Chylomicron retention disease

A rare genetic disorder affecting lipid metabolism

Classification
External resources

Chylomicron retention disease (CRD), also known as Anderson's disease, is a rare autosomal recessive disorder that affects the body's ability to absorb and transport dietary lipids. This condition is characterized by the improper formation and secretion of chylomicrons, which are lipoprotein particles responsible for the transport of dietary triglycerides, cholesterol, and fat-soluble vitamins from the intestine to other parts of the body.

Pathophysiology

Chylomicron retention disease is caused by mutations in the SAR1B gene, which encodes a protein involved in the transport of chylomicrons from the endoplasmic reticulum to the Golgi apparatus within enterocytes. This defect leads to the accumulation of chylomicrons in the enterocytes, preventing their release into the lymphatic system and subsequently into the bloodstream. As a result, individuals with CRD have low levels of circulating chylomicrons and lipoproteins, leading to hypocholesterolemia and hypotriglyceridemia.

Clinical Features

Patients with chylomicron retention disease typically present in infancy or early childhood with symptoms related to malabsorption of dietary fats and fat-soluble vitamins. Common clinical features include:

• Steatorrhea (fatty stools)
• Failure to thrive
• Growth retardation
• Muscle weakness
• Neurological symptoms due to vitamin E deficiency, such as ataxia and peripheral neuropathy
• Retinitis pigmentosa

Diagnosis

The diagnosis of chylomicron retention disease is based on clinical presentation, laboratory findings, and genetic testing. Key diagnostic features include:

• Low levels of plasma triglycerides and cholesterol
• Low levels of fat-soluble vitamins, particularly vitamin E
• Genetic testing revealing mutations in the SAR1B gene

Management

Management of chylomicron retention disease focuses on dietary modifications and supplementation to address the malabsorption of fats and fat-soluble vitamins. Treatment strategies include:

• A low-fat diet to reduce the burden on the impaired lipid transport system
• Supplementation with fat-soluble vitamins, especially vitamin E, to prevent neurological complications
• Monitoring of growth and development in children

Prognosis

With appropriate dietary management and vitamin supplementation, individuals with chylomicron retention disease can lead relatively normal lives. However, early diagnosis and intervention are crucial to prevent irreversible complications, particularly those affecting the nervous system.

Related pages

• Lipid metabolism disorders
• Hypocholesterolemia
• Fat malabsorption
• Autosomal recessive disorders