Ishigaki C, Patria S Y, Nishio H, Yabe M, Matsuo M
Division of Genetics, Kobe University School of Medicine, Japan.
Neurology. 1996 May;46(5):1347-50. doi: 10.1212/wnl.46.5.1347.
We report a Japanese Becker muscular dystrophy (BMD) patient with occasional myalgia and cramps during normal activity that developed at the age of 28 months. His family history was negative for neuromuscular diseases. Muscle biopsy analyses, including dystrophin immunostaining, disclosed no clinically relevant findings. The diagnosis of BMD was initially made at the age of 10 years, when indications of persistent high serum levels of CK prompted us to screen deletions in the dystrophin gene by amplification of 19 deletion-prone exons from the genomic DNA by the polymerase chain reaction (PCR). Among the exons examined, exons 13 and 17 were deleted. To clarify the size of the deletion, the dystrophin transcript was analyzed by reverse transcription PCR. The determined nucleotide sequence of the amplified product encompassing exons 10 to 20 disclosed that the entire segment corresponding to exons 13 to 18 (810 bp) was absent, a deletion that would be expected to cause the production of a dystrophin protein lacking 270 amino acids from the rod domain. This result indicates that occasional myalgia and cramps could be early clinical manifestations of mild BMD, especially in patients who have a deletion in the rod domain, and that deletion screening of the dystrophin gene might be the only reliable method to diagnose such cases.
我们报告了一名日本贝氏肌营养不良症（BMD）患者，该患者在28个月大时正常活动期间偶尔出现肌痛和抽筋。他的家族病史中无神经肌肉疾病。肌肉活检分析，包括抗肌萎缩蛋白免疫染色，未发现临床相关结果。BMD的诊断最初是在10岁时做出的，当时持续高血清肌酸激酶（CK）水平促使我们通过聚合酶链反应（PCR）从基因组DNA中扩增19个易缺失外显子来筛查抗肌萎缩蛋白基因的缺失。在所检测的外显子中，外显子13和17缺失。为了明确缺失的大小，通过逆转录PCR分析抗肌萎缩蛋白转录本。扩增产物涵盖外显子10至20的测定核苷酸序列显示，对应于外显子13至18（810 bp）的整个片段缺失，这种缺失预计会导致产生一种在杆状结构域缺少270个氨基酸的抗肌萎缩蛋白。这一结果表明，偶尔的肌痛和抽筋可能是轻度BMD的早期临床表现，尤其是在杆状结构域有缺失的患者中，并且抗肌萎缩蛋白基因的缺失筛查可能是诊断此类病例的唯一可靠方法。
