Abetalipoproteinemia Health Article

Diagnosis

The diagnosis of ABL is suspected from the intestinal, neuromuscular, and ocular symptoms, and is confirmed by laboratory tests showing acanthocytes in the blood and absence of betalipoproteins and chylomicrons in the blood. Other diseases resulting in similar intestinal or neurological symptoms, and those associated with symptoms related to malnutrition and vitamin deficiency must be excluded. As of 2000, there was no direct test of the MTP gene available for routine diagnostic testing. Accurate carrier testing and prenatal diagnosis are therefore not yet available. However, this could change at any time. Any couple whose child is diagnosed with ABL should be referred for genetic counseling to obtain the most up-to-date information.

Treatment and management

The recommended treatments for ABL include diet restrictions and vitamin supplementation. Reduced triglyceride content in the diet is suggested if intestinal symptoms require it. Large supplemental doses of vitamin E (tocopherol) have been shown to lessen or even reverse the neurological, muscular, and retinal symptoms in many cases. Supplementation with a water-soluble form of vitamin A is also suggested. Vitamin K therapy should be considered if blood clotting problems occur.

Occupational and physical therapy can assist with any muscular and skeletal problems that arise. Physicians that specialize in orthopedics, digestive disorders, and eye disease should be involved. Support groups and specialty clinics for individuals with multisystem disorders such as ABL are available in nearly all metropolitan areas.

Prognosis

ABL is rare, which means there have been few individuals on which to base prognostic information. The effectiveness of vitamin supplementation and diet restrictions will vary from person to person and family to family. Life span may be near normal with mild to moderate disability in some, but others may have more serious and even life-threatening complications. Arriving at the correct diagnosis as early as possible is important. However, this is often difficult in rare conditions such as ABL. Future therapies, if any, will likely focus on improving lipid absorption in the digestive tract. Further study of the MTP gene may lead to the availability of accurate carrier testing and prenatal diagnosis for some families.

ORGANIZATIONS

March of Dimes Birth Defects Foundation. 1275 Mamaroneck Ave., White Plains, NY 10605. (888) 663-4637. resourcecenter@modimes.org. <http://www.modimes.org>.

National Foundation for Jewish Genetic Diseases, Inc. 250 Park Ave., Suite 1000, New York, NY 10017. (212) 371-1030. <http://www.nfjgd.org>.

National Organization for Rare Disorders (NORD). PO Box 8923, New Fairfield, CT 06812-8923. (203) 746-6518 or (800) 999-6673. Fax: (203) 746-6481. <http://www.rarediseases.org>.

National Society of Genetic Counselors. 233 Canterbury Dr., Wallingford, PA 19086-6617. (610) 872-1192. <http://www.nsgc.org/GeneticCounselingYou.asp>.

National Tay-Sachs and Allied Diseases Association. 2001 Beacon St., Suite 204, Brighton, MA 02135. (800) 906-8723. ntasd-Boston@worldnet.att.net. <http://www.ntsad.org>.

Scott J. Polzin, MS, CGC