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.).

Autism spectrum disorder in a boy with congenital insensitivity to pain with anhidrosis: a case report.

BACKGROUND: In this case report, we described the past history, clinical manifestations, genetic characteristics and cognitive evaluation of a boy with congenital insensitivity to pain with anhidrosis (CIPA) who developed autism spectrum disorder (ASD). CASE PRESENTATION: The boy had an early onset of CIPA at the age of 48 months, and was later diagnosed with ASD at 5 years old. Developmental delays in communication, social skills and the presence of maladaptive behaviors were observed in the patient. Professional treatments significantly improved the developmental delays. CONCLUSIONS: This case demonstrated that ASD may develop in children with CIPA, and pediatricians should be aware that if they suspect or identify a child with CIPA that they should also be screened for ASD using similar examination and diagnostic tools as shown in the present report. Moreover, therapeutic interventions for ASD was helpful for the remission of both diseases.

A case report: Anesthetic management for open-heart surgery in a child with congenital insensitivity to pain with anhidrosis.

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare disease also known as hereditary sensory and autonomic neuropathy. CIPA is characterized by a lack of pain sensitivity and impaired development of sweat glands. Surgery is required for patients with self-mutilation and skeletal developmental disorders. Due to the disease's rarity and intricacy, anesthesia poses its challenges. Although there have been a few cases of CIPA patients receiving surgery and anesthesia, the number is very limited. Here, we report a case of a child with CIPA who underwent open-heart surgery and discuss the anesthetic considerations. We conclude that patients with CIPA undergoing open-heart surgery require some opioids, that muscle relaxants and volatile anesthetics should be used with extreme caution, and that airway management and temperature control require special attention.

Clinical, neuroimaging, and molecular spectrum of TECPR2-associated hereditary sensory and autonomic neuropathy with intellectual disability.

Bi-allelic TECPR2 variants have been associated with a complex syndrome with features of both a neurodevelopmental and neurodegenerative disorder. Here, we provide a comprehensive clinical description and variant interpretation framework for this genetic locus. Through international collaboration, we identified 17 individuals from 15 families with bi-allelic TECPR2-variants. We systemically reviewed clinical and molecular data from this cohort and 11 cases previously reported. Phenotypes were standardized using Human Phenotype Ontology terms. A cross-sectional analysis revealed global developmental delay/intellectual disability, muscular hypotonia, ataxia, hyporeflexia, respiratory infections, and central/nocturnal hypopnea as core manifestations. A review of brain magnetic resonance imaging scans demonstrated a thin corpus callosum in 52%. We evaluated 17 distinct variants. Missense variants in TECPR2 are predominantly located in the N- and C-terminal regions containing ß-propeller repeats. Despite constituting nearly half of disease-associated TECPR2 variants, classifying missense variants as (likely) pathogenic according to ACMG criteria remains challenging. We estimate a pathogenic variant carrier frequency of 1/1221 in the general and 1/155 in the Jewish Ashkenazi populations. Based on clinical, neuroimaging, and genetic data, we provide recommendations for variant reporting, clinical assessment, and surveillance/treatment of individuals with TECPR2-associated disorder. This sets the stage for future prospective natural history studies.

A Case of Congenital Insensitivity to Pain With Anhidrosis Comorbid With Attention Deficit Hyperactivity Disorder: Clinical Implications for Pathophysiology and Treatment.

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive genetic disorder caused by a mutation in the neurotrophic tyrosine kinase receptor (NTRK1) gene. CIPA is accompanied by abnormal catecholamine metabolism and decreased blood concentration of dopamine and norepinephrine. Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder of heterogeneous etiology and presentation, and recent reports have suggested a pathophysiological role of neurotrophins in ADHD. Furthermore, dopamine and norepinephrine are known to play major roles in the pathophysiology of ADHD, and the imbalance of monoaminergic and cholinergic systems as an underlying cause of ADHD has recently been studied. Here, we report the case of an 11-year-old boy with CIPA and comorbid ADHD. Our observations have important clinical implications for patients with CIPA. Because of deficiencies in self-control, proper management of these patients necessitates a highly structured and monitored environment, made dually important by possible comorbidity of ADHD.

Posterior column ataxia with retinitis pigmentosa coexisting with sensory-autonomic neuropathy and leukemia due to the homozygous p.Pro221Ser FLVCR1 mutation.

FLVCR1 encodes for a ubiquitous heme exporter, whose recessive mutations cause posterior column ataxia with retinitis pigmentosa (PCARP). Recently, FLVCR1 recessive mutations were also found in two sporadic children with hereditary sensory-autonomic neuropathy (HSAN). We report the unique case of a 33-year-old Italian woman with a combination of typical PCARP, sensory-autonomic neuropathy with sensory loss to all modalities and multiple autonomic dysfuctions, and acute lymphocytic leukemia. Molecular analysis demonstrated homozygosity for the previously identified FLVCR1 p.Pro221Ser variation. The same variation, in combination with a frameshift mutation, was previously identified in an Italian child with HSAN. Functional studies carried out on patient-derived lymphoblastoid cell lines showed decreased FLVCR1a transcript, increased reactive oxygen species, excessive intracellular heme accumulation, and increased number of Annexin V positive cells. This indicates that the homozygous p.Pro221Ser FLVCR1 variation compromises the ability of FLVCR1a to export heme leading to enhanced susceptibility to programmed cell death. Our study demonstrates the existence of a phenotypic continuum among the discrete disorders previously linked to FLVCR1 mutations, and suggests that the related alteration of heme metabolism may lead to the degeneration of specific neuronal cell populations.

Arthropathy-related pain in a patient with congenital impairment of pain sensation due to hereditary sensory and autonomic neuropathy type II with a rare mutation in the WNK1/HSN2 gene: a case report.

BACKGROUND: Hereditary sensory and autonomic neuropathy (HSAN) type II with WNK1/HSN2 gene mutation is a rare disease characterized by early-onset demyelination sensory loss and skin ulceration. To the best of our knowledge, no cases of an autonomic disorder have been reported clearly in a patient with WNK/HSN2 gene mutation and only one case of a Japanese patient with the WNK/HSN2 gene mutation of HSAN type II was previously reported. CASE PRESENTATION: Here we describe a 54-year-old woman who had an early childhood onset of insensitivity to pain; superficial, vibration, and proprioception sensation disturbances; and several symptoms of autonomic failure (e.g., orthostatic hypotension, fluctuation in body temperature, and lack of urge to defecate). Genetic analyses revealed compound homozygous mutations in the WNK1/HSN2 gene (c.3237_3238insT; p.Asp1080fsX1). The patient demonstrated sensory loss in the "stocking and glove distribution" but could perceive visceral pain, such as menstrual or gastroenteritis pain. She experienced frequent fainting episodes. She had undergone exenteration of the left metatarsal because of metatarsal osteomyelitis at 18 years. Sural nerve biopsy revealed a severe loss of myelinated and unmyelinated nerves. She complained of severe pain in multiple joints, even on having pain impairment. Although non-steroidal anti-inflammatory drugs are generally more effective than acetaminophen for arthritis, in our case, they were ineffective and acetaminophen (2400 mg/day) adequately controlled her pain and improved quality of life. Over 3 months, the numerical rating scale, pain interference scale of the Brief Pain Inventory, and the Pain Catastrophizing Scale decreased from 6/10 to 3/10, from 52/70 to 20/70, and from 22/52 to 3/52 points, respectively. CONCLUSIONS: This is the second reported case of a Japanese patient with WNK/HSN2 gene mutation of HSAN type II and the first reported case of an autonomic disorder in a patient with the WNK/HSN2 gene mutation. Acetaminophen adequately controlled arthropathy related pain in a patient with congenital impairment of pain sensation.

A novel DNMT1 mutation associated with early onset hereditary sensory and autonomic neuropathy, cataplexy, cerebellar atrophy, scleroderma, endocrinopathy, and common variable immune deficiency.

DNA methyltransferase 1 (DNMT1) is an enzyme which has a role in methylation of DNA, gene regulation, and chromatin stability. Missense mutations in the DNMT1 gene have been previously associated with two neurological syndromes: hereditary sensory and autonomic neuropathy type 1 with dementia and deafness (HSAN1E) and autosomal dominant cerebellar ataxia, deafness, and narcolepsy (ADCA-DN). We report a case showing overlap of both of these syndromes plus associated clinical features of common variable immune deficiency, scleroderma, and endocrinopathy that could also be mutation associated. Our patient was found to be heterozygous for a previously unreported frameshift mutation, c.1635_1637delCAA p.(Asn545del) in the DNMT1 gene exon 20. This case displays both the first frameshift mutation described in the literature which is associated with a phenotype with a high degree of overlap between HSAN1E and ADCA-DN and early age of onset (c. 8 years). Our case is also of interest as the patient displays a number of new non-neurological features, which could also be DNMT1 mutation related.

Sensory neuropathy with bone destruction due to a mutation in the membrane-shaping atlastin GTPase 3.

Many neurodegenerative disorders present with sensory loss. In the group of hereditary sensory and autonomic neuropathies loss of nociception is one of the disease hallmarks. To determine underlying factors of sensory neurodegeneration we performed whole-exome sequencing in affected individuals with the disorder. In a family with sensory neuropathy with loss of pain perception and destruction of the pedal skeleton we report a missense mutation in a highly conserved amino acid residue of atlastin GTPase 3 (ATL3), an endoplasmic reticulum-shaping GTPase. The same mutation (p.Tyr192Cys) was identified in a second family with similar clinical outcome by screening a large cohort of 115 patients with hereditary sensory and autonomic neuropathies. Both families show an autosomal dominant pattern of inheritance and the mutation segregates with complete penetrance. ATL3 is a paralogue of ATL1, a membrane curvature-generating molecule that is involved in spastic paraplegia and hereditary sensory neuropathy. ATL3 proteins are enriched in three-way junctions, branch points of the endoplasmic reticulum that connect membranous tubules to a continuous network. Mutant ATL3 p.Tyr192Cys fails to localize to branch points, but instead disrupts the structure of the tubular endoplasmic reticulum, suggesting that the mutation exerts a dominant-negative effect. Identification of ATL3 as novel disease-associated gene exemplifies that long-term sensory neuronal maintenance critically depends on the structural organisation of the endoplasmic reticulum. It emphasizes that alterations in membrane shaping-proteins are one of the major emerging pathways in axonal degeneration and suggests that this group of molecules should be considered in neuroprotective strategies.

Use of robotic-assisted laparoscopic Mitrofanoff appendicovesicostomy in a paediatric patient: problem encountered.

This report is of robotic-assisted laparoscopic Mitrofanoff appendicovesicostomy in a 12-year-old patient with detrusor underactivity and hereditary sensory neuropathy. The whole operation was performed in 555 minutes with no open conversion. The patient experienced one episode of stomal stenosis, which required dilatation. At 3-year follow-up, the patient had both stomal and urinary continence. This is a safe and effective procedure to create a means of urinary catheterisation with avoidance of a large unsightly scar and comparable clinical outcome to an open procedure.

Skeletal complications in congenital insensitivity to pain with anhidrosis: a case series of 14 patients and review of articles published in Japanese.

BACKGROUND: Congenital insensitivity to pain with anhidrosis (CIPA) is a rare disorder with various skeletal complications; thus, a compilation of data on affected patients could provide a valuable resource for the management of this disease. The aim of this study was to ascertain and report the frequency, location, age of onset, cause, and management of skeletal complications in Japanese patients with CIPA. METHODS: The medical records of 14 CIPA patients in our institute and information on 77 patients reported in Japanese articles were analyzed. Data regarding skeletal-system complications, including location, symptom, major cause and management of fractures, joint dislocations, infections, and Charcot joints, were extracted. RESULTS: Fractures occurred in 59/91 patients (65%), 91% of them in the lower limbs. Joint dislocations occurred in 27/91 patients (30%), 91% of them in the hip joint. Bone and joint infections occurred in 22 patients (24%) and Charcot joints in 26 patients (29%); 62% of infections and 87% of Charcot joints developed in the lower limbs. Most fractures occurred from 1 to 7 years of age; there was no apparent relationship between age and other complications. The major known causes of bone disorders were minor trauma such as short falls; however, most were of unknown cause. Conservative therapy was used more frequently than surgery to manage fractures, dislocations, and Charcot joints. CONCLUSIONS: These data show that most CIPA patients have skeletal complications, most of which occur in the lower limbs. Fractures are frequent between 1 and 7 years of age, whereas other bone disorders have no apparent age relationship. The major known causes of bone disorders were minor trauma such as short falls. Conservative therapy was more frequently used to manage fractures, dislocations, and Charcot joints.

Pediatric neuropathic arthropathy initially masquerading as inflammatory arthritis.

We describe a case of neuropathic arthropathy in the knees of a child eventually diagnosed with a hereditary sensory and autonomic neuropathy. The child was initially treated for rheumatologic disease at an outside institution. History and neurological workup revealed a neuropathy most consistent with hereditary sensory and autonomic neuropathy type II. Hereditary sensory and autonomic neuropathy should be considered in the differential diagnosis of children with joint abnormalities whose workup for an inflammatory arthropathy is negative and who exhibit diminished pain sensation on examination.

A rare case of congenital insensitivity to pain with anhidrosis.

A 22-month-old girl of consanguineous parents was admitted with a high-grade fever. She was found to have insensitivity to painful stimuli and an absence of perspiration. She also displayed self-mutilating behaviour and was insensitive to cold/hot water on her body. On examination, there was loss of the tip of the tongue, missing teeth, generalised xerosis, and several ulcers at sites of minor trauma. She also had dysplastic nails and digital ulcers. Sensory examination demonstrated a complete lack of awareness of pain and temperature, vibration and fine touch were intact and lacrimation was normal. Differential diagnoses of hereditary sensory and autonomic neuropathy (HSAN), Lesch-Nyhan syndrome, hypohidrotic ectodermal dysplasia and leprosy were considered. Results of routine blood investigations including serum uric acid were normal. On performing clinical exome sequencing, the diagnosis of congenital insensitivity to pain with anhidrosis (CIPA) of autosomal recessive inheritance was confirmed. A novel, predicted to be pathogenic variant detected at exon 16 of the NTRK1 gene resulting in congenital insensitivity to pain with anhidrosis is reported.Abbreviations: CIPA: congenital Insensitivity to pain with anhidrosis; HSAN: hereditary sensory and autonomic neuropathy; NGF: nerve growth factor; NTRK1: neurotrophic tyrosine kinase receptor 1 gene; TrKA: tropomyosin receptor kinase A.

Congenital insensitivity to pain with anhidrosis presenting with palmoplantar keratoderma.

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal-recessive disease caused by mutations in the NTRK1 gene. The disease is characterized by insensitivity to pain and absence of thermal perception. Herein a 6-year-old boy is presented with a large ulcer on the sole of his right foot and a thick, hyperkeratotic appearance of his palms and soles; there was also a medical history of hyperthermia, anhidrosis, recurrent bone fractures, osteomyelitis, injuries, mental retardation, dry and exfoliative skin, insensitivity to pain, and lack of thermal sensation. Genetic studies revealed a homozygote mutation in the NTRK1 gene. Although the patient initially presented with palmoplantar keratoderma, genetic studies confirmed the diagnosis of CIPA.

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.