MMIH Syndrome; Berdon Syndrome; MMIHS; Megacystis Microcolon Intestinal Hypoperistalsis Hydronephrosis Syndrome; Megacystis Microcolon Hypoperistalsis Syndrome

Megacystis Microcolon Intestinal Hypoperistalsis Syndrome (MMIH) is a rare congenital condition characterized by abdominal distension caused by a largely dilated non-obstructed urinary bladder (megacystis); very small colon (microcolon); and decreased or absent intestinal movements (intestinal peristalsis). Usual clinical presentation is similar to other neonatal intestinal obstructions: bile stained vomiting and failure to pass meconium (the first bowel movement the baby has). Other intestinal anomalies may be present like intestinal malrotation. Many problems with the urinary tract result from the bladder dysfunction. It is part of a group of conditions caused by mutations in the ACTG2 gene, and is inherited in an autosomal dominant manner. However, medical scientists believe that many cases of MMIH are caused by spontaneous mutations in the ACTG2 gene.

Diagnostic testing: Genetic testing documenting mutation(s) in the ACTG2 gene confirms the diagnosis.

Imaging Studies and Physical Examination Findings for MMIH show various congenital abnormalities of the digestive tract, including:

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  Microcolon (very small colon);

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  Malrotation of the gut;

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  Decreased or absent intestinal movements;

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  Short bowel;

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  Abnormalities of the urinary tract including renal dysplasia;

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  Hydronephrosis;

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  Enlargement of the ureter;

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  Undescended testes or bilateral streak gonads (underdeveloped gonads);

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  Heart anomalies;

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  Umbilical hernia; or

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  Omphalocele.

ICD-9: 751.5

Long-term survival usually requires total parenteral nutrition and urinary catheterization or diversion. Most long-term survivors have ileostomies. In families with an inherited MMIH-causing mutation, some family members with a mutation have milder features, living into adolescence and early adulthood. While there are reports of longer survival, the prognosis and life expectancy remains poor, and it is still fatal in many cases. The main causes of death include sepsis, malnutrition, or multiple organ failure.

There is currently no cure for MMIH. Treatment is supportive. Multi-visceral organ transplantation may be considered.

SUGGESTED PROGRAMMATIC ASSESSMENT*

Suggested MER for Evaluation:

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  Clinical history and examination that describes the diagnostic features of the impairment;

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  Imaging study results (X-ray, MRI, CT scan); and

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  Genetic testing confirming diagnosis of the impairment.

Suggested Listings for Evaluation:

REMARKS