Genetic Appraisal of Hereditary Muscle Disorders In A Cohort From Mumbai, India.

BACKGROUND: Hereditary muscle disorders are clinically and genetically heterogeneous. Limited information is available on their genetic makeup and their prevalence in India. OBJECTIVE: To study the genetic basis of prevalent hereditary myopathies. MATERIAL AND METHODS: This is a retrospective study conducted at a tertiary care center. The study was approved by the institutional ethics board. The point of the collection was the genetic database. The genetic data of myopathy patients for the period of two and half years (2019 to mid-2021) was evaluated. Those with genetic diagnoses of DMD, FSHD, myotonic dystrophies, mitochondriopathies, and acquired myopathies were excluded. The main outcome measures were diagnostic yield and the subtype prevalence with their gene variant spectrum. RESULTS: The definitive diagnostic yield of the study was 39% (cases with two pathogenic variants in the disease-causing gene). The major contributing genes were GNE (15%), DYSF (13%), and CAPN3 (7%). Founder genes were documented in Calpainopathy and GNE myopathy. The uncommon myopathies identified were Laminopathy (0.9%), desminopathy (0.9%), and GMPPB-related myopathy (1.9%). Interestingly, a small number of patients showed pathogenic variants in more than one myopathy gene, the multigenic myopathies. CONCLUSION: This cohort study gives hospital-based information on the prevalent genotypes of myopathies (GNE, Dysferlinopathy, and calpainopathy), founder mutations, and also newly documents the curious occurrence of multigenicity in a small number of myopathies.

Clinical and Genomic Evaluation of 207 Genetic Myopathies in the Indian Subcontinent.

Objective: Inherited myopathies comprise more than 200 different individually rare disease-subtypes, but when combined together they have a high prevalence of 1 in 6,000 individuals across the world. Our goal was to determine for the first time the clinical- and gene-variant spectrum of genetic myopathies in a substantial cohort study of the Indian subcontinent. Methods: In this cohort study, we performed the first large clinical exome sequencing (ES) study with phenotype correlation on 207 clinically well-characterized inherited myopathy-suspected patients from the Indian subcontinent with diverse ethnicities. Results: Clinical-correlation driven definitive molecular diagnosis was established in 49% (101 cases; 95% CI, 42-56%) of patients with the major contributing pathogenicity in either of three genes, GNE (28%; GNE-myopathy), DYSF (25%; Dysferlinopathy), and CAPN3 (19%; Calpainopathy). We identified 65 variant alleles comprising 37 unique variants in these three major genes. Seventy-eight percent of the DYSF patients were homozygous for the detected pathogenic variant, suggesting the need for carrier-testing for autosomal-recessive disorders like Dysferlinopathy that are common in India. We describe the observed clinical spectrum of myopathies including uncommon and rare subtypes in India: Sarcoglycanopathies (SGCA/B/D/G), Collagenopathy (COL6A1/2/3), Anoctaminopathy (ANO5), telethoninopathy (TCAP), Pompe-disease (GAA), Myoadenylate-deaminase-deficiency-myopathy (AMPD1), myotilinopathy (MYOT), laminopathy (LMNA), HSP40-proteinopathy (DNAJB6), Emery-Dreifuss-muscular-dystrophy (EMD), Filaminopathy (FLNC), TRIM32-proteinopathy (TRIM32), POMT1-proteinopathy (POMT1), and Merosin-deficiency-congenital-muscular-dystrophy-type-1 (LAMA2). Thirteen patients harbored pathogenic variants in >1 gene and had unusual clinical features suggesting a possible role of synergistic-heterozygosity/digenic-contribution to disease presentation and progression. Conclusions: Application of clinically correlated ES to myopathy diagnosis has improved our understanding of the clinical and genetic spectrum of different subtypes and their overlaps in Indian patients. This, in turn, will enhance the global gene-variant-disease databases by including data from developing countries/continents for more efficient clinically driven molecular diagnostics.

Clinico-Electrophysiological and Genetic Overlaps and Magnetic Resonance Imaging Findings in Charcot-Marie- Tooth Disease: A Pilot Study from Western India.

BACKGROUND: Charcot-Marie-Tooth (CMT) disease is clinically and genetically heterogeneous. There are no published series describing clinical, electrophysiological, and genetic information on CMT from the Indian subcontinent. Magnetic resonance imaging (MRI) neurography technique provides useful information about the plexus and roots and can be employed in patients with CMT. SETTINGS AND DESIGN: A prospective, observational study carried out at a tertiary care hospital in Western India. SUBJECTS AND METHODS: CMT patients fulfilling the UK Genetic Testing Network criteria were included. They underwent clinical, electrophysiological, radiological, and multigene panel testing. RESULTS: Totally 22 patients (19 males, 3 females; 18 sporadic and 4 familial cases) were studied. Pes cavus (19), hammer toes (16), and scoliosis was seen in 1 patient. Electrophysiology revealed motor predominant neuropathy with 15 demyelinating (10 uniform and 5 multifocal) and 7 axonal patterns. Thickened lumbosacral plexuses on MRI neurography were evident in 6/10 studied patients, all 6 having demyelinating neuropathy. Genetic analysis identified PMP22, GJB1, SH3TC2, HSPB1, SPTLC2, MPZ, AARS, and NEFH gene mutations. CONCLUSIONS: This small series documents the pattern of CMT neuropathies as seen in Western India. Clinico-electrophysiological and genetic diagnosis showed general concordance some overlaps and reiterated advantages of gene panel testing in this heterogeneous group of neuropathies. MRI neurography was useful as an additional investigation to detect nerve enlargement in patients with demyelinating neuropathies.

Acute Ischemic Stroke Treatment Using Mechanical Thrombectomy: A Study of 137 Patients.

BACKGROUND: Mechanical thrombectomy (MT) is the most effective treatment in large vessel occlusion (LVO). We have analyzed our initial experience of MT of 137 patients in anterior circulation (AC) and posterior circulation (PC) LVO using Solitaire stent retriever device. METHODS: Retrospective cohort analysis of 112 AC and 25 PC acute ischemic strokes was done considering various baseline characteristics, risk factors, National Institute of Health Stroke Scale (NIHSS) change, revascularization rate, complications, and functional outcome at 3 months using modified Rankin score. RESULTS: Out of 137 patients, occlusion was found in M1 segment (44.5%), carotid T occlusion (37.2%), and basilar artery (18.2%). Atrial fibrillation was important risk factor for Carotid T occlusion. 50.4% patients received intravenous thrombolysis. Baseline mean NIHSS in AC was 15.5 (±4.32), and PC was 19 (±5.5). Tandem lesions were noted in 14.6%. There was significant difference in mean door-to-needle time for AC and PC (220 ± 80.6 and 326 ± 191.8 min, respectively). Mean time to revascularization for AC (39.5 ± 14.1) and PC (42.2 ± 19.4) was similar. Procedural success (modified thrombolysis in cerebral infarction ≥2b) observed in AC and PC was 92.9% and 84%, respectively (P = 0.154). NIHSS at admission between 5 and 15 and immediate postprocedure NIHSS improvement >4 was associated with significant better clinical outcome at 3 months. Overall complication rate was about 15.3% including symptomatic intracranial hemorrhage in 8.1% and 6.6% deaths. CONCLUSION: MT is safe treatment and equally effective for both AC and PC LVO. With careful patient selection, clinical outcome in PC was comparable to AC despite delayed presentation and higher baseline NIHSS.