Chylomicron retention disease

Chylomicron retention disease (CRD), also known as Anderson disease or Anderson's disease, is a rare inherited disorder of lipid metabolism caused by mutations in the SAR1B gene. This gene encodes a protein essential for the transport of chylomicrons — large lipoprotein particles that carry dietary fats — from intestinal cells (enterocytes) into the lymphatic system and bloodstream. When this transport is impaired, fat accumulates within the enterocytes and fails to reach the circulation, leading to severe fat malabsorption. The disease primarily affects the gastrointestinal system and manifests in infancy or early childhood with chronic diarrhea, steatorrhea (fatty stools), failure to thrive, and abdominal distension. Because fat-soluble vitamins (A, D, E, and K) depend on chylomicron transport for absorption, patients develop deficiencies in these vitamins, which can lead to serious complications. Vitamin E deficiency, in particular, may cause progressive neurological problems including peripheral neuropathy, ataxia, and myopathy. Laboratory findings characteristically show very low levels of total cholesterol, LDL cholesterol, and apolipoprotein B in the blood, along with the absence of postprandial chylomicrons. Acanthocytosis (abnormally shaped red blood cells) may also be observed, and hepatic steatosis (fatty liver) can develop over time. Treatment is primarily supportive and focuses on dietary management with a low-fat diet supplemented with medium-chain triglycerides (MCTs), which can be absorbed directly into the portal circulation without requiring chylomicron formation. High-dose supplementation of fat-soluble vitamins, particularly vitamin E, is critical to prevent or slow neurological deterioration. With early diagnosis and appropriate management, the prognosis can be improved, though long-term monitoring for growth, nutritional status, and neurological function is essential. CRD belongs to a group of disorders known as hypobetalipoproteinemias and should be distinguished from abetalipoproteinemia, which has overlapping but distinct features.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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