<i>ACTG2</i> -Related Visceral Myopathy: Case Reports with Phenotypic Variations and Review of the Previously Published Cases

<b>Background:</b> <i>ACTG2</i> (smooth muscle actin γ-2) is a gene associated with smooth muscle function. <b>Introduction:</b> Variants in this gene can lead to visceral myopathy (VM), which is a spectrum of various disorders affecting smooth muscle in different parts of the body. There is gap in the literature regarding understanding the full scope of <i>ACTG2</i>-related VM. <b>Patients and methods:</b> Here we present the clinical and molecular investigation of three patients with visceral smooth muscle diseases carrying pathogenetic variants in the <i>ACTG2</i> gene. <b>Discussion and conclusion:</b> The severity of the disease varies in great extent, even among monochorionic twins sharing same mutation and intrauterine environment, suggesting that second-site factors are likely to impact disease manifestations.