Severe gastric distension in a teenage boy

This is the authors' abstract. We don't add key points for this paper.

A 16‐year‐old male presented with acute abdominal pain, nausea, and distension and was found to have severe gastric dilation on imaging. Antroduodenal manometry showed erythromycin‐induced phase 3 migrating motor complex beginning in the antrum but post‐prandial antral hypoactivity. Mitochondrial DNA sequencing was normal. Exome analysis revealed a rare variant of uncertain significance in the smooth muscle myosin heavy chain 11 ( MYH11 ) gene (NM_002474.3: c.4123G>A, p.Asp1375Asn), which is necessary for smooth muscle contraction. Pathogenic MYH11 alterations cause multiple disorders, including autosomal dominant (AD) familial thoracic aortic aneurysm, AD visceral myopathy, and autosomal recessive megacystis‐microcolon‐intestinal‐hypoperistalsis syndrome. Amino acid p.Asp1375 is within the rod region of the MYH11 protein that self‐assembles to form thick filaments; thus, pathogenic variants in this region may affect filament formation and impair interactions with thin filaments. While the phenotype overlap is compelling, further research is needed to determine the clinical significance of this alteration.