Bi-allelic PRRT2 variants may predispose to Self-limited Familial Infantile Epilepsy.

Heterozygous PRRT2 variants are frequently implicated in Self-limited Infantile Epilepsy, whereas homozygous variants are so far linked to severe presentations including developmental and epileptic encephalopathy, movement disorders, and intellectual disability. In a study aiming to explore the genetics of epilepsy in the Sudanese population, we investigated several families including a consanguineous family with three siblings diagnosed with self-limited infantile epilepsy. We evaluated both dominant and recessive inheritance using whole exome sequencing and genomic arrays. We identified a pathogenic homozygous splice-site variant in the first intron of PRRT2 [NC_000016.10(NM_145239.3):c.-65-1G > A] that segregated with the phenotype in this family. This work taps into the genetics of epilepsy in an underrepresented African population and suggests that the phenotypes of homozygous PRRT2 variants may include milder epilepsy presentations without movement disorders.

Spontaneous triple vessel cervicocephalic artery dissection in a young gentleman: A case report.

INTRODUCTION: Cervicocephalic arterial dissections (CADs) occur in 3 cases per 100,000 individuals across all ages. Multiple simultaneous CADs are found in 13 to 22% of cases, and three or more dissections occur in approximately 2%. CADs might result from multifactorial intrinsic deficiencies of vessel wall integrity and extrinsic factors, e.g., minor trauma. CASE PRESENTATION: A young gentleman presented to the emergency department with a sudden onset of a spinning sensation of surrounding, left side arm weakness, blurring of vision, and an NIHSS score of 4. An urgent CT scan of the head and intracranial angiogram showed bilateral severe stenosis of the distal cervical segment of internal carotid arteries (ICAs) and right vertebral artery moderate stenosis at the V2 segment. He had been given IV TPA (Alteplase) within the 4.5-hour window. After 4 hours, the patient's GCS dropped from 15 to 10, and the NIHSS score increased from 4 to 24, followed by witnessed a generalized tonic-clonic seizure. Repeat urgent CT head showed no evidence of intracerebral hemorrhage (ICH). The patient was arranged for cerebral angiographic catheterization that showed bilateral flame-shaped occlusion of cervical ICA dissection. There is a mild focal narrowing of the right cervical vertebral artery, likely dissection. Routine laboratory blood workup for vasculitis was negative. During MICU admission, he had witnessed the right arm hemichorea-ballism spectrum abnormal movement. After the 6th-month follow-up, intracranial CT angiogram showed reduced caliber of the bilateral distal cervical course of the internal carotid arteries seen with residual dissection and focal outpouching of the right ICA representing pseudoaneurysm. DISCUSSION: The occurrence of multiple CADs suggests the presence of an underlying intrinsic arteriopathy, such as FMD, the presence of pseudoaneurysm, environmental triggers, cervical manipulation, and remote history of head or neck surgery. A study of the most extensive case series of patients with cervical artery dissection showed 15.2% of patients with multiple CAD. In most patients with multiple cervical artery dissections, antithrombotic treatment is effective, complete recanalization, and the outcome is favorable. Outside the window period of acute ischemic stroke, either anticoagulation or antiplatelet therapy is a recognized treatment for secondary ischemic stroke prevention due to extracranial artery dissection. For acute stroke or TIA patients caused by intracranial artery dissection, experts recommend antiplatelet therapy rather than anticoagulation. CONCLUSION: Simultaneous triple-vessel cervicocephalic arterial dissections are rarely reported condition. Multiple CADs are associated with underlying vasculopathy and environmental triggers, and a majority are recanalized with antithrombotic treatment with favorable outcomes. Antithrombotic treatment is effective in most patients with multiple CADs, and most expect complete recanalization. This case report guides physicians in the treatment and outcome of acute stroke due to multiple CAD.

PLA2G6-associated late-onset parkinsonism in a Sudanese family.

INTRODUCTION: The phospholipase A2 group VI gene (PLA2G6) encodes an enzyme that catalyzes the hydrolytic release of fatty acids from phospholipids. Four neurological disorders with infantile, juvenile, or early adult-onset are associated with PLA2G6 genetic alterations, namely infantile neuroaxonal dystrophy (INAD), atypical neuroaxonal dystrophy (ANAD), dystonia-parkinsonism (DP), and autosomal recessive early-onset parkinsonism (AREP). Few studies in Africa reported PLA2G6-associated disorders and none with parkinsonism of late adult onset. MATERIAL AND METHODS: The patients were clinically assessed following UK Brain Bank diagnostic criteria and International Parkinson and Movement Disorder Society's Unified Parkinson's Disease Rating Scale (MDS-UPDRS). Brain MRI without contrast was performed. Genetic testing was done using a custom-made Twist panel, screening 34 known genes, 27 risk factors, and 8 candidate genes associated with parkinsonism. Filtered variants were PCR-amplified and validated using Sanger sequencing and also tested in additional family members to study their segregation. RESULT: Two siblings born to consanguineous parents developed parkinsonism at the age of 58 and 60 years, respectively. MRI showed an enlarged right hippocampus in patient 2, but no overt abnormalities indicative of INAD or iron deposits. We found two heterozygous variants in PLA2G6, an in-frame deletion NM_003560:c.2070_2072del (p.Val691del) and a missense variant NM_003560:c.956C>T (p.Thr319Met). Both variants were classified as pathogenic. CONCLUSION: This is the first case in which PLA2G6 is associated with late-onset parkinsonism. Functional analysis is needed to confirm the dual effect of both variants on the structure and function of iPLA2ß.

Clinical phenotyping and genetic diagnosis of a large cohort of Sudanese families with hereditary spinocerebellar degenerations.

Hereditary spinocerebellar degenerations (SCDs) is an umbrella term that covers a group of monogenic conditions that share common pathogenic mechanisms and include hereditary spastic paraplegia (HSP), cerebellar ataxia, and spinocerebellar ataxia. They are often complicated with axonal neuropathy and/or intellectual impairment and overlap with many neurological conditions, including neurodevelopmental disorders. More than 200 genes and loci inherited through all modes of Mendelian inheritance are known. Autosomal recessive inheritance predominates in consanguineous communities; however, autosomal dominant and X-linked inheritance can also occur. Sudan is inhabited by genetically diverse populations, yet it has high consanguinity rates. We used next-generation sequencing, genotyping, bioinformatics analysis, and candidate gene approaches to study 90 affected patients from 38 unrelated Sudanese families segregating multiple forms of SCDs. The age-at-onset in our cohort ranged from birth to 35 years; however, most patients manifested childhood-onset diseases (the mean and median ages at onset were 7.5 and 3 years, respectively). We reached the genetic diagnosis in 63% and possibly up to 73% of the studied families when considering variants of unknown significance. Combining the present data with our previous analysis of 25 Sudanese HSP families, the success rate reached 52-59% (31-35/59 families). In this article we report candidate variants in genes previously known to be associated with SCDs or other phenotypically related monogenic disorders. We also highlight the genetic and clinical heterogeneity of SCDs in Sudan, as we did not identify a major causative gene in our cohort, and the potential for discovering novel SCD genes in this population.

COVID-19 Vaccine as a Potential Triggering Factor for Anti-Glomerular Basement Membrane (GBM) Disease: A Case Report and Literature Review.

Coronavirus 2019 (COVID-19) is considered one of the most significant medical pandemics of this century, with high morbidity and mortality associated with the pandemic. The virus was recognized initially as a cause of pneumonia, but subsequent studies showed significant association with gastrointestinal, neurological, and autoimmune diseases. By 2020, several vaccines became available for use, significantly reducing the infection rate. A good safety profile supported most of the studies related to vaccines. However, this area is still under study, and some reports linked the COVID-19 vaccine to the development of thrombocytopenia, thrombosis, Guillain-Barre syndrome, autoimmune diseases, and myocarditis. These side effects need to be reported to VAERS (Vaccine Adverse Event Reporting System). The exact etiology of anti-glomerular basement (Anti-GBM) disease remains unknown, but the disease is thought to be triggered by environmental factors in genetically predisposed individuals. It is considered one of the serious diseases that could lead to permanent kidney impairment if not treated early and adequately. That's why a great effort is being made by health care practitioners to figure out and avoid the risk and triggering factors. Few previously published papers linked the COVID-19 vaccine and the development of anti-GBM disease, which raised concerns about digging more into this area. Herein, we are reporting a case of a patient who developed rapidly progressive glomerulonephritis (RPGN) due to anti-glomerular basement membrane (GBM) antibody disease two days after receiving the second dose of the COVID-19 vaccine.

Genetic diagnosis in Sudanese and Tunisian families with syndromic intellectual disability through exome sequencing.

BACKGROUND: Intellectual disability is a form of neurodevelopmental disorders that begin in childhood and is characterized by substantial intellectual difficulties as well as difficulties in conceptual, social, and practical areas of living. Several genetic and nongenetic factors contribute to its development; however, its most severe forms are generally attributed to single-gene defects. High-throughput technologies and data sharing contributed to the diagnosis of hundreds of single-gene intellectual disability subtypes. METHOD: We applied exome sequencing to identify potential variants causing syndromic intellectual disability in six Sudanese patients from four unrelated families. Data sharing through the Varsome portal corroborated the diagnosis of one of these patients and a Tunisian patient investigated through exome sequencing. Sanger sequencing validated the identified variants and their segregation with the phenotypes in the five studied families. RESULT: We identified three pathogenic/likely pathogenic variants in CCDC82, ADAT3, and HUWE1 and variants of uncertain significance in HERC2 and ATP2B3. The patients with the CCDC82 variants had microcephaly and spasticity, two signs absent in the two previously reported families with CCDC82-related intellectual disability. CONCLUSION: In conclusion, we report new patients with pathogenic mutations in the genes CCDC82, ADAT3, and HUWE1. We also highlight the possibility of extending the CCDC82-linked phenotype to include spastic paraplegia and microcephaly.

Insights into Clinical, Genetic, and Pathological Aspects of Hereditary Spastic Paraplegias: A Comprehensive Overview.

Hereditary spastic paraplegias (HSP) are a heterogeneous group of motor neurodegenerative disorders that have the core clinical presentation of pyramidal syndrome which starts typically in the lower limbs. They can present as pure or complex forms with all classical modes of monogenic inheritance reported. To date, there are more than 100 loci/88 spastic paraplegia genes (SPG) involved in the pathogenesis of HSP. New patterns of inheritance are being increasingly identified in this era of huge advances in genetic and functional studies. A wide range of clinical symptoms and signs are now reported to complicate HSP with increasing overall complexity of the clinical presentations considered as HSP. This is especially true with the emergence of multiple HSP phenotypes that are situated in the borderline zone with other neurogenetic disorders. The genetic diagnostic approaches and the utilized techniques leave a diagnostic gap of 25% in the best studies. In this review, we summarize the known types of HSP with special focus on those in which spasticity is the principal clinical phenotype ("SPGn" designation). We discuss their modes of inheritance, clinical phenotypes, underlying genetics, and molecular pathways, providing some observations about therapeutic opportunities gained from animal models and functional studies. This review may pave the way for more analytic approaches that take into consideration the overall picture of HSP. It will shed light on subtle associations that can explain the occurrence of the disease and allow a better understanding of its observed variations. This should help in the identification of future biomarkers, predictors of disease onset and progression, and treatments for both better functional outcomes and quality of life.

Pathogenic Variants in ABHD16A Cause a Novel Psychomotor Developmental Disorder With Spastic Paraplegia.

Introduction: Hereditary spastic paraplegia is a clinically and genetically heterogeneous neurological entity that includes more than 80 disorders which share lower limb spasticity as a common feature. Abnormalities in multiple cellular processes are implicated in their pathogenesis, including lipid metabolism; but still 40% of the patients are undiagnosed. Our goal was to identify the disease-causing variants in Sudanese families excluded for known genetic causes and describe a novel clinico-genetic entity. Methods: We studied four patients from two unrelated consanguineous Sudanese families who manifested a neurological phenotype characterized by spasticity, psychomotor developmental delay and/or regression, and intellectual impairment. We applied next-generation sequencing, bioinformatics analysis, and Sanger sequencing to identify the genetic culprit. We then explored the consequences of the identified variants in patients-derived fibroblasts using targeted-lipidomics strategies. Results and Discussion: Two homozygous variants in ABHD16A segregated with the disease in the two studied families. ABHD16A encodes the main brain phosphatidylserine hydrolase. In vitro, we confirmed that ABHD16A loss of function reduces the levels of certain long-chain lysophosphatidylserine species while increases the levels of multiple phosphatidylserine species in patient's fibroblasts. Conclusion: ABHD16A loss of function is implicated in the pathogenesis of a novel form of complex hereditary spastic paraplegia.

Hereditary spastic paraplegias: time for an objective case definition and a new nosology for neurogenetic disorders to facilitate biomarker/therapeutic studies.

INTRODUCTION: Hereditary spastic paraplegias (HSPs) are heterogeneous neurodegenerative disorders characterized by progressive lower limb weakness and spasticity as core symptoms of the degeneration of the corticospinal motor neurons. Even after exclusion of infectious and toxic mimickers of these disorders, the definitive diagnosis remains tricky, mainly in sporadic forms, as there is significant overlap with other disorders. Since their first description, various attempts failed to reach an appropriate classification. This was due to the constant expansion of the clinical spectrum of these diseases and the discovery of new genes, a significant number of them was involved in overlapping diseases. Areas covered: In this perspective review, an extensive literature study was conducted on the historical progress of HSP research. We also revised the previous and the current classifications of HSP and the closely related neurogenetic disorders and analyzed the areas of overlap. Expert opinion: There is undeniable need for objective case definition and reclassification of all neurogenetic disorders including HSPs, a prerequisite to improve patient follow-up, biomarker identification and develop therapeutics. The challenge is to understand why mutations can give rise to multiple phenotypic presentations along this spectrum of diseases in which the corticospinal tract is affected.