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Megacystis microcolon intestinal hypoperistalsis syndrome

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Other Names:
MMIH syndrome; Berdon syndrome; MMIHS; MMIH syndrome; Berdon syndrome; MMIHS; Megacystis-microcolon-intestinal hypoperistalsis-hydronephrosis syndrome See More
Categories:
This disease is grouped under:
Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) 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 changes (mutations) in the ACTG2 gene and is inherited in an autosomal dominant manner. However medical scientists believe that many cases of MMIHS are caused by de novo mutations in the ACTG2 gene (meaning the mutation in the gene happened by mistake during the making of the sperm or egg). There is currently no cure for MMIHS and treatment is supportive. In the majority of patients total parenteral nutrition is required.[1]
Last updated: 10/20/2016
Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is primarily characterized by abdominal distention caused by an enlarged bladder (megacystis) and intestinal pseudo-obstruction.The enlarged bladder may be detected prenatally.[2] Children with MMIHS may have various abnormalities of the digestive tract, including microcolon (very small colon), malrotation of the gut, decreased or absent intestinal movements, and short bowel. Additional abnormalities of the urinary tract that have been described include renal dysplasia, hydronephrosis, and enlargement of the ureter. Abnormalities that have been reported in some cases include undescended testes or bilateral streak gonads (underdeveloped gonads), heart anomalies, umbilical hernia, or omphalocele.[2]
Last updated: 8/10/2017

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 28 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Abdominal distention
Abdominal bloating
Abdominal swelling
Belly bloating
Bloating
[ more ] 		0003270
Hypoperistalsis 0100771
Megacystis 0000021
Microcolon 0004388
Nausea and vomiting 0002017
30%-79% of people have these symptoms
Hydroureter 0000072
Intestinal malrotation 0002566
Multicystic kidney dysplasia 0000003
Polyhydramnios
High levels of amniotic fluid
0001561
5%-29% of people have these symptoms
Cryptorchidism
Undescended testes
Undescended testis
[ more ] 		0000028
Death in infancy
Infantile death
Lethal in infancy
[ more ] 		0001522
Neoplasm of the heart
Heart tumor
0100544
Omphalocele 0001539
Pancreatitis
Pancreatic inflammation
0001733
Sepsis
Infection in blood stream
0100806
Umbilical hernia 0001537
Percent of people who have these symptoms is not available through HPO
Abdominal pain
Pain in stomach
Stomach pain
[ more ] 		0002027
Aganglionic megacolon
Enlarged colon lacking nerve cells
0002251
Autosomal dominant inheritance 0000006
Constipation 0002019
Diarrhea
Watery stool
0002014
Dysphagia
Poor swallowing
Swallowing difficulties
Swallowing difficulty
[ more ] 		0002015
Hydronephrosis 0000126
Intestinal pseudo-obstruction 0004389
Malnutrition 0004395
Urinary retention 0000016
Vesicoureteral reflux 0000076
Vomiting
Throwing up
0002013
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Last updated: 7/1/2020
This condition is part of a group of disorders caused by mutations in the ACTG2 gene. ACTG2-related disorders are inherited in an autosomal dominant manner.[1]
Last updated: 8/19/2015
Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is inherited in an autosomal dominant manner.[1] This means that having a change (mutation) in only one copy of the responsible gene in each cell is enough to cause features of the condition. There is nothing that either parent can do, before or during a pregnancy, to cause a child to have this condition.

In some cases, an affected person inherits the mutation from an affected parent. In other cases, the mutation occurs for the first time in a person with no family history of the condition. This is called a de novo mutation. While the exact proportion of inherited versus de novo mutations is unknown, current data suggest that de novo mutations are common.[1]

When a person with a mutation that causes an autosomal dominant condition has children, each child has a 50% (1 in 2) chance to inherit that mutation. However, the severity of signs and symptoms can vary within a family. If the mutation in a family member with MMIHS has been identified, prenatal testing for pregnancies at increased risk is possible.[1]
Last updated: 8/10/2017

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
Survival in MMIHS seems to have improved, thanks to more specialized care, innovations in parenteral nutrition, and introduction of multivisceral transplantation.[2] Long-term survival usually requires total parenteral nutrition and urinary catheterization or diversion. Most long-term survivors have ileostomies.[1] In families with an inherited MMIHS-causing mutation, some family members with a mutation have milder features, living into adolescence and early adulthood.[1]

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.[2]
Last updated: 8/10/2017

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
This disorder should not be mistaken for a milder and autosomal dominant disorder, called chronic idiopathic intestinal pseudo-obstruction, in which megacystis is also present, or for prune belly syndrome (see these terms).
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • The Centers for Mendelian Genomics program is working to discover the causes of rare genetic disorders. For more information about applying to the research study, please visit their website.
  • The U.S. National Institutes of Health, through the National Library of Medicine, developed ClinicalTrials.gov to provide patients, family members, and members of the public with current information on clinical research studies. There is a study titled Pediatric Patients With Metabolic or Other Genetic Disorders which may be of interest to you.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Megacystis microcolon intestinal hypoperistalsis syndrome. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • How long can a person live if they are born with megacystis microcolon intestinal hypoperistalsis syndrome? See answer


  1. Wangler MF. ACTG2-Related Disorders. GeneReviews. June 11, 2015; http://www.ncbi.nlm.nih.gov/books/NBK299311/.
  2. Puri P. Megacystis-microcolon-intestinal hypoperistalsis syndrome. Orphanet. September, 2012; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=2241.