2例不同遗传方式中央轴空病的临床、病理、影像及基因分析

目的分析2例不同遗传方式中央轴空病患者的临床、肌肉影像学、病理学及基因突变特点,比较其临床表型和分子遗传学的异同点。方法详细收集2例患者的临床资料、肌肉MRI及病理学,靶向捕获二代测序进行基因检测,Sanger测序验证及家系共分离分析。结果 2例分别为常染色体隐性(autosomal recessive,AR)和显性(autosomal dominant,AD)患者,表现儿童早期起病,四肢近端无力伴萎缩,面肌受累;双下肢肌肉MRI见广泛肌肉萎缩及脂肪浸润,股直肌回避;病理氧化酶染色见肌纤维典型的轴空结构,AR型存在偏心轴空;发现斯里兰卡肉桂碱受体1(Ryanodine receptor 1,RYR1)基因的3个错义突变,其中一个未报道。结论本研究的2例经典型患者存在不同遗传方式,在临床表型、受累肌群分布及病理存在诸多异同,可能与RYR1基因的不同突变形式相关,靶向二代测序可以提高确诊率。

Clinical,pathological, imaging and genetic analysis of two cases of central core disease with different inheritance modes

Objective To study the clinical, pathological, imaging features of two cases of central core disease (CCD) with different inheritance and to explore the similarities and differences between autosomal recessive CCD (AR-CCD) and autosomal dominant CCD (AD-CCD). Methods Clinical manifestations, family history, muscle MRI and muscle biopsy were collected. Targeted next generation sequencing (NGS) and sanger sequencing were applied for genetic analysis. Co-segregation analysis was further conducted in one family. Results Their common clinical manifestations included childhood early-onset proximal limbs muscle weakness and dystrophy accompanied with facial involvement. The MRI revealed extensive muscular dystrophy and fatty filtration in the both thighs, but not in rectus femoris. Pathology of skeletal muscle showed typical central cores in type Ⅰ muscle fibers and eccentric cores only in AR-CCD. Targeted NGS identified 3 missense mutations in RYR1, including one novel mutation. Conclusion The present study has described clinical and pathological features of two typical CCD patients with different inheritance, which may be associated with the different mutations in RYR1 gene. Targeted NGS apparently improves the genetic diagnosis of CCD.