Clinical Guidance

Individuals with ACTG2 visceral myopathy can experience functional defects of smooth muscle involving both bladder and bowel. Bladder involvement can range from neonatal megacystis and megaureter (with its most extreme form of prune belly syndrome) at the more severe end to recurrent urinary tract infections and bladder dysfunction at the milder end. Intestinal involvement can range from malrotation, neonatal manifestations of microcolon, and megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) to chronic intestinal pseudoobstruction (CIPO) in neonates, infants, children, and adults. The clinical severity can range within a family; mildly affected family members may not be aware of the diagnosis. For example: • One individual (in a multi-generation Finnish family) with an ACTG2 pathogenic variant reported episodic mild abdominal pain but no surgery and no signs of visceral myopathy at age 19 years . • One individual diagnosed with "spastic colon" and irritable bowel syndrome had not required surgery or intervention in middle age . Table 2. ACTG2 Visceral Myopathy: Frequency of Select Features Feature | Percentage

Diagnostic Criteria

No consensus clinical diagnostic criteria for ACTG2 visceral myopathy have been published.

Suggestive Findings

ACTG2 visceral myopathy should be suspected in individuals with the following bladder and/or intestinal findings (which can range in a continuum from severe in neonates to more mild in older children and adults) and family history.

Bladder findings

Source: GeneReviews — "ACTG2 Visceral Myopathy"

Management Guidelines

No clinical practice guidelines for ACTG2 visceral myopathy have been published. The following recommendations are adapted from the Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome Overview.

Evaluations Following Initial Diagnosis

To establish the extent of disease and needs in an individual diagnosed with ACTG2 visceral myopathy, the evaluations summarized in this section (if not performed as part of the evaluation that led to the diagnosis) are recommended.

Surveillance Guidelines

Surveillance should be individualized using a multidisciplinary approach. Bladder and urinary tract comorbidities. Monitor voiding, urinary tract anatomy, and renal function. Intestinal manifestations. Monitor nutritional status and possible TPN-associated complications (line infections, liver disease) and consider need for multivisceral or isolated intestinal transplantation.

Source: GeneReviews — "ACTG2 Visceral Myopathy"