chylomicron retention disease

Chylomicron retention disease is a familial condition characterized by impaired lipid absorption, leading to malnutrition and multiple organ complications. It results from mutations in the SAR1B gene, which disrupts the proper transport of chylomicrons in intestinal cells. Affected individuals often present in infancy or early childhood with symptoms such as failure to thrive, diarrhea, and nutrient deficiencies. The condition is very rare, affecting fewer than one in a million people.

The clinical features of chylomicron retention disease include constant diarrhea and hypocholesterolemia, which are considered hallmark signs of the condition. Many affected individuals also experience fat malabsorption and steatorrhea, leading to nutritional deficiencies and failure to thrive. Over time, complications such as elevated liver enzymes, retinopathy, and growth delay may emerge, while less frequently, vomiting, abdominal distension, and myopathic changes on EMG have been observed. Not all individuals experience all features, and severity varies considerably.

Chylomicron retention disease is caused by mutations in the SAR1B gene, which plays a crucial role in the cellular transport of chylomicrons within intestinal cells. The condition is inherited in an autosomal recessive pattern, meaning that affected individuals inherit two copies of the mutation, one from each parent. This condition is more common when parents share a common ancestor, as both carriers are more likely to harbor the same rare genetic variant. Genetic counseling is recommended for families to understand the recurrence risk and implications for family planning.

Currently, management focuses on supportive care and symptom control since there are no specific foundational therapies or FDA-approved treatments available for chylomicron retention disease. Treatment is tailored to the individual and typically involves a multidisciplinary team to address nutritional deficiencies, gastrointestinal symptoms, and complications affecting the liver, neurological, and ophthalmologic systems. Regular surveillance is an essential part of long-term care, helping to detect potential complications early. Patients should discuss treatment options with their healthcare team, and genetic counseling is recommended to help guide family planning decisions.

Outcomes for individuals with chylomicron retention disease vary depending on symptom severity, age at diagnosis, and access to specialized care. With current standards of care, many individuals manage their symptoms into adulthood, although complications related to malabsorption and organ involvement can occur over time. The clinical course is variable, with some individuals experiencing stabilization after initial challenges while others may face ongoing issues; outcomes described in medical literature continue to evolve as standards of care improve. Families often find it helpful to connect with specialists familiar with this condition and to seek genetic counseling for additional support and guidance.