Abstract：
BACKGROUND: Dominant gamma-smooth muscle actin gene (ACTG2) variants cause clinically diverse forms of visceral myopathy. Many patients undergo intestinal resection or biopsy before identification of their genetic defect. The pathology of ACTG2-variant visceral myopathy has not been evaluated systematically.
METHODS: Glass slides, ultrastructural images, molecular genetic reports, and clinical records from 16 patients with pathogenic (15) or likely pathogenic (1) ACTG2 variants were reviewed and compared with surgical specimens from controls (no evidence of a primary myopathy or pseudo-obstruction due to Hirschsprung disease) and published descriptions.
RESULTS: The variable clinical manifestations in our cohort matched those in the literature. Only non-specific light and electron microscopic findings observed in non-myopathic controls were encountered in 13 of 16 patients. The remaining 3 patients harbored hyalinized cytoplasmic inclusions in smooth muscle cells and 1 of them had polyglucosan bodies in the muscularis propria.
CONCLUSIONS: Apart from hyalinized inclusions, which were only observed in 3/16 patients, intestinal pathology in the majority of patients with ACTG2 variants is not indicative of an underlying visceral myopathy. Molecular testing should be considered even when no diagnostic intestinal pathology is identified.
METHODS: Glass slides, ultrastructural images, molecular genetic reports, and clinical records from 16 patients with pathogenic (15) or likely pathogenic (1) ACTG2 variants were reviewed and compared with surgical specimens from controls (no evidence of a primary myopathy or pseudo-obstruction due to Hirschsprung disease) and published descriptions.
RESULTS: The variable clinical manifestations in our cohort matched those in the literature. Only non-specific light and electron microscopic findings observed in non-myopathic controls were encountered in 13 of 16 patients. The remaining 3 patients harbored hyalinized cytoplasmic inclusions in smooth muscle cells and 1 of them had polyglucosan bodies in the muscularis propria.
CONCLUSIONS: Apart from hyalinized inclusions, which were only observed in 3/16 patients, intestinal pathology in the majority of patients with ACTG2 variants is not indicative of an underlying visceral myopathy. Molecular testing should be considered even when no diagnostic intestinal pathology is identified.
摘要：
背景：显性γ-平滑肌肌动蛋白基因（ACTG2）变异体可引起临床上不同形式的内脏肌病。许多患者在鉴定其遗传缺陷之前进行肠切除或活检。ACTG2变异型内脏肌病的病理学尚未得到系统评估。
方法：玻璃幻灯片，超微结构图像，分子遗传学报告，我们回顾了16例具有致病性(15例)或可能致病性(1例)ACTG2变异体的患者的临床记录,并将其与对照组(无原发性肌病或Hirschsprung病所致假性梗阻的证据)的手术标本进行了比较,并发表了相关描述.
结果：我们队列中不同的临床表现与文献中的一致。在16例患者中的13例仅遇到在非肌病对照中观察到的非特异性光镜和电子显微镜发现。其余3名患者在平滑肌细胞中含有透明的细胞质内含物，其中1名患者在固有肌层中具有聚葡聚糖体。
结论：除了透明夹杂物，仅在3/16患者中观察到，大多数ACTG2变体患者的肠道病理并不表明潜在的内脏肌病。即使没有确定诊断性肠道病理学，也应考虑进行分子检测。
方法：玻璃幻灯片，超微结构图像，分子遗传学报告，我们回顾了16例具有致病性(15例)或可能致病性(1例)ACTG2变异体的患者的临床记录,并将其与对照组(无原发性肌病或Hirschsprung病所致假性梗阻的证据)的手术标本进行了比较,并发表了相关描述.
结果：我们队列中不同的临床表现与文献中的一致。在16例患者中的13例仅遇到在非肌病对照中观察到的非特异性光镜和电子显微镜发现。其余3名患者在平滑肌细胞中含有透明的细胞质内含物，其中1名患者在固有肌层中具有聚葡聚糖体。
结论：除了透明夹杂物，仅在3/16患者中观察到，大多数ACTG2变体患者的肠道病理并不表明潜在的内脏肌病。即使没有确定诊断性肠道病理学，也应考虑进行分子检测。
