Familial visceral myopathy

Familial visceral myopathy (FVM), also known as hereditary hollow visceral myopathy or familial intestinal pseudo-obstruction, is a rare inherited disorder affecting the smooth muscle of hollow internal organs, particularly the gastrointestinal tract and sometimes the urinary tract. The condition is caused by degeneration and fibrosis of the smooth muscle layers in the walls of the intestines and other hollow viscera, leading to impaired motility and functional obstruction without any physical blockage being present. Patients typically present with chronic intestinal pseudo-obstruction, characterized by recurrent episodes of abdominal distension, pain, nausea, vomiting, and constipation that mimic mechanical bowel obstruction. The esophagus, stomach, small intestine, colon, and urinary bladder may all be affected. Megaduodenum, megacystis (enlarged bladder), and gastroparesis are commonly observed. Malnutrition and weight loss frequently develop due to impaired nutrient absorption and feeding difficulties. The severity and age of onset can vary considerably, even within the same family, ranging from neonatal presentations to adult-onset disease. Both autosomal dominant and autosomal recessive forms have been described. Mutations in the ACTG2 gene (encoding smooth muscle gamma-2 actin) are a well-recognized cause of the autosomal dominant form. Treatment is primarily supportive and symptomatic, including nutritional support (which may require total parenteral nutrition), prokinetic agents to stimulate gut motility, management of bacterial overgrowth with antibiotics, and surgical interventions such as decompressive procedures. In severe cases, intestinal transplantation may be considered. There is currently no curative therapy available.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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