Bassen-Kornzweig syndrome

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

Abetalipoproteinemia; Acanthocytosis; Apolipoprotein B deficiency

Causes, incidence, and risk factors

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

Signs and tests

There may be damage to the retina of the eye (retinitis pigmentosa).

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. Vitamin E especially helps to restore lipoproteins. Linoleic acid supplements are also recommended.

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

Because everyone needs a certain amount of fat for normal growth and development, medium-chain triglycerides are alternatively used as the major source of fat in the diet. Because these fats are absorbed from the gut differently than other fats, they can help patients avoid 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.

Expectations (prognosis)

The outcome depends on the degree and progression of brain/nervous system (neurological) and visual problems. Severe forms of the disease lead to irreversible neurologic disease before age 30.

Complications

• Blindness
• Mental deterioration
• Loss of function of peripheral nerves, uncoordinated movement (ataxia)

Calling your health care provider

Call your health care provider if your infant or child has symptoms of this disease. Genetic counseling can help families understand the condition and the risks of inheriting it, and learn how to care for the patient.

Prevention

High doses of fat-soluble vitamins may slow the progression of some problems, such as retina damage and decreased vision.

References

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.