Objective: Immunocharacterization of congenital muscular dystrophy (CMD) to determine the frequency of various subtypes in a large Indian Cohort. Materials and Methods: This retrospective (2014-2017) study was carried on muscle biopsies of clinically suspected cases of CMD with histological evidence of dystrophy/myopathic features. Immunohistochemistry (IHC) to antibodies against laminin (α2, α5,β1,γ1), Collagen-VI (A1,2,3), and Western blot (WB) for α-dystroglycan and POMT1 was performed. Results: The study included 57 cases, of which 15 cases (26.3%) had mean age at presentation of 3.5 years, M: F = 1.5:1, elevated creatinine kinase (CK) (mean 1657 U/L), global developmental delay, multiple contractures, abnormal facies, white matter hyperintensities and showed laminin-α2 deficiency (Merosin deficient CMD). In addition, secondary reduction in laminin-β1, over-expression of laminin-α5, and preserved laminin-γ1 was noted. Ullrich CMD constituted 11/57 cases (19.2%) with mean age at presentation of 5.3 years, M: F = 1.2:1 and normal CK. They presented with proximal muscle weakness, soft velvety palms and soles, contractures, and joint hyperextensibility. Collagen-VI (A1,2,3) showed either complete (n = 3) or sarcolemmal specific (n = 8) loss of staining. Out of the remaining 31 cases, WB for α-dystroglycan was performed in 17 cases which showed deficiency in seven (12.3%). Three of these in addition revealed secondary partial loss of laminin-α2. WB for POMT1 showed deficiency in a single case clinically diagnosed Walker–Warburg syndrome, who presented with seizures and classical features of pachygyria, lissencephaly, and cerebellar cyst on MRI. Twenty-four cases (42.2%) remained uncharacterized and need genetic evaluation. Conclusion: The study helped in characterizing 57.8% of the proband. Immunotyping helps to direct mutational analysis for targeted genes and offers a potential route for prenatal diagnosis.


中文翻译：

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免疫组织化学和蛋白质印迹在分析临床疑似先天性肌营养不良病例中的效用


目的：先天性肌营养不良症 (CMD) 的免疫表征，以确定大型印度队列中各种亚型的频率。材料和方法：这项回顾性（2014-2017 年）研究对临床疑似 CMD 病例的肌肉活检进行，具有营养不良/肌病特征的组织学证据。进行了针对层粘连蛋白 (α2、α5、β1、γ1)、胶原蛋白-VI (A1、2、3) 的抗体的免疫组织化学 (IHC)，以及针对 α-肌营养不良蛋白和 POMT1 的蛋白质印迹 (WB)。结果：该研究包括 57 例病例，其中 15 例 (26.3%) 的平均年龄为 3.5 岁，M: F = 1.5:1，肌酐激酶 (CK) 升高（平均 1657 U/L），全球发育迟缓，多发性挛缩、面容异常、白质高信号并表现出层粘连蛋白-α2 缺乏症（Merosin deficient CMD）。此外，注意到层粘连蛋白-β1 的二次减少、层粘连蛋白-α5 的过度表达和保留的层粘连蛋白-γ1。Ullrich CMD 占 11/57 例 (19.2%)，平均年龄为 5.3 岁，M: F = 1.2:1，CK 正常。他们出现近端肌肉无力、柔软柔软的手掌和脚底、挛缩和关节过度伸展。胶原蛋白-VI (A1,2,3) 显示完整 ( n = 3) 或肌膜特异性 ( n= 8) 染色损失。在其余 31 例中，17 例进行了 α-肌营养不良蛋白的 WB，其中 7 例（12.3%）显示缺乏。其中三个还显示层粘连蛋白-α2 的继发性部分损失。POMT1 的 WB 显示在临床诊断为 Walker-Warburg 综合征的单个病例中存在缺陷，该病例在 MRI 上表现为癫痫发作和典型的厚脑回、无脑回畸形和小脑囊肿的特征。24 例 (42.2%) 仍未确定特征，需要进行基因评估。结论：该研究有助于表征 57.8% 的先证者。免疫分型有助于指导目标基因的突变分析，并为产前诊断提供潜在途径。