CERVO Brain Research Center, 2601 Chemin de la Canardière, Quebec, Quebec G1J 2G3, Canada; Université Laval, Québec, Canada; CHU de Québec, Hôpital de l'Enfant-Jésus, Département des sciences neurologiques, Quebec, Quebec, Canada.
Centre régional de Rimouski, Département de neurologie, Quebec, Quebec, Canada.
Neuromuscul Disord. 2020 Aug;30(8):669-673. doi: 10.1016/j.nmd.2020.05.009. Epub 2020 Jun 6.
The spinal muscular atrophies (SMA) affect lower motor neurons leading to important muscle atrophy and paralysis. Some cases of SMA affect mostly the lower limbs and are called autosomal dominant spinal muscular atrophy, lower extremity predominant (SMALED). So far, two genes have been identified to cause this phenotype, DYNC1H1 (SMALED1) and BICD2 (SMALED2). This pathology is rare, but patients exhibit classical features which should be recognised by physicians. We present two unrelated cases of SMALED2 with previously described c.320C>T BICD2 mutations. Our cases exhibit non-progressive weakness and atrophy of the lower limbs associated with contractures and unique muscle MRI findings suggestive of classical SMALED2. We also performed an extensive review of the literature to present the classical and atypical phenotypes of BICD2. Indeed, some features appear to be highly suggestive of the disease, including upper limb sparing, sparing of the adductors muscles on physical examination and MRI, congenital contractures and normal nerve conductions studies.
脊髓性肌萎缩症（SMA）影响下运动神经元，导致重要的肌肉萎缩和瘫痪。一些 SMA 病例主要影响下肢，称为常染色体显性遗传脊髓性肌萎缩症，下肢为主（SMALED）。到目前为止，已经确定了两个基因导致这种表型，DYNC1H1（SMALED1）和 BICD2（SMALED2）。这种病理很少见，但患者表现出经典特征，医生应该识别这些特征。我们报告了两例先前描述的 BICD2 c.320C>T 突变引起的 SMALED2 不相关病例。我们的病例表现为下肢进行性无力和萎缩，伴有挛缩和独特的肌肉 MRI 发现，提示为经典的 SMALED2。我们还对文献进行了广泛的回顾，以呈现 BICD2 的典型和非典型表型。事实上，一些特征似乎高度提示该病，包括上肢保留、体检和 MRI 上的内收肌保留、先天性挛缩和正常神经传导研究。
