughing. Hoarse voice was probably attributable to acid-induced laryngeal damage, and there was no evidence of vocal cord palsy. No other cause for cough was found on most respiratory or otorhinological studies. Linkage to chromosome 3p22-p24 has been found in both families, with no evidence of linkage to loci for known HSN I, autosomal dominant hereditary motor and sensory neuropathy, hereditary GOR or triple A syndrome. These families represent a genetically novel variant of HSN I, with a distinctive cough owing to involvement of the upper aerodigestive tract.

Autosomal recessive spastic paraplegia (SPG30) with mild ataxia and sensory neuropathy maps to chromosome 2q37.3

The hereditary spastic paraplegias (HSPs) are a clinically and genetically heterogeneous group of neurodegenerative diseases characterized by progressive spasticity in the lower limbs. Twenty-nine different loci (SPG) have been mapped so far, and 11 responsible genes have been identified. Clinically, one distinguishes between pure and complex HSP forms which are variably associated with numerous combinations of neurological and extra-neurological signs. Less is known about autosomal recessive forms (ARHSP) since the mapped loci have been identified often in single families and account for only a small percentage of patients. We report a new ARHSP locus (SPG30) on chromosome 2q37.3 in a consanguineous family with seven unaffected and four affected members of Algerian origin living in Eastern France with a significant multipoint lod score of 3.8. Ten other families from France (n = 4), Tunisia (n = 2), Algeria (n = 3) and the Czech Republic (n = 1) were not linked to the newly identified locus thus demonstrating further genetic heterogeneity. The phenotype of the linked family consists of spastic paraparesis and peripheral neuropathy associated with slight cerebellar signs confirmed by cerebellar atrophy on one CT scan.

Calcaneal ulcer in a child with congenital insensitivity to pain syndrome

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare hereditary sensory neuropathy, comprising congenital insensitivity to pain, anhidrosis, and mental retardation. We present a 4-year-old child with CIPA and a calcaneal ulcer who was treated with double opposing rotation flaps, which eventually healed.

A new form of congenital proprioceptive sensory neuropathy associated with arthrogryposis multiplex

We report two siblings who presented with non-progressive marked sensory ataxia associated with arthrogryposis multiplex congenita (AMC). Deep tendon reflexes and H reflex were completely absent, but F waves were preserved. The sensory nerve conduction studies indicated the presence of relatively mild sensory polyneuropathy. The conventional somatosensory evoked potentials (SEPs) showed mildly prolonged latency for both the peripheral and cortical responses, suggesting a slowed conduction through the peripheral as well as central pathway. However, the 'proprioceptive SEPs' were absent, in conformity with complete loss of joint sense. Sural nerve biopsy revealed only mild thinning of myelin in the younger sister but was entirely normal in her brother. Taken together with the characteristic electrophysiological findings, the symptoms were considered to be due to predominant involvement of a selective population of somatosensory ganglions. The present cases showed no progression of the neurological deficit what-so-ever since birth, which strongly suggests a developmental anomaly or aplasia of a limited population of peripheral sensory neurons.

Inflammatory glial activation in the brain of a patient with hereditary sensory neuropathy type 1 with deafness and dementia

The brain of a patient with hereditary sensory neuropathy type 1 (HSN-1) associated with sensorineural deafness and early-onset dementia was neuropathologically investigated. Widespread neuronal degeneration in cerebral neocortex, hippocampus and basal ganglia was revealed, accounting for the clinical features. Loss of neurons with ballooning of residual neurons was remarkable in the hippocampus and frontal, parietal, and occipital lobes. Neuronal degeneration in these regions was accompanied by axonal dystrophy and glial reactions such as microgliosis and astrocytosis, however, only glial responses were prominent in the basal ganglia, brain-stem and cerebellum with mild neuronal loss. These results indicate that the widespread neuronal degeneration may be accelerated by inflammatory processes including glial activation in the brain of a patient with HSN-1 associated with deafness and dementia.

Desflurane used in a patient with congenital insensitivity to pain with anhidrosis during septic shock

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autonomic recessive disorder characterized by congenital analgesia, absence of sweating and mental retardation. Because of these abnormalities, the anesthetic managements in patients with CIPA deserve special attention. Here we report a 22-year-old man with CIPA receiving left above-knee amputation due to severe lower extremity infection. General anesthesia was maintained with desflurane, an intervention that has never been reported, and the whole course of operation was uneventful. This is also the first reported case of CIPA in Taiwan.

Intrasinus wood foreign body causing orbital cellulitis in congenital insensitivity to pain with anhidrosis syndrome

A 2-year-old boy with congenital insensitivity to pain with anhidrosis (CIPA) was referred with a 2-day history of left periorbital swelling and mucoid conjunctival discharge. Marked worsening was noted despite intramuscular ceftriaxone treatment for 3 days, with marked proptosis, conjunctival chemosis, and a frozen eye. Orbital cellulitis was suspected. Ceftriaxone was intravenously administered. Orbital computed tomography (CT) disclosed an inflammatory process in the medial aspect of the left orbit with ethmoiditis. Improvement was not noted after external ethmoidectomy and drainage of the intraconal abscess. Repeat CT showed a recurrent intraconal abscess. A revision external ethmoidectomy was performed, and a bent wooden match was removed from the posterior aspect of the ethmoidal sinus, after which significant clinical improvement was noted. In patients with CIPA, accidental or self-penetrated foreign bodies must be kept in mind when treating all types of wounds.

Hereditary sensory neuropathy with spastic paraplegia

We report the case of a 4-year-old boy with hereditary sensory neuropathy manifesting as insensitivity to pain in all four limbs and associated with spastic paraplegia. The patient was referred with multiple injuries to his fingers suggestive of self-mutilation and attributed to psychiatric disturbance. Clinical examination corrected the diagnosis by revealing insensitivity to pain in all four limbs, associated with spastic paraplegia. The histamine test reaction was positive, nerve biopsy and electrophysiological investigations confirmed sensory nerve involvement and the diagnosis of hereditary sensory neuropathy. Classification and treatment of such rare diseases is difficult and a multidisciplinary approach is often necessary.

Neurotrophic factors and their receptors in human sensory neuropathies

Neurotrophic factors may play key roles in pathophysiological mechanisms of human neuropathies. Nerve growth factor (NGF) is trophic to small-diameter sensory fibers and regulates nociception. This review focuses on sensory dysfunction and the potential of neurotrophic treatments. Genetic neuropathy. Mutations of the NGF high-affinity receptor tyrosine kinase A (Trk A) have been found in congenital insensitivity to pain and anhidrosis; these are likely to be partial loss-of-function mutations, as axon-reflex vasodilatation and sweating can be elicited albeit reduced, suggesting rhNGF could restore nociception in some patients. Leprous neuropathy. Decreased NGF in leprosy skin may explain cutaneous hypoalgesia even with inflammation and rhNGF may restore sensation, as spared nerve fibers show Trk A-staining. Diabetic neuropathy. NGF is depleted in early human diabetic neuropathy skin, in correlation with dysfunction of nociceptor fibers. We proposed rhNGF prophylaxis may prevent diabetic foot ulceration. Clinical trials have been disappointed, probably related to difficulty delivering adequate doses and need for multiple trophic factors. NGF and glial cell line-derived neurotrophic factor (GDNF) are both produced by basal keratinocytes and neurotrophin (NT-3) by suprabasal keratinocytes: relative mRNA expression was significantly lower in early diabetic neuropathy skin compared to controls, for NGF (P < 0.02), BDNF (P < 0.05), NT-3 (P < 0.05), GDNF (< 0.02), but not NT4/5, Trk A or p75 neurotrophin receptor (all P > 0.05). Posttranslational modifications of mature and pro-NGF may also affect bioactivity and immunoreactivity. A 53 kD band that could correspond to a prepro-NGF-like molecule was reduced in diabetic skin. Traumatic neuropathy and pain. While NGF levels are acutely reduced in injured nerve trunks, neuropathic patients with chronic skin hyperalgesia and allodynia show marked local increases of NGF levels; here anti-NGF agents may provide analgesia. Physiological combinations of NGF, NT-3 and GDNF, to mimic a 'surrogate target organ', may provide a novel 'homeostatic' approach to prevent the development and ameliorate intractable neuropathic pain (e.g., at painful amputation stumps).

A locus for hereditary sensory neuropathy with cough and gastroesophageal reflux on chromosome 3p22-p24

Hereditary sensory neuropathy type I (HSN I) is a group of dominantly inherited degenerative disorders of peripheral nerve in which sensory features are more prominent than motor involvement. We have described a new form of HSN I that is associated with cough and gastroesophageal reflux. To map the chromosomal location of the gene causing the disorder, a 10-cM genome screen was undertaken in a large Australian family. Two-point analysis showed linkage to chromosome 3p22-p24 (Zmax=3.51 at recombination fraction (theta) 0.0 for marker D3S2338). A second family with a similar phenotype shares a different disease haplotype but segregates at the same locus. Extended haplotype analysis has refined the region to a 3.42-cM interval, flanked by markers D3S2336 and D3S1266.

Autosomal dominant inherited neuropathies with prominent sensory loss and mutilations: a review

Hereditary sensory neuropathies (HSNs) are rare disorders characterized by progressive distal sensory loss, predominantly affecting the lower limbs. Foot ulcers, severe skin and bone infections, arthropathy, and amputations are frequent and feared complications. Occasionally, patients complain of spontaneous shooting or lancinating pain. Autonomic fibers can be affected to a variable degree. Patients with HSN can also have severe distal weakness, and some HSN variants have therefore been classified among the hereditary motor and sensory neuropathies (HMSNs). Molecular genetic studies of autosomal dominant inherited neuropathies with prominent sensory loss and ulceromutilating features have assigned the genetic loci for HMSN type 2B (Charcot-Marie-Tooth syndrome type 2B) and HSN type 1 to chromosomes 3q13-22 and 9q22.1-22.3, respectively. However, some families with HSN have been excluded for linkage to these loci, suggesting further genetic heterogeneity. Recently, disease-causing mutations in the SPTLC1 gene have been identified in patients with HSN type 1. In this review, we discuss the hallmark features associated with the distinct genetic subtypes of autosomal dominant inherited HSN and provide genotype-phenotype correlations.

Orofacial manifestations of congenital insensitivity to pain with anhidrosis: a report of 24 cases

PURPOSE

To report the incidence and severity of the oral and dental manifestations associated with congenital insensitivity to pain with anhidrosis (CIPA).

METHODS

Young children with CIPA underwent orofacial examination. The tongue, lips, and buccal mucosa were examined for soft tissue disorder. Missing and luxated teeth were recorded.

RESULTS

Twenty four patients (14 males and 10 females, mean age 60 months, range 9-144 months) with CIPA showed moderate to severe self-mutilation. Oral self-mutilation, such as biting injuries and scarring of soft tissues (tongue, lip, and buccal mucosa) were found in all patients. Fingertip biting was also found in most patients. Among infant patients, the mutilation was typically characterized by decubital ulcers of the tongue. Many edentulous areas due to previously extracted teeth were also found.

CONCLUSIONS

Early diagnosis and specific dental care for patients with CIPA can be helpful in prevention of the fingertip biting and orofacial manifestations seen in this disorder.

[Difficulty in the management of congenital insensitivity to pain]

We report a case of hereditary sensitive neuropathy associated with insensitivity to pain in an infant.

CASE REPORT

The girl was born after a normal full term pregnancy. She was hospitalized in the neonatal period because of hypotonia and recurrent cyanotic episodes due to false passage. The diagnosis of insensitivity to pain was suspected at nine months of age, as parallel with dentition, multiple mutilations of the tongue and the fingers were observed. The diagnosis was confirmed by biopsy taken from the sural nerve which showed a rarefaction of small myelinated fibres whereas unmyelinated fibres remained unaltered. At the age of six years, the general condition was good and the neurologic developement was satisfactory, neurotrophic and urologic complications currently being the main problem.

CONCLUSION

A multidisciplinary and specialized care associated with parental compliance was necessary to minimize the complications of this potentially severe disorder.

Congenital insensitivity to pain (hereditary sensory and autonomic neuropathy) HSAN: a report of two cases

Pain is one of the protective phenomenon possessed by the body. Pain arouses and demands our immediate attention. There are instances in which there is a congenital insensitivity to pain. Two cases of congenital insensitivity to pain are reported.

Ankle arthrodesis and tibial lengthening for congenital sensory neuropathy with anhidrosis

This report describes a patient with congenital sensory neuropathy with anhidrosis (CSNA) with destructive arthropathy of the left ankle joint that was treated with ankle arthrodesis and tibial lengthening, using an Ilizarov external fixator. The fusion at the ankle joint was successful, but, at the lengthening site, loosening of the apparatus occurred and formation and maturation of the distracted callus were delayed. Intramedullary nailing was used after the removal of the external fixator, and a low-intensity ultrasound device was employed, after which the distracted callus matured gradually. During the maturation period, the patient's dysplastic right hip joint was destroyed, without the occurrence of any severe symptoms. Distraction osteogenesis in patients with CSNA may lead to good results if rigid fixation, nonweight-bearing (i.e., adequate rest), and appropriate biological stimulation can be employed.

Indolent corneal ulcers in a patient with congenital insensitivity to pain with anhidrosis: a case report and literature review

PURPOSE

To report a case of bilateral corneal neurotrophic ulcer in patient with congenital insensitivity to pain with anhidrosis (CIPA) and review the literature.

CASE REPORT

A 6 year-old boy presented with bilateral central corneal sterile ulcer, decreased corneal sensitivity, moderately altered corneal reflex and normal tearing response. History taken, systemic evaluation and medical chart review were undertaken.

DISCUSSION

Fifty-two cases of CIPA have been reported worldwide. Fourteen cases had corneal involvement. The clinical picture of our patient is characteristic of CIPA.

CONCLUSIONS

Congenital insensitivity to pain with anhidrosis may present as neurotrophic corneal ulcer. We report herewith, this vision threatening corneal congenital abnormality. Early diagnosis and prompt treatment are mandatory to prevent corneal complications such as scarring and perforation.

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.