Bethlem肌病(BM)是一种由VI型胶原基因突变引起的疾病。它是一种轻度进行性疾病,其特征是近端肌肉无力和手指挛缩,手腕,肘部,还有脚踝.BM是主要由显性COL6A1、COL6A2或COL6A3突变引起的常染色体显性遗传。然而,还报道了一些伴有双侧面部无力和Beevor征的胶原VI突变病例。这项研究介绍了一名50岁的女性患者,其症状始于童年时期,并且随着年龄的增长,该疾病的进展缓慢。在30岁的时候,患者表现为不对称的近端肌无力,神经系统检查显示双侧面部无力和Beevor阳性体征。磷酸肌酸激酶略有升高,肌电图显示肌病改变,下肢肌肉的磁共振成像(MRI)显示肌肉MRI与VI型胶原(COL6)相关肌病(COL6-RM)相关。全基因组测序技术鉴定出COL6A3基因中的杂合突变c.6817-2(IVS27)A>G,这本身就是一种新的突变。本研究报告了另一例BM,这是由隐性COL6A3内含子变异引起的,拓宽BM的临床谱和遗传异质性。
Bethlem myopathy (BM) is a disease that is caused by mutations in the collagen VI genes. It is a mildly progressive disease characterized by proximal muscle weakness and contracture of the fingers, the wrist, the elbow, and the ankle. BM is an autosomal dominant inheritance that is mainly caused by dominant COL6A1, COL6A2, or COL6A3 mutations. However, a few cases of collagen VI mutations with bilateral facial weakness and Beevor\'s sign have also been reported. This study presents a 50-year-old female patient with symptoms of facial weakness beginning in childhood and with the slow progression of the disease with age. At the age of 30 years, the patient presented with asymmetrical proximal muscle weakness, and the neurological examination revealed bilateral facial weakness and a positive Beevor\'s sign. Phosphocreatine kinase was slightly elevated with electromyography showing myopathic changes and magnetic resonance imaging (MRI) of the lower limb muscles showing the muscle MRI associated with collagen VI (COL6)-related myopathy (COL6-RM). The whole-genome sequencing technology identified the heterozygous mutation c.6817-2(IVS27)A>G in the COL6A3 gene, which was in itself a novel mutation. The present study
reports yet another
case of BM, which is caused by the recessive COL6A3 intron variation, widening the clinical spectrum and genetic heterogeneity of BM.