Bowen–Conradi syndrome

Overview

Bowen–Conradi syndrome is a rare, inherited genetic disorder characterized by severe growth retardation, distinct facial features, and multiple skeletal and organ abnormalities. The condition is typically fatal in infancy, with most affected infants not surviving beyond the first year of life. Bowen–Conradi syndrome is especially prevalent in the Hutterite population of North America due to a higher carrier rate in this genetically isolated community. The syndrome is classified as a ribosomopathy, a disorder involving defective ribosome function that disrupts normal cell growth and development.

Causes

Bowen–Conradi syndrome is caused by a mutation in the EMG1 gene, which provides instructions for making a protein essential for proper ribosome assembly. The mutation impairs protein synthesis, leading to abnormalities in cell growth and division. The condition is inherited in an autosomal recessive pattern, meaning a child must inherit two defective copies of the gene—one from each parent—to be affected. Carriers, who have only one mutated gene, do not show symptoms but can pass the mutation to their offspring.

Symptoms

Signs and symptoms of Bowen–Conradi syndrome are usually apparent at birth or shortly thereafter. Common clinical features include:

• Severe intrauterine growth retardation (IUGR)

• Microcephaly – abnormally small head size

• Prominent nasal bridge and small jaw (micrognathia)

• Flexion contractures – stiff joints, particularly in the elbows and knees

• Rocker-bottom feet

• Feeding difficulties

• Respiratory problems – often due to underdeveloped lungs or chest abnormalities

• Genitourinary anomalies – including undescended testes or kidney abnormalities

• Delayed or absent developmental milestones

In some cases, hydrocephalus (accumulation of fluid in the brain) or brain malformations may also be present.

Diagnosis

Diagnosis of Bowen–Conradi syndrome is based on physical findings, family history, and genetic testing. Steps in the diagnostic process include:

• Clinical examination – recognizing characteristic facial features and physical anomalies

• Growth measurements – to assess prenatal and postnatal growth restriction

• Radiographic imaging – to identify skeletal abnormalities

• Genetic testing – confirming mutations in the EMG1 gene

• Carrier testing – available for individuals of Hutterite descent or others with a family history of the condition

Treatment

There is no cure for Bowen–Conradi syndrome, and treatment is supportive, aimed at managing symptoms and improving comfort. Interventions may include:

• Feeding support – including nasogastric or gastrostomy tube feeding for infants with poor oral intake

• Respiratory care – oxygen therapy or mechanical ventilation if needed

• Physical therapy – to manage joint contractures and improve comfort

• Palliative care – to provide comfort and support to the child and family, especially in severe cases

Due to the severity of the condition, aggressive interventions are often limited and focused on quality of life.

Prognosis

The prognosis for Bowen–Conradi syndrome is very poor. Most affected infants die within the first few months of life due to respiratory failure, severe malnutrition, or other complications. A few may survive longer with intensive medical support, but profound developmental and physical disabilities persist. Genetic counseling is highly recommended for families with a known history of the disorder, particularly in high-risk populations, to help assess carrier status and inform future reproductive decisions.