Berdon syndrome

Overview

Berdon syndrome, also known as Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome (MMIHS), is a rare and often fatal congenital disorder that affects the gastrointestinal and urinary systems. It is primarily characterized by an enlarged bladder (megacystis), underdeveloped colon (microcolon), and severely reduced intestinal movement (hypoperistalsis). This condition is typically identified in newborns and can result in significant feeding and urinary difficulties. Berdon syndrome predominantly affects females and is considered a form of visceral myopathy, where the smooth muscle of internal organs does not function properly.

Causes

Berdon syndrome is most often caused by genetic mutations that affect the development and function of smooth muscle tissue in the gastrointestinal and urinary tracts. The most commonly implicated genes include:

• ACTG2 – encoding smooth muscle actin, mutations here are linked to autosomal dominant inheritance forms

• MYH11, LMOD1, and MYLK – less frequently associated but also implicated in smooth muscle dysfunction

Inheritance patterns may be autosomal recessive or autosomal dominant, depending on the specific mutation. Sporadic cases due to de novo mutations have also been reported.

Symptoms

Symptoms of Berdon syndrome usually appear at birth or shortly thereafter and may include:

• Massively distended bladder causing abdominal swelling

• Severe constipation or absence of bowel movements due to intestinal hypoperistalsis

• Microcolon detected via imaging

• Feeding intolerance, vomiting, and abdominal distension

• Urinary retention requiring catheterization or surgical intervention

• Failure to thrive and poor weight gain

In many cases, these symptoms lead to early clinical evaluation and diagnosis.

Diagnosis

The diagnosis of Berdon syndrome involves a combination of clinical evaluation, imaging studies, and genetic testing. Key diagnostic steps include:

• Abdominal ultrasound – to identify bladder enlargement and assess urinary tract anatomy

• Contrast enema or X-rays – to reveal microcolon and reduced intestinal motility

• Biopsy of intestinal or bladder wall – showing smooth muscle abnormalities such as vacuolization or disorganization

• Genetic testing – to confirm mutations in ACTG2 or other relevant genes

Early diagnosis is critical to planning supportive care and potential interventions.

Treatment

There is no cure for Berdon syndrome. Management is focused on supportive care and improving quality of life. Treatment options include:

• Total parenteral nutrition (TPN) – since the intestines often cannot absorb nutrients adequately

• Urinary diversion procedures – such as vesicostomy or catheterization to manage urinary retention

• Surgical interventions – including colostomy or ileostomy to bypass non-functioning bowel segments

• Organ transplantation – in selected cases, multivisceral or intestinal transplantation may be considered

• Infection prevention – due to the high risk of sepsis related to TPN and urinary tract infections

• Multidisciplinary care – involving neonatologists, surgeons, nephrologists, gastroenterologists, and nutrition specialists

Prognosis

The prognosis for Berdon syndrome is generally poor, particularly in the neonatal period. Many infants with the condition do not survive beyond the first year of life due to complications from malnutrition, infection, or organ failure. However, with advances in neonatal intensive care, long-term parenteral nutrition, and organ transplantation, a small number of children have survived into childhood and even adolescence. Prognosis largely depends on the severity of visceral dysfunction and access to specialized medical care.