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.

Multimodal Evoked Potential Profiles in Woodhouse-Sakati Syndrome.

PURPOSE: Woodhouse-Sakati syndrome is a rare autosomal recessive syndrome caused by homozygous mutations in the DCAF17 gene, characterized by marked neurologic and endocrine manifestations in the setting of brain iron accumulation and white matter lesions on neuroimaging. Here, we report electrophysiologic profiles in Woodhouse-Sakati syndrome and their possible value in understanding disease pathophysiology and phenotypic variability. METHODS: Thirteen genetically confirmed Woodhouse-Sakati syndrome patients were evaluated via different evoked potential (EP) modalities, including brainstem auditory EPs, pattern reversal visual EPs, and somatosensory EPs to tibial and/or median nerves. RESULTS: All EP modalities showed variable abnormalities. Pattern reversal visual EPs were recorded in all patients, with nine patients exhibiting abnormal results. From those, seven patients showed prolonged P100 latencies after stimulation of right and left eyes for each in turn. Two patients showed P100 latency abnormality after single eye stimulation recorded from midoccipital electrode. Median somatosensory EPs were recorded in 10 patients, with 6 patients having a prolonged cortical N19 response. Tibial somatosensory EP was performed for 11 patients, and 8 patients showed abnormal results where P37 cortical response was absent or prolonged, whereas peripheral potentials at the popliteal fossa were normal. Brainstem auditory EPs were abnormal only in two patients, with prolonged wave III and V latencies. Five patients with hearing impairment presented with normal brainstem auditory EP results. CONCLUSIONS: Multiple EP abnormalities are observed in Woodhouse-Sakati syndrome patients, mainly in pattern reversal visual EPs and somatosensory EPs. These findings indicate potential myelin dysfunction that has a role in the underlying pathophysiology, disease course, and phenotypic variability.

MENACTRIMS practice guideline for COVID-19 vaccination in patients with multiple sclerosis.

Patients with multiple sclerosis (MS) should be vaccinated against COVID-19. All COVID-19 vaccines are effective and do not appear to carry any additional risk for patients with MS. Patients with MS should get a COVID-19 vaccine as soon as it becomes available. The risks of COVID-19 disease outweigh any potential risks from the vaccine. Even if vaccinated, patients with MS should continue to practice standard and recommended precautions against COVID-19, such as wearing a face mask, social distancing and washing hands. There is no evidence that patients with MS are at higher risk of complications from the mRNA, non-replicating viral vector, inactivated virus or protein COVID-19 vaccines, compared to the general population. COVID-19 Vaccines are safe to use in patients with MS treated with disease-modifying therapies (DMTs). The effectiveness of vaccination may be affected by few of the DMTs but yet some protection is still provided. For certain DMTs we may consider coordinating the timing of the vaccine with the timing of the DMT dose to increase vaccine efficacy.

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.

A Prospective Multicenter Study for Assessing MusiQoL Validity among Arabic-Speaking MS Patients Treated with Subcutaneous Interferon ß-1a.

Few studies examine health-related quality of life (HRQoL) in Arabic-speaking multiple sclerosis (MS) patients. However, HRQoL tools such as the Short Form-36 QoL instrument (SF-36) and the Multiple Sclerosis International QoL (MusiQoL) questionnaire have been validated in other languages. The primary objective of this study was to prospectively assess HRQoL using the MusiQoL questionnaire among Arabic-speaking MS patients treated with subcutaneous interferon (sc IFN ß-1a) over 12 months, as part of a prospective, multinational, multicenter cohort study. Patients' clinical parameters and HRQoL were assessed at baseline, 6 months, and 12 months. Changes in MusiQoL total and subdomain scores were compared using a Friedman test. Correlation between MusiQoL total score and Expanded Disability Status Score (EDSS) was also evaluated. In total, 439 patients from four Arabic-speaking countries were included. The mean age was 32.44 (±0.34) years, 71.5% were female, and 63.1% had an education level of university or above. The mean MS duration was 4.13 (±0.12) years, mean age at first attack was 27.35 (±0.26) years, and mean baseline EDSS score was 2.05 (±0.04). MusiQoL total score significantly improved at 6 months; however, this diminished at 12 months (65.67 ± 0.8 at baseline vs. 67.21 ± 0.79 at 6 months and 65.75 ± 0.8 at 12 months; p = 0.0015). Several aspects of patients' HRQoL including activity of daily living, physical well-being, symptoms, and coping improved. Overall HRQoL measured using SF-36 remained generally unchanged over time (p = 0.215). There was a statistically significant inverse relationship between change in EDSS score over time and change in overall MusiQoL score over time. In summary, findings confirm the utility of using MusiQoL for assessing changes in HRQoL during treatment with sc IFN ß-1a in Arabic-speaking patients with MS.

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.

Family Planning for People with Multiple Sclerosis in Saudi Arabia: an Expert Consensus.

More than half of all patients with multiple sclerosis (MS) in the Kingdom of Saudi Arabia (KSA) are women of childbearing age. Raising a family is an important life goal for women in our region of the world. However, fears and misconceptions about the clinical course of relapsing-remitting MS (RRMS) and the effects of disease-modifying drugs (DMDs) on the foetus have led many women to reduce their expectations of raising a family, sometimes even to the point of avoiding pregnancy altogether. The increase in the number of DMDs available to manage RRMS and recent studies on their effects in pregnancy have broadened management options for these women. Interferon beta now has an indication in Europe for use during pregnancy (according to clinical need) and can be used during breastfeeding. Glatiramer acetate is a further possible option for women with lower levels of RRMS disease activity who are, or about to become, pregnant; natalizumab may be used up to 30 weeks in patients with higher levels of disease activity. Where possible, physicians need to support and encourage women to pursue their dream of a fulfilling family life, supported where necessary by active interventions for RRMS that are increasingly evidence based.

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.

Cladribine Tablets and Relapsing-Remitting Multiple Sclerosis: A Pragmatic, Narrative Review of What Physicians Need to Know.

Immune reconstitution therapy (IRT) is an emerging management concept for multiple sclerosis, whereby a short course of treatment provides long-lasting suppression of disease activity. "Cladribine tablets 10 mg" refers to a total cumulative dose of cladribine given over 2 years (henceforth referred to as cladribine tablets 3.5 mg/kg); it is a relatively new treatment option that is hypothesised to act as an IRT acting preferentially on the adaptive immune system. A randomised, 2-year, placebo-controlled trial (CLARITY) showed that treatment with cladribine tablets reduced indices of disease activity (relapses, lesions on magnetic resonance images, disability progression) and that this effect outlasted the pharmacologic effect of the treatment on the immune system (mainly a reduction in circulating B and T cells, with little effect on components of the innate immune system such as monocytes). CLARITY Extension, a 2-year extension to this trial, demonstrated durable efficacy, also in patients who received the standard 2-year course of cladribine tablets 3.5 mg/kg and were re-randomised to placebo for a further 2 years. Relative risk reductions for relapse rate with cladribine tablets 3.5 mg/kg were similar for patients with or without prior high disease activity. Reductions in disability progression with cladribine tablets 3.5 mg/kg were higher in patients with prior high relapse rates with or without prior treatment non-response. In this review, we describe the therapeutic profile of cladribine tablets 3.5 mg/kg and provide practical information on initiating this treatment option in the most appropriate patients.

Patterns of neurological manifestations in Woodhouse-Sakati Syndrome.

BACKGROUND: Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive disease with characteristic neuro-endocrine manifestations. WSS encompasses heterogeneous phenotypes and disease course. OBJECTIVE: We aimed to characterize neurological involvement of the disease through subgrouping of core neurological manifestations. METHODS: A single-institution retrospective analysis of patients with clinically and genetically confirmed diagnosis of WSS. RESULTS: A total of 38 individuals belonging to 17 families were identified to have WSS. The mean age at enrollment was 30.1 years (range 16-53 years). Neurological involvement was noted in 31 patients (81.5%). Dystonia was the most common neurological manifestation (67%), followed by intellectual disability (45%) and sensorineural hearing loss (30%). Based on the Neurological Impairment Scale (NIS), the disease was recognized to have two distinct patterns. A disabling, rapidly progressive pattern (NIS of 3-4; Type 1) was noted in eighteen patients (12 males, 6 females; 47.4%) with severe disability that occurs within a mean duration of 7.4 ±â€¯3.6 years. Type 2 WSS was identified in twenty patients (8 males, 12 females; 52.6%), and showed either absent or mild neurological involvement with preserved activities of daily living (NIS of 0-1). The mean age of onset for neurological manifestations was earlier in type 1 (12.6 ±â€¯4.5 years) compared to type 2 (18.1 ±â€¯4.3 years). Type 1 WSS has a significantly higher rate of intellectual disability (p= <0.001). CONCLUSIONS: In this pleiotropic syndrome, we identified two distinct phenotypes with variable prognosis. A high Interfamilial and intrafamilial phenotypic variability despite having a similar gene mutation suggests a possible role of genetic or environmental modifying factor.

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.

Autosomal recessive ADCY5-Related dystonia and myoclonus: Expanding the genetic spectrum of ADCY5-Related movement disorders.

INTRODUCTION: ADCY5-related hyperkinesia encompasses a heterogeneous group of phenotypes, including paroxysmal chorea, myoclonus, and dystonia. The disease is attributed to mutations of ADCY5, which encodes an adenylate cyclase enzyme. The disease can occur in a sporadic or familial pattern. With exception of one study, all reports on familial ADCY5-related hyperkinesia were associated with an autosomal dominant inheritance. Herein, we describe a native Arabian Bedouin family with an autosomal recessive ADCY5-related disorder and expand the genotypic and phenotypic spectrum of this disorder. METHODS: The pedigree included 4 generations of a family with 6 affected individuals. The patients were examined clinically and radiologically. Homozygosity mapping and Whole Exome Sequencing (WES) were used to identify a variant, predicted to be pathogenic, which segregated with disease in this family. RESULTS: All patients presented with early-onset dystonia and myoclonus. The patients had delayed motor and language milestones, axial hypotonia, severe anxiety, social phobia, and isolation. One patient had dilated cardiomyopathy. WES of one affected individual revealed a novel homozygous missense mutation (c.1762G > A, p.D588N) of ADCY5, that segregated with disease in an autosomal recessive manner, and was absent in more than 1000 ethnically-matched chromosomes. The mutation replaces a highly conserved nucleotide and is predicted to be deleterious. CONCLUSION: This study reports the second family with autosomal recessive childhood-onset ADCY5-related disorder and expands our understanding of phenotype/genotype correlations of this disorder.