Severe neuromuscular forms of glycogen storage disease type IV: Histological, clinical, biochemical, and molecular findings in a large French case series.

Glycogen storage disease type IV (GSD IV), also called Andersen disease, or amylopectinosis, is a highly heterogeneous autosomal recessive disorder caused by a glycogen branching enzyme (GBE, 1,4-alpha-glucan branching enzyme) deficiency secondary to pathogenic variants on GBE1 gene. The incidence is evaluated to 1:600 000 to 1:800 000 of live births. GBE deficiency leads to an excessive deposition of structurally abnormal, amylopectin-like glycogen in affected tissues (liver, skeletal muscle, heart, nervous system, etc.). Diagnosis is often guided by histological findings and confirmed by GBE activity deficiency and molecular studies. Severe neuromuscular forms of GSD IV are very rare and of disastrous prognosis. Identification and characterization of these forms are important for genetic counseling for further pregnancies. Here we describe clinical, histological, enzymatic, and molecular findings of 10 cases from 8 families, the largest case series reported so far, of severe neuromuscular forms of GSD IV along with a literature review. Main antenatal features are: fetal akinesia deformation sequence or arthrogryposis/joint contractures often associated with muscle atrophy, decreased fetal movement, cystic hygroma, and/or hydrops fetalis. If pregnancy is carried to term, the main clinical features observed at birth are severe hypotonia and/or muscle atrophy, with the need for mechanical ventilation, cardiomyopathy, retrognathism, and arthrogryposis. All our patients were stillborn or died within 1 month of life. In addition, we identified five novel GBE1 variants.

The emerging spectrum of fetal acetylcholine receptor antibody-related disorders (FARAD).

In utero exposure to maternal antibodies targeting the fetal acetylcholine receptor isoform (fAChR) can impair fetal movement, leading to arthrogryposis multiplex congenita (AMC). Fetal AChR antibodies have also been implicated in apparently rare, milder myopathic presentations termed fetal acetylcholine receptor inactivation syndrome (FARIS). The full spectrum associated with fAChR antibodies is still poorly understood. Moreover, since some mothers have no myasthenic symptoms, the condition is likely underreported, resulting in failure to implement effective preventive strategies. Here we report clinical and immunological data from a multicentre cohort (n = 46 cases) associated with maternal fAChR antibodies, including 29 novel and 17 previously reported with novel follow-up data. Remarkably, in 50% of mothers there was no previously established myasthenia gravis (MG) diagnosis. All mothers (n = 30) had AChR antibodies and, when tested, binding to fAChR was often much greater than that to the adult AChR isoform. Offspring death occurred in 11/46 (23.9%) cases, mainly antenatally due to termination of pregnancy prompted by severe AMC (7/46, 15.2%), or during early infancy, mainly from respiratory failure (4/46, 8.7%). Weakness, contractures, bulbar and respiratory involvement were prominent early in life, but improved gradually over time. Facial (25/34; 73.5%) and variable peripheral weakness (14/32; 43.8%), velopharyngeal insufficiency (18/24; 75%) and feeding difficulties (16/36; 44.4%) were the most common sequelae in long-term survivors. Other unexpected features included hearing loss (12/32; 37.5%), diaphragmatic paresis (5/35; 14.3%), CNS involvement (7/40; 17.5%) and pyloric stenosis (3/37; 8.1%). Oral salbutamol used empirically in 16/37 (43.2%) offspring resulted in symptom improvement in 13/16 (81.3%). Combining our series with all previously published cases, we identified 21/85 mothers treated with variable combinations of immunotherapies (corticosteroids/intravenous immunoglobulin/plasmapheresis) during pregnancy either for maternal MG symptom control (12/21 cases) or for fetal protection (9/21 cases). Compared to untreated pregnancies (64/85), maternal treatment resulted in a significant reduction in offspring deaths (P < 0.05) and other complications, with treatment approaches involving intravenous immunoglobulin/ plasmapheresis administered early in pregnancy most effective. We conclude that presentations due to in utero exposure to maternal (fetal) AChR antibodies are more common than currently recognized and may mimic a wide range of neuromuscular disorders. Considering the wide clinical spectrum and likely diversity of underlying mechanisms, we propose 'fetal acetylcholine receptor antibody-related disorders' (FARAD) as the most accurate term for these presentations. FARAD is vitally important to recognize, to institute appropriate management strategies for affected offspring and to improve outcomes in future pregnancies. Oral salbutamol is a symptomatic treatment option in survivors.

Expanding the phenotype of Bruck syndrome: Severe limb deformity, arthrogryposis, congenital cardiac disease and pulmonary hemorrhage.

Bruck syndrome is a rare collagen disorder with autosomal recessive inheritance caused by pathogenic variants in either FKBP10 or PLOD2 genes. It is characterized by bone fragility and fractures similar in severity and variability to osteogenesis-imperfecta as well as congenital joint contractures. This article describes an infant with a homozygous (partial) gene deletion of PLOD2 that includes the start codon and would be expected to lead to nonfunctional protein product. The infant had a severe phenotype of Bruck syndrome and is the only reported case of Bruck syndrome with congenital cardiac disease (triscuspid valve dysplasia with severe regurgitation, mitral valve prolapses with moderate regurgitation, and pulmonary hypertension) and pulmonary hemorrhage. We hypothesize that the additional feature of congenital cardiac disease in this case was due to the underlying defect in type I collagen, and that the pulmonary hemorrhage was multifactorial, with underlying vessel fragility, rib fractures, and high pulmonary pressures likely to be major contributing factors. Management was largely supportive with the use of bisphosphonates to assist in pain management. Care was complicated by comorbid cardiopulmonary compromise, limited evidence-base guiding care, and difficulties in discussing end-of-life care.

Ichthyosis, petechiae, and arthrogryposis in a neonate.

Gaucher disease is a rare lysosomal storage disorder caused by a deficiency in glucocerebrosidase. This enzyme deficiency leads to the accumulation of toxic metabolites in various organs. Multiple subtypes of this disease have been described; however, the perinatal-lethal form is extremely rare and challenging to diagnose. We present a case of a newborn girl with ichthyosis, petechiae, and arthrogryposis, later found to be homozygous for a pathogenic variant of the glucocerebrosidase gene. This case highlights the potential role of dermatologists in the recognition of this rare disease.

The Effectiveness of Serial Casting in the Treatment of Recurrent Equinovarus in Children With Arthrogryposis.

BACKGROUND: Arthrogryposis multiplex congenita (AMC) is characterized by joint contractures in 2 or more body areas, often resulting in clubfoot deformities that are typically stiffer than those seen in idiopathic clubfoot deformities. While surgery is routinely used to treat clubfoot in AMC, it has a high rate of recurrence and complications. Current literature suggests serial casting (SC) could be useful in treating clubfoot in AMC, though evidence of its effectiveness is limited. METHODS: Passive range of motion (PROM), dynamic foot pressure, parent-reported Pediatric Outcomes Data Collection Instrument, brace tolerance, and the need for post-casting surgery were evaluated retrospectively in children with AMC treated with SC to address clubfoot deformities. Analysis of variance or paired t tests were used as appropriate on pre-casting, short-term (within 6 mo after SC) and/or longer-term (6 to 18 mo after SC) parameters to determine the effectiveness of SC. Brace tolerance before and after SC was analyzed using the Global Test for Symmetry, and medical records were reviewed to determine the need for surgery post-SC. RESULTS: Forty-six children (6.1±3.1 y old) were cast an average of 2.5±1.9 times, resulting in 206 SC episodes. PROM showed improvement in ankle dorsiflexion and forefoot abduction in the short term (P<0.05), returning to baseline measurements in the long term (P=0.09). Brace tolerance improved after casting (P<0.05). Only 15% of feet required surgery at follow-up at 10.3±5.5 years. There were no significant changes in dynamic foot pressure or Pediatric Outcomes Data Collection Instrument results after SC, except for an increase in the pain subtest (P<0.05). CONCLUSIONS: Serial casting in children with AMC can be effective in temporarily improving PROM and improving brace tolerance, but it does not impact dynamic barefoot position. Positive impact of conservative management in children with AMC can potentially delay or reduce the need for invasive surgical intervention by improving PROM and brace tolerance. LEVEL OF EVIDENCE: Level III, Retrospective Comparative Study.

Fatal Retroperitoneal Bleeding in Neurofibromatosis Type 1: A Clinically Occult Complication.

ABSTRACT: Neurofibromatosis type 1 (NF1) is a common, autosomal dominant neurocutaneous syndrome. The most frequent clinical manifestations include multiple neurofibromas, café-au-lait spots, dystrophic scoliosis, benign and malignant peripheral nerve sheath tumors, and paragangliomas. Neurofibromatosis type 1 vasculopathy is a less well-recognized constellation of vascular pathologies that can cause significant medical complications in patients with NF1. A rare manifestation of this process is neurofibroma infiltration of vasculature with resultant bleeding. The case presented herein illustrates a rare example of a massive fatal hemorrhage due to disruption of a large paraspinal artery in the setting of a diffuse, infiltrative neurofibroma. This case highlights the potential of benign neurofibromas to infiltrate major blood vessels, leading to extensive bleeding and death.

Identification of UBA1 as the causative gene of an X-linked non-Kennedy spinal-bulbar muscular atrophy.

BACKGROUND AND PURPOSE: Spinal-bulbar muscular atrophy (SBMA) (Kennedy's disease) is a motor neuron disease. Kennedy's disease is nearly exclusively caused by mutations in the androgen receptor encoding gene (AR). The results of studies aimed at identification of the genetic cause of a disease that best approximates SBMA in a pedigree (four patients) without mutations in AR are reported. METHODS: Clinical investigations included thorough neurological and non-neurological examinations and testing. Genetic analysis was performed by exome sequencing using standard protocols. UBA1 mutations were modeled on the crystal structure of UBA1. RESULTS: The clinical features of the patients are described in detail. A missense mutation in UBA1 (c.T1499C; p.Ile500Thr) was identified as the probable cause of the non-Kennedy SBMA in the pedigree. Like AR, UBA1 is positioned on chromosome X. UBA1 is a highly conserved gene. It encodes ubiquitin-like modifier activating enzyme 1 (UBA1) which is the major E1 enzyme of the ubiquitin-proteasome system. Interestingly, UBA1 mutations can also cause infantile-onset X-linked spinal muscular atrophy (XL-SMA). The mutation identified here and the XL-SMA causative mutations were shown to affect amino acids positioned in the vicinity of UBA1's ATP binding site and to cause structural changes. CONCLUSION: UBA1 was identified as a novel SBMA causative gene. The gene affects protein homeostasis which is one of most important components of the pathology of neurodegeneration. The contribution of this same gene to the etiology of XL-SMA is discussed.

Bruck Syndrome: Beyond the Obvious.

INTRODUCTION: Bruck syndrome is a rare autosomal recessive disease characterized by multiple joint contractures, bone fragility, and fractures. Two genes have been associated with Bruck syndrome, FKBP10 and PLOD2, though they are phenotypically indistinguishable. CASE PRESENTATION: We present a prenatally diagnosed case of Bruck syndrome in a young multiparous woman, with no notable personal, family or obstetric history. A 12-week ultrasound raised the suspicion of short long bones, subsequently confirmed at 16 weeks. In addition, bilateral fixed flexion of the elbow, wrist, and knee joints as well as talipes was observed. Chromosomal SNP microarray analysis (0.2 Mb) detected a homozygous deletion at chromosome 3, band q24, involving a part of PLOD2 to a part of PLSCR4. At mid-trimester morphology, bilateral intrauterine fractures of the humerus and femur were evident. In the late third trimester, a fetal echocardiogram noted enlargement of the right heart with severe tricuspid regurgitation in combination with pulmonary insufficiency and a restrictive arterial duct. The potential risk of premature closure of the ductus arteriosus near term led to delivery by emergency caesarean section. CONCLUSION: To our knowledge, this is the first case of Bruck syndrome prenatally confirmed by chromosomal microarray analysis and the second reported case with an extra-skeletal abnormality. This case highlights the importance of comprehensive fetal morphological assessment during pregnancy as diagnosis of an additional abnormality has the potential to impact both management and prognosis.

Total joint replacement of the hip and knee in patients with arthrogryposis multiplex congenita: a report of six joints.

INTRODUCTION: Arthrogryposis multiplex congenita (AMC) is a rare congenital condition that leads to severe joint contractures and deformities. As painful joint dysplasia and degeneration might develop over time, total joint replacement (TJR) can be a potential treatment option for these patients. The aim of this study is to investigate functional results, implant survivorship and potential complications in patients with AMC who undergo hip or knee arthroplasty. MATERIALS AND METHODS: We retrospectively identified six TJR in three patients at a single centre performed between 2006 and 2019. The median patient age at surgery was 23 years and the median follow-up period was 69 (IQR 55-99) months. We analysed surgical technique, implant survivorship and complications as well as functional outcome determined by pain reported on the Numerical Rating Scale (NRS), patient-reported outcome scores [Oxford Hip Score (OHS), Harris Hip score (HHS), Oxford Knee Score (OKS)], range of motion and ambulatory status. Depending on data distribution means with ranges and median with interquartile range were compared with the Wilcoxon signed rank test or Student's t test. The level of significance was defined at < 0.05. RESULTS: In hips, the mean range of motion in flexion/extension (52° vs. 85°, p = 0.014) and in rotation (28° vs. 68°, p = 0.02) as well as mean pain score on the NRS (8.5 vs. 0, p = 0.001), OHS (9 vs. 26, p = 0.031) and HHS (17 vs. 52, p = 0.007) significantly improved. In knees, mean range of motion (55° vs. 93°, p = 0.403), mean pain score on the NRS (0 vs. 7) and the OKS (2 vs. 21) also improved. While the ambulatory status did not change, the patients who were wheelchair dependent reported less problems with transfers to a bed or chair and the patient who ambulated reported an improved walking distance. One total knee arthroplasty (TKA) underwent revision for an acute, late infection 155 months following the initial surgery. CONCLUSIONS: TJR is a safe procedure in patients with AMC that effectively improves function and reduces pain irrespective of preoperative ambulatory status.

The mystery of monozygotic twinning I: What can Amyoplasia tell us about monozygotic twinning and the possible role of twin-twin transfusion?

Amyoplasia is a very specific, nongenetic clinically recognizable form of arthrogryposis, representing about one-third of individuals with arthrogryposis surviving the newborn period. There is a markedly increased number of individuals with Amyoplasia who are one of monozygotic (MZ) twins, with the other twin being normal. Thus, it would appear that Amyoplasia is definitely associated with and may be caused by an MZ twinning event. The twin-twin transfusion seen in MZ twins could play an etiologic role in producing Amyoplasia. In this article, Amyoplasia twinning is compared to twinning in other forms of arthrogryposis. The accompanying paper examines various types of MZ twinning (Hall, 2021). Amyoplasia is primarily associated with spontaneous MZ twinning.

The mystery of monozygotic twinning II: What can monozygotic twinning tell us about Amyoplasia from a review of the various mechanisms and types of monozygotic twinning?

Monozygotic (MZ) twins ("identical twins") are essentially unique to human beings. Why and how they arise is not known. This article reviews the possible different types of MZ twinning recognized in the previous article on twins and arthrogryposis. There appear to be at least three subgroups of MZ twinning: spontaneous, familial, and those related to artificial reproductive technologies. Each is likely to have different etiologies and different secondary findings. Spontaneous MZ twinning may relate to "overripe ova." Amyoplasia, a specific nongenetic form of arthrogryposis, appears to occur in spontaneous MZ twinning and may be related to twin-twin transfusion.

Further delineation of MYO18B-related autosomal recessive Klippel-Feil syndrome with myopathy and facial dysmorphism.

Klippel-Feil syndrome 4 (KFS4; MIM# 616549) is an autosomal recessive disorder caused by biallelic pathogenic variants in MYO18B and comprises, in addition to Klippel-Feil anomaly (KFA), nemaline myopathy, facial dysmorphism, and short stature. We aim to outline the natural history of KFS4 and provide an updated description of its clinical, radiological, laboratory, and molecular findings. We comprehensively analyzed the medical records of 6 Saudi and 1 American patients (including 5 previously unpublished cases) with a molecularly confirmed diagnosis of KFS4. All patients had myopathy of varying severity that followed a slowly progressive or non-progressive course, affecting primarily the proximal musculature of the lower limb although hand involvement with distal arthrogryposis and abnormal interphalangeal creases was also observed. KFA and characteristic dysmorphic features, including ptosis and bulbous nose, were observed in all but two patients. The causal MYO18B variants were a founder NM_032608.5:c.6905C>A; p.(Ser2302*) variant in the Saudi patients (P1-P6) and a novel MYO18B homozygous variant (c.6660_6670del;p.[Arg2220Serfs*74]) in the American Caucasian patient (P7). We report the phenotypic and genetic findings in seven patients with KFS4. We describe the natural history of this disease, confirm myopathy as a universal feature and describe its pattern and progression, and note interesting differences between the phenotypes observed in patients with KFA and those without.

COFS type 3 in an Indian family with antenatally detected arthrogryposis.

Fetal akinesia and contractures can be caused by mutations in various genes that lead to overlapping phenotypes with contractures, rocker bottom feet, cerebellar hypoplasia, ventriculomegaly, growth retardation, pulmonary hypoplasia, cystic hygroma and cleft palate in various combinations. Cerebro-oculo-facio-skeletal (COFS) syndrome is a condition resulting from defects in DNA repair pathway, and genes involved include ERCC1 (COFS), ERCC2 (XPD), ERCC5(XPG), and ERCC6 (CSB). It is a severe disorder presenting in fetal or neonatal period with microcephaly, arthrogryposis, prominent nose, and kyphoscoliosis, and leads to early death in childhood. We report a baby with antenatally identified arthrogryposis in which the homozygous pathogenic variant in exon 8 was identified in ERCC5 gene, by targeted next generation sequencing. This was predicted to cause premature chain termination in the protein. ERCC5 gene is mainly implicated in xeroderma pigmentosum, sometimes in COFS syndrome.

The 5-Year Outcome of the Ponseti Method in Children With Idiopathic Clubfoot and Arthrogryposis.

BACKGROUND: The Ponseti method effectively treats idiopathic clubfoot, but its effectiveness in treating the stiffer clubfoot associated with arthrogryposis is less clear. The purpose of this study was to assess the comparative effectiveness of the Ponseti method in 5-year-old children with either idiopathic clubfoot or clubfoot due to arthrogryposis. METHODS: The outcomes of the Ponseti method were retrospectively evaluated in children with idiopathic clubfoot and clubfoot associated with arthrogryposis. The children with clubfoot were seen at our hospital between 2012 and 2019 and were 4.0 to 6.9 years old at the time of their evaluation. Outcomes of the 2 groups of children with clubfoot were assessed using passive range of motion, foot pressure analysis, the Gross Motor Function Measure Dimension-D, and parent report using the Pediatric Outcomes Data Collection Instrument. These results were also compared with the same measures from a group of typically developing children. Surgical and bracing history was also recorded. RESULTS: A total of 117 children were included (89 idiopathic clubfoot and 28 associated with arthrogryposis) with an average age of 4.8±0.8 years. The historical gait analyses of 72 typically developing children were used as a control, with an average age of 5.2±0.8 years. Significant residual equinovarus was seen in both children with idiopathic clubfoot and associated with arthrogryposis according to passive range of motion and foot pressure analysis when compared with normative data. Children with arthrogryposis demonstrated limited transfer and basic mobility, sports functioning, and global functioning while children with idiopathic clubfoot were significantly different from their typically developing peers in only transfer and basic mobility. CONCLUSIONS: Although children with idiopathic clubfoot continue with some level of residual deformity, the Ponseti method is effective in creating a pain-free, highly functional foot. In children with clubfoot associated with arthrogryposis, the Ponseti method is successful in creating a braceable foot that can delay the need for invasive surgical intervention. LEVEL OF EVIDENCE: Level III, Therapeutic Studies-Investigating the Results of Treatment.

Pain among children and adults living with arthrogryposis multiplex congenita: A scoping review.

Clinical interventions and research have mostly focused on the orthopedic and genetic outcomes of individuals with arthrogryposis multiplex congenita (AMC), and although pain has gained recognition as an important issue experienced by individuals with AMC, it has received little attention within the AMC literature. The aims of this scoping review were to describe the pain experiences of children and adults with AMC, to identify pain assessment tools and management techniques, and document the impact of pain on participation in everyday activities among children and adults with AMC. A search of the literature was conducted in four search engines and identified a total of 89 articles. Once study eligibility was reviewed, 21 studies met the selection criteria and were included in this review. Pain appears to be more commonly experienced in adults with AMC compared with children with AMC, with individuals having undergone multiple corrective procedures self-reporting pain more often. In adult populations, musculoskeletal chronic pain is a significant problem, resulting in restrictions in activities of daily living, mobility, and participation. Researchers and clinicians must agree on the use of validated measures appropriate for evaluating pain in AMC and the use of appropriate pain management techniques to relieve pain. Pediatric studies should focus on determining how commonly pain is experienced in infants, children, and adolescents with AMC. Pain in adults with AMC should be acknowledged to offer proper client-centered interventions throughout the lifespan.

Impaired Presynaptic High-Affinity Choline Transporter Causes a Congenital Myasthenic Syndrome with Episodic Apnea.

The neuromuscular junction (NMJ) is one of the best-studied cholinergic synapses. Inherited defects of peripheral neurotransmission result in congenital myasthenic syndromes (CMSs), a clinically and genetically heterogeneous group of rare diseases with fluctuating fatigable muscle weakness as the clinical hallmark. Whole-exome sequencing and Sanger sequencing in six unrelated families identified compound heterozygous and homozygous mutations in SLC5A7 encoding the presynaptic sodium-dependent high-affinity choline transporter 1 (CHT), which is known to be mutated in one dominant form of distal motor neuronopathy (DHMN7A). We identified 11 recessive mutations in SLC5A7 that were associated with a spectrum of severe muscle weakness ranging from a lethal antenatal form of arthrogryposis and severe hypotonia to a neonatal form of CMS with episodic apnea and a favorable prognosis when well managed at the clinical level. As expected given the critical role of CHT for multisystemic cholinergic neurotransmission, autonomic dysfunctions were reported in the antenatal form and cognitive impairment was noticed in half of the persons with the neonatal form. The missense mutations induced a near complete loss of function of CHT activity in cell models. At the human NMJ, a delay in synaptic maturation and an altered maintenance were observed in the antenatal and neonatal forms, respectively. Increased synaptic expression of butyrylcholinesterase was also observed, exposing the dysfunction of cholinergic metabolism when CHT is deficient in vivo. This work broadens the clinical spectrum of human diseases resulting from reduced CHT activity and highlights the complexity of cholinergic metabolism at the synapse.

Nemaline myopathy and distal arthrogryposis associated with an autosomal recessive TNNT3 splice variant.

A male neonate presented with severe weakness, hypotonia, contractures and congenital scoliosis. Skeletal muscle specimens showed marked atrophy and degeneration of fast fibers with striking nemaline rods and hypertrophy of slow fibers that were ultrastructurally normal. A neuromuscular gene panel identified a homozygous essential splice variant in TNNT3 (chr11:1956150G > A, NM_006757.3:c.681+1G > A). TNNT3 encodes skeletal troponin-Tfast and is associated with autosomal dominant distal arthrogryposis. TNNT3 has not previously been associated with nemaline myopathy (NM), a rare congenital myopathy linked to defects in proteins associated with thin filament structure and regulation. cDNA studies confirmed pathogenic consequences of the splice variant, eliciting exon-skipping and intron retention events leading to a frameshift. Western blot showed deficiency of troponin-Tfast protein with secondary loss of troponin-Ifast . We establish a homozygous splice variant in TNNT3 as the likely cause of severe congenital NM with distal arthrogryposis, characterized by specific involvement of Type-2 fibers and deficiency of troponin-Tfast .

Peripheral neuropathy in diabetes: it's not always what it looks like.

BACKGROUND: Hereditary Neuropathy with liability to Pressure Palsies (HNPP) is an autosomal dominant neuropathy, associated with deletion of the Peripheral Myelin Protein-22 (PMP-22) gene, causing recurrent painless palsies with age of onset between 10 and 30 years old. Only a few cases of Type 2 Diabetes and HNPP have been described and the coexistence of HNPP and Type 1 diabetes has never been reported. CASE REPORT: A 54-year old man with a history of Type 1 diabetes, managed with continuous subcutaneous insulin infusion (CSII), presented with deterioration of long-standing motor and sensory symptoms, previously attributed to golfer's elbow, diabetic neuropathy and spinal degenerative disease. He had multilevel severe spine degenerative changes and L4/L5 and L5/S1 root impingements with a L4/L5 discectomy performed when he was 25 years old. On physical examination he had normal power and distal hypoaesthesia of the digits and plantar aspect of the feet. Investigations revealed normal full blood count, liver and renal function, electrolytes, vitamin B12 and serum folate. He suffered from primary hypothyroidism and thyroid function tests indicated adequate levothyroxine replacement. Nerve conduction studies revealed a generalized demyelinating sensorimotor neuropathy, with more severe involvement of nerves over entrapment sites. Further history that his father suffered from episodes of weakness and numbness was elicited. Genetic analysis revealed one copy of the PMP22 gene at 17p11.2 confirming the diagnosis of HNPP. CONCLUSION: In people with diabetes the evaluation of peripheral neuropathy should include a careful history, a comprehensive physical examination, blood tests and in some cases nerve conduction studies and genetic testing.

TOR1A variants cause a severe arthrogryposis with developmental delay, strabismus and tremor.

See Ginevrino and Valente (doi:10.1093/brain/awx260) for a scientific commentary on this article. Autosomal dominant torsion dystonia-1 is a disease with incomplete penetrance most often caused by an in-frame GAG deletion (p.Glu303del) in the endoplasmic reticulum luminal protein torsinA encoded by TOR1A. We report an association of the homozygous dominant disease-causing TOR1A p.Glu303del mutation, and a novel homozygous missense variant (p.Gly318Ser) with a severe arthrogryposis phenotype with developmental delay, strabismus and tremor in three unrelated Iranian families. All parents who were carriers of the TOR1A variant showed no evidence of neurological symptoms or signs, indicating decreased penetrance similar to families with autosomal dominant torsion dystonia-1. The results from cell assays demonstrate that the p.Gly318Ser substitution causes a redistribution of torsinA from the endoplasmic reticulum to the nuclear envelope, similar to the hallmark of the p.Glu303del mutation. Our study highlights that TOR1A mutations should be considered in patients with severe arthrogryposis and further expands the phenotypic spectrum associated with TOR1A mutations.

Severe renal Fanconi and management strategies in Arthrogryposis-Renal dysfunction-Cholestasis syndrome: a case report.

BACKGROUND: Arthrogryposis-Renal dysfunction-Cholestasis syndrome (ARC, MIM#208085) is a rare multisystem disease due to mutations in the VPS33B and VIPAR genes, both involved in maintaining apical-basolateral cell polarity. The correlation between mutations and phenotype in the ARC Syndrome is not well described. We report on a 6 year old patient who presented with severe renal Fanconi as first manifestation of ARC related to a combined de novo mutation in the VPS33B gene. CASE PRESENTATION: A 6 year old girl presented during the first year of life with severe renal Fanconi as the first manifestation of ARC-Syndrome. This case presents all defining features of ARC syndrome (including liver, skin and articular manifestations) with predominantly renal impairment at presentation. This novel mutation may be associated with a pronounced renal phenotype in ARC. Furthermore, we report on the successful use of LDL-Apheresis and biliodigestive derivation for treatment of cholestatic pruritus with encouraging results. CONCLUSION: ARC is a heterogeneous disorder with early mortality. This case report contributes to a better understanding of this rare disorder, describes a novel mutation in the VPS33B gene and presents an innovative rescue treatment approach.