Identification of a shared, common haplotype segregating with an SGCB c.544 T > G mutation in Indian patients affected with sarcoglycanopathy.

Sarcoglycanopathy is the most frequent form of autosomal recessive limb-girdle muscular dystrophies caused by mutations in SGCB gene encoding beta-sarcoglycan proteins. In this study, we describe a shared, common haplotype co-segregating in 14 sarcoglycanopathy cases from 13 unrelated families from south Indian region with the likely pathogenic homozygous mutation c.544 T > G (p.Thr182Pro) in SGCB. Haplotype was reconstructed based on 10 polymorphic markers surrounding the c.544 T > G mutation in the cases and related family members as well as 150 unrelated controls from Indian populations using PLINK1.9. We identified haplotype H1 = G, A, G, T, G, G, A, C, T, G, T at a significantly higher frequency in cases compared to related controls and unrelated control Indian population. Upon segregation analysis within the family pedigrees, H1 is observed to co-segregate with c.544 T > G in a homozygous state in all the pedigrees of cases except one indicating a probable event of founder effect. Furthermore, Identical-by-descent and inbreeding coefficient analysis revealed relatedness among 33 new pairs of seemingly unrelated individuals from sarcoglycanopathy cohort and a higher proportion of homozygous markers, thereby indicating common ancestry. Since all these patients are from the south Indian region, we suggest this region to be a primary target of mutation screening in patients diagnosed with sarcoglycanopathy.

Lived Experience of Spouses of Persons with Motor Neuron Disease: Preliminary Findings through Interpretative Phenomenological Analysis.

INTRODUCTION: Motor neuron disease (MND) is a progressive neuromuscular disorder that can have significant and debilitating impact on the affected patient and families. Spouses are the primary carers for persons with MND in India, and the life of the person with MND and their spouse is never the same after the diagnosis. AIM: The objective was to explore the lived experience of spouses of persons diagnosed with MND. METHODS: A qualitative exploratory study with three-point interviews was conducted with spouse caregivers of two persons diagnosed with MND who were receiving treatment from a national tertiary referral care center for neurological disorders. All the patients were diagnosed as definite MND according to the modified El Escorial criteria. With the spouses, in-depth interviews were conducted at their home, lasting on an average of 1 hour using a semi-structured interview guide (prompts). Interpretative phenomenological analysis was used to derive themes from the interviews. RESULTS: The major themes emerged from the analysis were meaning of MND which contained the subthemes of delay in diagnosis and deterioration, psychological response across illness trajectory, relationship with the subthemes of changing roles in being acarer, marital relationship, to be seen as doing "right," and communication; adaptation with the subthemes of coping strategies and support system and life without the loved one. CONCLUSION: The changes in the lives of spouses and in strategies for caring the partner with deterioration of symptoms in the illness trajectory are explained in this study. The palliative approach in the management of MND has to take into account, the experiences and needs of carers since care happens at home.

Congenital myasthenic syndrome with mild intellectual disability caused by a recurrent SLC25A1 variant.

Congenital myasthenic syndromes (CMS) are a clinically and genetically heterogeneous group of disorders caused by mutations which lead to impaired neuromuscular transmission. SLC25A1 encodes a mitochondrial citrate carrier, associated mainly with the severe neurometabolic disease combined D-2- and L-2-hydroxyglutaric aciduria (D/L-2-HGA). We previously reported a single family with a homozygous missense variant in SLC25A1 with a phenotype restricted to relatively mild CMS with intellectual disability, but to date no additional cases of this CMS subtype had been reported. Here, we performed whole exome sequencing (WES) in three additional and unrelated families presenting with CMS and mild intellectual disability to identify the underlying causative gene. The WES analysis revealed the presence of a homozygous c.740G>A; p.(Arg247Gln) missense SLC25A1 variant, the same SLC25A1 variant as identified in the original family with this phenotype. Electron microscopy of muscle from two cases revealed enlarged and accumulated mitochondria. Haplotype analysis performed in two unrelated families suggested that this variant is a result of recurrent mutation and not a founder effect. This suggests that p.(Arg247Gln) is associated with a relatively mild CMS phenotype with subtle mitochondrial abnormalities, while other variants in this gene cause more severe neurometabolic disease. In conclusion, the p.(Arg247Gln) SLC25A1 variant should be considered in patients presenting with a presynaptic CMS phenotype, particularly with accompanying intellectual disability.

Anti-AChR, MuSK, and LRP4 antibodies coexistence: A rare and distinct subtype of myasthenia gravis from Indian subcontinent.

BACKGROUND: Myasthenia gravis is B-cell mediated autoimmune disease and is associated with antibodies against the acetylcholine receptor (AChR), muscle-specific kinase (MuSK) and lipoprotein-related protein 4 (LRP4) in the postsynaptic membrane at the neuromuscular junction. There are few studies on the concurrent presence of two positive antibodies in the sera of patients with myasthenia gravis. CASE DESCRIPTION: A 32-year male admitted to the hospital with progressive neuromuscular weakness. He was diagnosed with Myasthenia gravis disorder mimicking Amyotrophic Lateral Sclerosis. We herein report a rare co-existence of three antibodies (anti-AChR, MuSK, and LRP4 antibodies) in the patient's serum. CONCLUSION: We present a detailed clinical and laboratory analysis of the patient. This case report will emphasize the importance of evaluating anti-MuSK and anti-LRP4 antibodies even in patients with anti-AChR antibodies.