Abetalipoproteinemia

Definition

Bassen-Kornzweig syndrome is a rare, inherited disease in which a person is unable to fully absorb dietary fats through the intestines.

Alternative Names

Causes

Bassen-Kornzweig syndrome is an autosomal recessive condition that more often affects males, but can also affect girls. It is caused by a defect in the microsomal triglyceride transfer protein (MTP) gene.

The defect makes the body unable to create lipoproteins (molecules of fat combined with protein). Persons with this condition are unable to properly digest fat and essential vitamins.

Symptoms

• Balance and coordination difficulties
• Curvature of spine
• Decreased vision that gets worse over time
• Developmental delay
• Failure to thrive (grow) in infancy
• Muscle weakness
• Poor muscle coordination that usually develops after age 10
• Protruding abdomen
• Slurred speech
• Stool abnormalities, including:
  • Fatty stools that appear pale in color
  • Frothy stools
  • Abnormally foul-smelling stools

Exams and Tests

Tests that may be done to help diagnose this condition include:

• Apolipoprotein B blood test
• Blood tests to look for vitamin deficiencies (fat-soluble vitamins A, D, E, and K)
• Complete blood count (CBC)
• Cholesterol studies
• Electromyography
• Eye exam
• Nerve conduction velocity
• Stool sample analysis

Genetic testing may be available for mutations in the MTP gene.

Treatment

Consult a nutritionist or other medical professional for dietary instruction. Large doses of vitamin supplements containing the fat-soluble vitamins (vitamin A, vitamin D, vitamin E and vitamin K) are given. Linoleic acid supplements are also recommended.

To avoid intestinal symptoms, persons with this syndrome should not eat long-chain triglycerides and limit fat intake to 5 - 20 grams per day. The diet should contain no more than 5 daily ounces of lean meat, fish, or poultry. Use skim milk instead of whole milk.

Since a certain amount of fat is needed for normal growth and development in all people, medium chain triglycerides are alternatively used as the major source of fat in the diet. These are absorbed from the gut differently than other fats, and thus avoid the intestinal symptoms. Medium chain triglycerides are taken as a dietary supplement, typically under the supervision of a doctor or nutritionist. They should be used with caution because they may cause liver damage.

Outlook (Prognosis)

The outcome is related to the degree and progression of neurological and visual problems. Severe forms of the disease lead to irreversible neurologic disease before age 30.

Possible Complications

• Blindness
• Mental deterioration
• Loss of function of peripheral nerves, ataxia

When to Contact a Medical Professional

Call if your infant or child exhibits symptoms of this disease.

Prevention

High doses of fat soluble vitamins may be able to slow progression of some problems such as degeneration of the retina and decreased vision.

Rodriguez-Oquendo A, Kwiterovich Jr PO. Dyslipidemias. In: Fernandes J, Saudubray J-M, van den Berghe G, Walter JH, eds. Inborn metabolic diseases: diagnosis and treatment. Germany: Springer; 2006:400-401.