Medical Care
Abetalipoproteinemia (ABL) and familial hypobetalipoproteinemia (FHBL) are rare genetic disorders. Infants and children who present with homozygous FHBL or ABL require early treatment with very high doses of vitamin E. Management in adults includes treatment of the complications of the disorders.
To prevent the neurologic manifestations that occasionally occur with FHBL, heterozygous patients receive modest supplementation with vitamin E.
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Severe restriction of long-chain fatty acids to 15 g per day is recommended to improve the complications of fat malabsorption.
In infants with failure to thrive, brief supplementation with medium-chain triglycerides may be necessary, but the amount must be closely monitored to avoid liver toxicity.
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Vitamin supplementation [5]
Very large doses of oral vitamin E (100-300 mg/kg/d) are used to raise the tissue vitamin E concentration and to prevent neurologic complications in homozygotes.
Heterozygotes with FHBL should receive modest doses of vitamin E to prevent the development of neurologic complications.
Vitamin A (10,000-25,000 IU/d) supplementation is instituted if an elevated prothrombin time suggests vitamin K depletion.
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Symptomatic treatment and treatment of complications
Consultations
Patients who present with advanced complications of abetalipoproteinemia (ABL) or familial hypobetalipoproteinemia (FHBL), as well as the patients' first-degree relatives, require a comprehensive evaluation for the diagnosis and management of these conditions and for genetic counseling. [5] Expertise from the following consultants may be needed:
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Lipidologist - Patients with ABL or FHBL may require an extensive and time-consuming assessment, including genetic studies and chromosomal analyses. A lipidologist at a major center specializing in the disorders of lipid metabolism is the most appropriate consultant to involve from the start.
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Gastroenterologist - In patients with malabsorption syndrome, a thorough assessment by a gastroenterologist is necessary to exclude the many other common causes of this condition.
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Hepatologist - Patients presenting with transaminase elevation and hepatic enlargement may require specialized evaluation by a liver specialist.
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Ophthalmologist - Patients require assessment of any visual disturbance by an ophthalmologist. They also may need monitoring and periodic follow-up assessments for the development of retinal degeneration.
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Neurologist - A complete neurologic evaluation is necessary in each patient. Patients, particularly those who present with gait disturbances or ataxia, need a thorough evaluation and subsequent monitoring of any spinocerebellar degeneration.
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Nutritionist - A nutritionist must carefully evaluate the diets of patients with ABL or FHBL and suggest appropriate modifications. [22]
Diet and Activity
Diet
A low-fat diet, especially a reduction in the intake of long-chain fatty acids to less than 15 g per day, may alleviate intestinal symptoms. [22]
Oral supplementation of fat-soluble vitamins (ie, A, D, E, K) is needed.
Supplementation of vitamin E (alpha tocopherol in high doses) may prevent progression and may even reverse some of the stigmata of spinocerebellar degeneration. However, no randomized or case-controlled study is available to support this intervention.
Activity
No particular restriction in activity is recommended. Patients should be as active as dictated by their general health.
In patients with spinocerebellar degeneration or ataxia, only well-tolerated and supervised activity should be advised. Such patients may benefit from orthotic devices.
