Consensus recommendations for diagnosis and treatment of Multiple Sclerosis: 2023 revision of the MENACTRIMS guidelines

With evolving diagnostic criteria and the advent of new oral and parenteral therapies for Multiple Sclerosis (MS), most current diagnostic and treatment algorithms need revision and updating. The diagnosis of MS relies on incorporating clinical and paraclinical findings to prove dissemination in space and time and exclude alternative diseases that can explain the findings at hand. The differential diagnostic workup should be guided by clinical and laboratory red flags to avoid unnecessary tests. Appropriate selection of MS therapies is critical to maximize patient benefit. The current guidelines review the current diagnostic criteria for MS and the scientific evidence supporting treatment of acute relapses, radiologically isolated syndrome, clinically isolated syndrome, relapsing remitting MS, progressive MS, pediatric cases and pregnant women. The purpose of these guidelines is to provide practical recommendations and algorithms for the diagnosis and treatment of MS based on current scientific evidence and clinical experience.

Nine Hereditary Movement Disorders First Described in Asia: Their History and Evolution

Clinical case studies and reporting are important to the discovery of new disorders and the advancement of medical sciences. Both clinicians and basic scientists play equally important roles leading to treatment discoveries for both cures and symptoms. In the field of movement disorders, exceptional observation of patients from clinicians is imperative, not just for phenomenology but also for the variable occurrences of these disorders, along with other signs and symptoms, throughout the day and the disease course. The Movement Disorders in Asia Task Force (TF) was formed to help enhance and promote collaboration and research on movement disorders within the region. As a start, the TF has reviewed the original studies of the movement disorders that were preliminarily described in the region. These include nine disorders that were first described in Asia: Segawa disease, PARK-Parkin, X-linked dystonia-parkinsonism, dentatorubral-pallidoluysian atrophy, Woodhouse-Sakati syndrome, benign adult familial myoclonic epilepsy, Kufor-Rakeb disease, tremulous dystonia associated with mutation of the calmodulin-binding transcription activator 2 gene, and paroxysmal kinesigenic dyskinesia. We hope that the information provided will honor the original researchers and help us learn and understand how earlier neurologists and basic scientists together discovered new disorders and made advances in the field, which impact us all to this day.

Expanding the genotype-phenotype landscape of PDE10A-associated movement disorders

BACKGROUND

Phosphodiesterase 10A (PDE10A) controls body movements by regulating cyclic adenosine monophosphate signaling in the basal ganglia. Two classes of PDE10A variants are reported with distinctive genotype-phenotype correlation. The autosomal recessive mutations in the GAF-A and catalytic domains are associated with compromised membrane localization, and manifest with infantile onset chorea, developmental, and cognition delay with normal brain MRI. Conversely, autosomal dominant mutations in the GAF-B domain cause protein aggregates which results in childhood onset chorea in the context of normal cognition and development, with striatal lesions.

METHODS

Phenotypic characteristics of affected individuals with PDE10A mutations belonging to a single family were recorded. In addition, Sanger sequencing and in silico analysis were used to identify the mutations. Homozygosity mapping was applied together with whole exome sequencing.

RESULTS

Four individuals from a consanguineous family affected with PDE10A mutations were observed for up to 40 years. Although these individuals displayed a clinical phenotype attributed to the recessive GAF-A mutations, they revealed a bi-allelic GAF-B mutation (c.883G > A:p. D295 N; p.Asp295Asn) that was segregated with all affected individuals. In addition to chorea, we observed peculiar foot deformities and pronounced social phobia, with normal brain MRI. In silico structural analysis suggested that the GAF-B mutation blocked allosteric PDE10A activation. The resulting lack of PDE10A activity likely phenocopies GAF-A mutations, and this is achieved through a distinct mechanism.

CONCLUSIONS

Collectively, our findings demonstrate the association of recessive and dominant phenotypes of known variants, and further expands the genotype-phenotype landscape of PDE10A-associated movement disorders.

Tremor in Parkinson's Disease: From Pathophysiology to Advanced Therapies

Background

Tremor is one of the most prevalent symptoms in Parkinson's Disease (PD). The progression and management of tremor in PD can be challenging, as response to dopaminergic agents might be relatively poor, particularly in patients with tremor-dominant PD compared to the akinetic/rigid subtype. In this review, we aim to highlight recent advances in the underlying pathogenesis and treatment modalities for tremor in PD.

Methods

A structured literature search through Embase was conducted using the terms "Parkinson's Disease" AND "tremor" OR "etiology" OR "management" OR "drug resistance" OR "therapy" OR "rehabilitation" OR "surgery." After initial screening, eligible articles were selected with a focus on published literature in the last 10 years.

Discussion

The underlying pathophysiology of tremor in PD remains complex and incompletely understood. Neurodegeneration of dopaminergic neurons in the retrorubral area, in addition to high-power neural oscillations in the cerebello-thalamo-cortical circuit and the basal ganglia, play a major role. Levodopa is the first-line therapeutic option for all motor symptoms, including tremor. The addition of dopamine agonists or anticholinergics can lead to further tremor reduction. Botulinum toxin injection is an effective alternative for patients with pharmacological-resistant tremor who are not seeking advanced therapies. Deep brain stimulation is the most well-established advanced therapy owing to its long-term efficacy, reversibility, and effectiveness in other motor symptoms and fluctuations. Magnetic resonance-guided focused ultrasound is a promising modality, which has the advantage of being incisionless. Cortical and peripheral electrical stimulation are non-invasive innovatory techniques that have demonstrated good efficacy in suppressing intractable tremor.

Methanol-induced parkinsonism and cerebral vasculopathy due to perfume inhalation

Background

Methanol (methyl alcohol) is a form of toxic alcohol that is found in illicit alcohol as well as household products such as solvents and paint removers. The most common cause of methanol poisoning is through ingestion of adulterated alcohol; however, other routes of poisoning may also occur including cutaneous exposure and, rarely, inhalation.

Methods/results

We are reporting a case of a young woman with vision loss, parkinsonism and widespread cerebral artery spasms due to methanol inhalation from domestically made perfume.

Conclusion

Our case highlights the increased need for awareness on the part of the public and health authorities with regard to the manufacturing and use of homemade perfumes produced with poorly processed alcohol having a high methyl alcohol content.

Clinical, Neurophysiological, Radiological, Pathological, and Genetic Features of Dysferlinopathy in Saudi Arabia

Background

To characterize the phenotypic, neurophysiological, radiological, pathological, and genetic profile of 33 Saudi Arabian families with dysferlinopathy.

Methods

A descriptive observational study was done on a cohort of 112 Saudi Arabian families with LGMD. Screening for the Dysferlin (DYSF) gene was done in a tertiary care referral hospital in Saudi Arabia. Clinical, Neurophysiological, Radiological, Pathological, and Genetic findings in subjects with dysferlin mutation were the primary outcome variables. Statistical analysis was done by Epi-info.

Results

33 out of 112 families (29.46%) registered in the LGMD cohort had Dysferlinopathy. 53 subjects (28 males, 52.83%) from 33 families were followed up for various periods ranging from 1 to 28 years. The mean age of onset was 17.79 ± 3.48 years (Range 10 to 25 years). Miyoshi Myopathy phenotype was observed in 50.94% (27 out of 53), LGMDR2 phenotype in 30.19% (16 out of 53), and proximodistal phenotype in 15.09% (8 out of 53) of the subjects. Loss of ambulation was observed in 39.62% (21 out of 53 subjects). Electrophysiological, Radiological, and histopathological changes were compatible with the diagnosis. Mean serum Creatinine Kinase was 6,464.45 ± 4,149.24 with a range from 302 to 21,483 IU/L. In addition, 13 dysferlin mutations were identified two of them were compound heterozygous. One founder mutation was observed c.164_165insA in 19 unrelated families.

Conclusion

The prevalence of Dysferlinopathy was 29.46% in the native Saudi LGMD cohort. It is the most prevalent subtype seconded by calpainopathy. The clinical course varied among the study subjects and was consistent with those reported from different ethnic groups. One founder mutation was identified. Initial screening of the founder mutations in new families is highly recommended.

Economic Evaluation of Cladribine Tablets in Patients With High Disease Activity-Relapsing-Remitting Multiple Sclerosis in the Kingdom of Saudi Arabia

OBJECTIVE

Cladribine tablets are the first short-course oral treatment approved for high disease activity relapsing-remitting multiple sclerosis (HDA-RRMS) across various countries. This analysis assessed the cost-effectiveness of introducing cladribine tablets as a treatment option for patients with high disease activity compared with other HDA-RRMS therapies in the Kingdom of Saudi Arabia (KSA).

METHODS

The cost-effectiveness model was adapted from the KSA payer's perspective. Data for the model's adaptation were retrieved from the literature and validated by key opinion leaders. The comparators considered in the model were alemtuzumab, dimethyl fumarate, fingolimod, interferon beta-1a (subcutaneous and intramuscular) and beta-1b, natalizumab, and teriflunomide. A sensitivity analysis was also performed to assess the robustness of the analysis.

RESULTS

The cost-effectiveness results showed cladribine tablets as the dominant strategy (ie, less costly and more effective) versus all the comparators. The incremental cost and quality-adjusted life-years gained were largely driven by drug acquisition cost and delayed expanded disability status scale progression, respectively. Cladribine tablets showed an 81% to 100% probability of being cost-effective at a threshold of Saudi Riyal 225 326 per quality-adjusted life-years gained against different comparators.

CONCLUSIONS

Cladribine tablets are a dominant treatment option for patients with HDA-RRMS from the payer perspective in the KSA.

Managing multiple sclerosis in the Covid19 era: a review of the literature and consensus report from a panel of experts in Saudi Arabia

Disease-modifying therapies (DMT) for relapsing-remitting MS (RRMS) act on the immune system, suggesting a need for caution during the SARS-CoV2/Covid-19 pandemic. A group of experts in MS care from Saudi Arabia convened to consider the impact of Covid-19 on MS care in that country, and to develop consensus recommendations on the current application of DMT therapy. Covid-19 has led to disruption to the care of MS in Saudi Arabia as elsewhere. The Expert Panel considered a DMT's overall tolerability/safety profile to be the most important consideration on whether or not to prescribe at this time. Treatment can be started or continued with interferon beta, teriflunomide, dimethyl fumarate, or natalizumab, as these DMTs are not associated with increased risk of infection (there was no consensus on the initiation of other DMTs). A consensus also supported continuing treatment regimens with fingolimod (or siponimod) and cladribine tablets for a patient without active Covid-19. No DMT should be imitated in a patient with active Covid-19, and (only) interferon beta could be continued in the case of Covid-19 infection. Vaccination against Covid-19 is a therapeutic priority for people with MS. New treatment should be delayed for 2–4 weeks for vaccination. Where treatment is already ongoing, vaccination against Covid-19 should be administered immediately without disruption of treatment (first-line DMTs, natalizumab, fingolimod), when lymphocytes have recovered sufficiently (cladribine tablets, alemtuzumab) or 4 months after the last dose (ocrelizumab). These recommendations will need to be refined and updated as new clinical evidence in this area emerges.

Consensus guidelines for botulinum toxin therapy: general algorithms and dosing tables for dystonia and spasticity

Botulinum toxin (BT) therapy is a complex and highly individualised therapy defined by treatment algorithms and injection schemes describing its target muscles and their dosing. Various consensus guidelines have tried to standardise and to improve BT therapy. We wanted to update and improve consensus guidelines by: (1) Acknowledging recent advances of treatment algorithms. (2) Basing dosing tables on statistical analyses of real-life treatment data of 1831 BT injections in 36 different target muscles in 420 dystonia patients and 1593 BT injections in 31 different target muscles in 240 spasticity patients. (3) Providing more detailed dosing data including typical doses, dose variabilities, and dosing limits. (4) Including total doses and target muscle selections for typical clinical entities thus adapting dosing to different aetiologies and pathophysiologies. (5) In addition, providing a brief and concise review of the clinical entity treated together with general principles of its BT therapy. For this, we collaborated with IAB—Interdisciplinary Working Group for Movement Disorders which invited an international panel of experts for the support.

Immune Reconstitution Therapy or Continuous Immunosuppression for the Management of Active Relapsing-Remitting Multiple Sclerosis Patients? A Narrative Review

The majority of disease-modifying drugs (DMDs) available for the management of active relapsing-remitting multiple sclerosis (RMS) depend on continuous drug intake for maintained efficacy, with escalation to a more active drug when an unacceptable level of disease activity returns. Among continuously applied regimens, interferons and glatiramer acetate act as immunomodulators, while dimethyl fumarate, fingolimod, ocrelizumab, natalizumab and teriflunomide are associated with continuous immunosuppression. By contrast, immune reconstitution therapy (IRT) provides efficacy that outlasts a short course of treatment. Autologous hemopoietic stem cell transplantation is perhaps the classic example of IRT, but this invasive and intensive therapy has challenging side-effects. A short treatment course of a pharmacologic agent hypothesized to act as an IRT, such as Cladribine Tablets 3.5 mg/kg or alemtuzumab, can provide long-term suppression of MS disease activity, without need for continuous treatment (the anti-CD20 mechanism of ocrelizumab has the potential to act as an IRT, but is administered continuously, at 6-monthly intervals). Cladribine Tablets 3.5 mg/kg shows some selectivity in targeting adaptive immunity with a lesser effect on innate immunity. The introduction of IRT-like disease-modifying drugs (DMDs) challenges the traditional maintenance/escalation mode of treatment and raises new questions about how disease activity is measured. In this review, we consider a modern classification of DMDs for MS and its implications for the care of patients in the IRT era.

Consensus recommendations for the diagnosis and treatment of multiple sclerosis: 2019 revisions to the MENACTRIMS guidelines

With evolving diagnostic criteria and the advent of new oral and parenteral therapies for MS, most current diagnostic and treatment algorithms need revision and updating. The diagnosis of MS relies on incorporating clinical and paraclinical findings to prove dissemination in space and in time, and exclude alternative diseases that can explain the findings at hand. The differential diagnostic workup should be guided by clinical and laboratory red flags to avoid unnecessary tests. Appropriate selection of multiple sclerosis (MS) therapies is critical to maximize patient benefit. The current guidelines review the scientific evidence supporting treatment of acute relapses, radiologically isolated syndrome, clinically isolated syndrome, relapsing remitting MS, and progressive MS. The purpose of these guidelines is to provide practical recommendations and algorithms for the diagnosis and treatment of MS based on current scientific evidence and clinical experience.

Truncating ARL6IP1 variant as the genetic cause of fatal complicated hereditary spastic paraplegia

Background

Mutations in ARL6IP1, which encodes a tetraspan membrane protein localized to the endoplasmic reticulum (ER), have been recently described in a large family with a complicated form of hereditary spastic paraplegia (HSP).

Case presentation

We sought to expand the HSP phenotype associated with ARL6IP1 variants by examining a Saudi kindred with a clinically more severe presentation, which resulted in spontaneous neonatal death of both affected siblings. Clinical features encompassed not only spastic paraplegia but also developmental delay, microcephaly, cerebral atrophy, periventricular leukoencephalopathy, hypotonia, seizures, spasticity, jejunal stricture, gastrointestinal reflux, neuropathy, dysmorphism and respiratory distress. We performed clinical assessment and radiological studies of this family, in addition to homozygosity mapping and whole exome sequencing (WES) to identify the disease-associated variant. Homozygosity mapping localized the causative gene to a region on chromosome 16 harboring ARL6IP1. WES of the index case identified the homoallelic nonsense variant, c.112C > T in ARL6IP1 that segregated with the phenotype and was predicted to result in loss of the protein. Allelic expression analysis of the parents demonstrated downward pressure on the mutant allele, suggestive of nonsense-mediated decay.

Conclusions

Our report shows that the phenotype associated with ARL6IP1 variants may be broader and more acute than so far reported and identifies fatal HSP as the severe end of the phenotypic spectrum of ARL6IP1 variants.

Lessons Learned from Large-Scale, First-Tier Clinical Exome Sequencing in a Highly Consanguineous Population

We report the results of clinical exome sequencing (CES) on >2,200 previously unpublished Saudi families as a first-tier test. The predominance of autosomal-recessive causes allowed us to make several key observations. We highlight 155 genes that we propose to be recessive, disease-related candidates. We report additional mutational events in 64 previously reported candidates (40 recessive), and these events support their candidacy. We report recessive forms of genes that were previously associated only with dominant disorders and that have phenotypes ranging from consistent with to conspicuously distinct from the known dominant phenotypes. We also report homozygous loss-of-function events that can inform the genetics of complex diseases. We were also able to deduce the likely causal variant in most couples who presented after the loss of one or more children, but we lack samples from those children. Although a similar pattern of mostly recessive causes was observed in the prenatal setting, the higher proportion of loss-of-function events in these cases was notable. The allelic series presented by the wealth of recessive variants greatly expanded the phenotypic expression of the respective genes. We also make important observations about dominant disorders; these observations include the pattern of de novo variants, the identification of 74 candidate dominant, disease-related genes, and the potential confirmation of 21 previously reported candidates. Finally, we describe the influence of a predominantly autosomal-recessive landscape on the clinical utility of rapid sequencing (Flash Exome). Our cohort's genotypic and phenotypic data represent a unique resource that can contribute to improved variant interpretation through data sharing.

Brain MR Imaging Findings in Woodhouse-Sakati Syndrome

BACKGROUND AND PURPOSE

Woodhouse-Sakati syndrome is a rare autosomal recessive disorder characterized by hypogonadism, alopecia, diabetes mellitus, and progressive extrapyramidal signs. The disease is caused by biallelic pathogenic variants in the DCAF17 gene. The purpose of this study was to describe the spectrum of brain MR imaging abnormalities in Woodhouse-Sakati syndrome.

MATERIALS AND METHODS

We reviewed brain MR images of 26 patients with a clinical and genetic diagnosis of Woodhouse-Sakati syndrome (12 males, 14 females; age range, 16-45 years; mean age, 26.6 years). Follow-up studies were conducted for 6 patients.

RESULTS

All patients had abnormal MR imaging findings. The most common abnormalities were a small pituitary gland (76.9%), pronounced basal ganglia iron deposition (73%), and white matter lesions in 69.2%. White matter lesions showed frontoparietal and periventricular predominance. All white matter lesions spared subcortical U-fibers and were nonenhanced. Prominent perivascular spaces (15.3%) and restricted diffusion in the splenium of the corpus callosum (7.6%) were less frequent findings. Follow-up studies showed expansion of white matter lesions with iron deposition further involving the red nucleus and substantia nigra. Older age was associated with a more severe degree of white matter lesions (P < .001).

CONCLUSIONS

Small pituitary gland, accentuated iron deposition in the globus pallidus, and nonenhancing frontoparietal/periventricular white matter lesions were the most noted abnormalities seen in our cohort. The pattern and extent of these findings were observed to correlate with older age, reflecting a possible progressive myelin destruction and/or axonal loss. The presence of pituitary hypoplasia and white matter lesions can further distinguish Woodhouse-Sakati syndrome from other neurodegenerative diseases with brain iron accumulation subtypes.

Identification of a novel genetic locus underlying tremor and dystonia

BACKGROUND

Five affected individuals with syndromic tremulous dystonia, spasticity, and white matter disease from a consanguineous extended family covering a period of over 24 years are presented. A positional cloning approach utilizing genome-wide linkage, homozygozity mapping and whole exome sequencing was used for genetic characterization. The impact of a calmodulin-binding transcription activator 2, (CAMTA2) isoform 2, hypomorphic mutation on mRNA and protein abundance was studied using fluorescent reporter expression cassettes. Human brain sub-region cDNA libraries were used to study the expression pattern of CAMTA2 transcript variants.

RESULTS

Linkage analysis and homozygozity mapping localized the disease allele to a 2.1 Mb interval on chromosome 17 with a LOD score of 4.58. Whole exome sequencing identified a G>A change in the transcript variant 2 5'UTR of CAMTA2 that was only 6 bases upstream of the translation start site (c.-6G > A) (NM_001171166.1) and segregated with disease in an autosomal recessive manner. Transfection of wild type and mutant 5'UTR-linked fluorescent reporters showed no impact upon mRNA levels but a significant reduction in the protein fluorescent activity implying translation inhibition.

CONCLUSIONS

Mutation of CAMTA2 resulting in post-transcriptional inhibition of its own gene activity likely underlies a novel syndromic tremulous dystonia.

The ALS-linked E102Q mutation in Sigma receptor-1 leads to ER stress-mediated defects in protein homeostasis and dysregulation of RNA-binding proteins

Amyotrophic lateral sclerosis (ALS) is characterized by the selective degeneration of motor neurons (MNs) and their target muscles. Misfolded proteins which often form intracellular aggregates are a pathological hallmark of ALS. Disruption of the functional interplay between protein degradation (ubiquitin proteasome system and autophagy) and RNA-binding protein homeostasis has recently been suggested as an integrated model that merges several ALS-associated proteins into a common pathophysiological pathway. The E102Q mutation in one such candidate gene, the endoplasmic reticulum (ER) chaperone Sigma receptor-1 (SigR1), has been reported to cause juvenile ALS. Although loss of SigR1 protein contributes to neurodegeneration in several ways, the molecular mechanisms underlying E102Q-SigR1-mediated neurodegeneration are still unclear. In the present study, we showed that the E102Q-SigR1 protein rapidly aggregates and accumulates in the ER and associated compartments in transfected cells, leading to structural alterations of the ER, nuclear envelope and mitochondria and to subsequent defects in proteasomal degradation and calcium homeostasis. ER defects and proteotoxic stress generated by E102Q-SigR1 aggregates further induce autophagy impairment, accumulation of stress granules and cytoplasmic aggregation of the ALS-linked RNA-binding proteins (RBPs) matrin-3, FUS, and TDP-43. Similar ultrastructural abnormalities as well as altered protein degradation and misregulated RBP homeostasis were observed in primary lymphoblastoid cells (PLCs) derived from E102Q-SigR1 fALS patients. Consistent with these findings, lumbar α-MNs of both sALS as well as fALS patients showed cytoplasmic matrin-3 aggregates which were not co-localized with pTDP-43 aggregates. Taken together, our results support the notion that E102Q-SigR1-mediated ALS pathogenesis comprises a synergistic mechanism of both toxic gain and loss of function involving a vicious circle of altered ER function, impaired protein homeostasis and defective RBPs.

Ultrasound-guided botulinum toxin A injection in the treatment of belly dancer's dyskinesia

Background

Belly dancer’s dyskinesia is an extremely rare condition. It manifests as semicontinuous, slow, writhing, sinuous abdominal wall movements that are bothersome to the patient. Management of this condition is extremely difficult and challenging.

Methods

We describe four patients with belly dancer’s dyskinesia who were treated with Botulinum Toxin A (BTX) injections under ultrasound guidance.

Results

All patients underwent the same BTX injection procedure using an aseptic technique under ultrasound guidance. The patients responded well to the BTX injections after an unsatisfactory course of medical treatment. The patients reported complete abolishment of abnormal abdominal movements with no side effects.

Conclusions

We report a cohort of patients with belly dancer dyskinesia treated successfully with BTX injections. Ultrasound guidance for injections increases the accuracy and reduces the risk of the complications. BTX injection under ultrasound guidance is a safe and effective treatment modality that should be employed as a first-line in the management of patients with belly dancer’s dyskinesia.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-016-0746-5) contains supplementary material, which is available to authorized users.

A first-line diagnostic assay for limb-girdle muscular dystrophy and other myopathies

Background

Fifty random genetically unstudied families (limb-girdle muscular dystrophy (LGMD)/myopathy) were screened with a gene panel incorporating 759 OMIM genes associated with neurological disorders. Average coverage of the CDS and 10 bp flanking regions of genes was 99 %. All families were referred to the Neurosciences Clinic of King Faisal Specialist Hospital and Research Centre, Saudi Arabia. Patients presented with muscle weakness affecting the pelvic and shoulder girdle. Muscle biopsy in all cases showed dystrophic or myopathic changes. Our main objective was to evaluate a neurological gene panel as a first-line diagnostic test for LGMD/myopathies.

Results

Our panel identified the mutation in 76 % of families (38/50; 11 novel). Thirty-four families had mutations in LGMD-related genes with four others having variants not typically associated with LGMD. The majority of cases had recessive inheritance with homoallelic pathogenic variants (97.4 %, 37/38), as expected considering the high rate of consanguinity in the study population. In one case, we detected a heterozygous mutation in DNAJB responsible for LGMD-1E. Our cohort included seven different subtypes of LGMD2. Mutations of DYSF were the most commonly identified cause of disease followed by that in CAPN3 and FKRP. Non-LGMD myopathies were due to mutations in genes associated with congenital disorder of glycosylation (ALG2), rigid spine muscular dystrophy 1 (SEPN1), inclusion body myopathy2/Nonaka myopathy (GNE), and neuropathy (WNK1). Whole exome sequencing (WES) of patients who remained undiagnosed with the neurological panel did not improve our diagnostic yield.

Conclusions

Our neurological panel achieved a high clinical sensitivity (76 %) and is an effective first-line laboratory test in patients with LGMD and other myopathies. This sensitive, cost-effective, and rapid assay significantly assists clinical practice especially in these phenotypically and genetically heterogeneous disorders. Moreover, the application of the American College of Medical Genetics (ACMG) and Association for Molecular Pathology (AMP) guidelines applied in the classification of variant pathogenecity provides a clear interpretation for physicians on the relevance of such findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s40246-016-0089-8) contains supplementary material, which is available to authorized users.

Ataxia and Hypogonadotropic Hypogonadism with Intrafamilial Variability Caused by RNF216 Mutation

Gordon Holmes syndrome (GHS) is a distinct phenotype of autosomal recessive cerebellar ataxia, characterized by ataxia, dementia, reproductive defects and hypogonadism; it has been recently found to be associated with RNF216 mutation. We performed whole-exome sequencing and filtered the resulting novel variants by the coordinates of the shared autozygome. We identified a novel splicing variant in RNF216 that is likely to abolish the canonical splice site at the junction of exon/intron 13 (NM_207111.3:c.2061G>A). We herein report two patients with GHS caused by a novel RNF216 mutation as the first follow up report on RNF216-related GHS, and show interfamilial variability of phenotype supporting the previously reported RNF216-related cases.

Woodhouse-Sakati Syndrome: Report of the First Tunisian Family with the C2orf37 Gene Mutation

Woodhouse-Sakati syndrome (WSS) is an infrequent autosomal recessive condition characterized by progressive extrapyramidal signs, mental retardation, hypogonadism, alopecia, and diabetes mellitus. This syndrome belongs to a heterogeneous group of inherited neurodegenerative disorders characterized iron accumulation in the brain, and it is caused by mutations of the C2orf37 gene. We report the first Tunisian family with two affected sisters presenting with a phenotype suggestive of WSS. We examined the index patient presenting with movement disorders and mental retardation and then searched for similar cases in her family, which identified a sister with similar signs. We performed a genetic study that confirmed the diagnosis and revealed a c.436delC mutation of the C2orf37 gene. Therefore, WSS is an important consideration in patients presenting with movement disorders and intellectual disability. A high consanguinity contributes to the clustering of such rare autosomal recessive syndromes.