Abetalipoproteinemia

Abetalipoproteinemia is caused by changes (mutations) in the MTTP gene. The MTTP gene gives the body instructions to make a protein needed for creating beta-lipoproteins. These lipoproteins are necessary for the body to absorb fats, cholesterol, and fat-soluble vitamins (vitamins A, D, E and K), and for transporting these substances in the blood. Mutations in the MTTP result in a lack of beta-lipoproteins, leading to an inability to absorb and transport these substances. This in turn leads to the nutritional and neurologic problems in affected people.

The Genetic Testing Registry (GTR) provides information about the genetic tests available for abetalipoproteinemia. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Prenatal testing may be available for pregnancies at increased risk if the mutations in the family have been identified.

Abetalipoproteinemia is inherited in an autosomal recessive manner. This means that to be affected, a person must have a mutation in both copies of the responsible gene in each cell. Affected people inherit one mutated copy of the gene from each parent, who is referred to as a carrier. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When 2 carriers of an autosomal recessive condition have children, each child has a:

• 25% (1 in 4) chance to be affected
• 50% (1 in 2) chance to be an unaffected carrier like each parent
• 25% chance to be unaffected and not be a carrier

The following organizations are focused on helping individuals and families touched by a rare disease.

Global Genes is a leading rare disease patient advocacy group whose mission is the "eliminate the challenges of rare Disease". They have toolkits to help individuals and families become advocates and share their story.
Rare Toolkits

Some of the many titles include:

How to Promote Your Rare Disease Through Social Media
Using Storytelling to Raise Awareness for Your Rare Disease
So You Think You Want to Start a Nonprofit

Global Genes also offers informative procasts that you may find of interest. One example is "Helping Patients with the Same Undiagnosed Condition Find Each Other".
RARECast (Podcasts)

Global Genes
World Headquarters
28 Argonaut, Suite 150
Aliso Viejo, CA 92656
Telephone: 959-248-RARE (7273)
E-mail: contact@globalgenes.org
Website: https://globalgenes.org

The National Organization for Rare Disorders (NORD) is a federation of voluntary health organizations helping people with rare diseases through programs of education, advocacy, research, and patient service. NORD has information on connecting with others at the following link:
http://rarediseases.org/for-patients-and-families/

National Organization for Rare Disorders (NORD)
55 Kenosia Avenue
PO Box 1968
Danbury, CT 06813-1968
Toll-free: 1-800-999-6673 (voicemail only)
Telephone: 203-744-0100
TDD: 203-797-9590
Fax: 203-798-2291
E-mail: orphan@rarediseases.org
Website: https://www.rarediseases.org

RareConnect is an online resource where rare disease patients and families can develop communities and conversations across the world. The project is a joint collaboration between EURORDIS (European Rare Disease Organisation) and NORD (National Organization for Rare Disorders).
https://www.rareconnect.org/en

Facebook is another way to connect with others through online communities.

GenomeConnect is a patient portal, or registry, that is working to build the knowledge base about genetics and health that will allow researchers and doctors to study the impact of genetic variation on health conditions. This group recently announced that interested participants may now connect with one another to find others with a similar diagnosis. Visit the following link to learn more about this resource.
https://www.genomeconnect.org/

Abetalipoproteinemia is a condition characterized by the inability to fully absorb dietary fats, cholesterol and fat-soluble vitamins. Signs and symptoms appear in the first few months of life and can include failure to thrive; diarrhea; acanthocytosis; and stool abnormalities. Other features develop later in childhood and often impair the function of the nervous system, potentially causing slower intellectual development; poor muscle coordination; progressive ataxia; and an eye disorder called retinitis pigmentosa. Most of the symptoms are due to defects in the absorption and transport of vitamin E. Abetalipoproteinemia is caused by mutations in the MTTP gene and is inherited in an autosomal recessive manner. Early diagnosis, high-dose vitamin E therapy, and medium-chain fatty acid supplements may slow the progression of the nervous system abnormalities. Long-term outlook is reasonably good for most affected people who are diagnosed early. If left untreated, the condition can result in early death.

With advanced planning and appropriate testing, it may be possible to find out if a fetus or child will be affected.

If the genetic changes (mutations) in an affected family member have been identified, prenatal genetic testing may be possible during pregnancy. Genetic testing may be performed on a sample obtained by chorionic villus sampling (at about 10 to 12 weeks gestation), or by amniocentesis (usually performed at about 15 to 18 weeks gestation). If the condition is confirmed in the fetus by either method, planning for an affected child and/or pregnancy management options may be discussed with a health care provider.

As an alternative to prenatal diagnosis during the pregnancy, preimplantation genetic diagnosis (PGD) before a pregnancy may be an option if the mutations in the family are known. PGD is done after in vitro fertilization (IVF) to diagnose a genetic condition in an embryo before it is introduced into the uterus. When having PGD, only embryos known to be unaffected are introduced into the uterus for a possible pregnancy.

People interested in genetic testing, prenatal diagnosis, and/or PGD should speak with a genetic counselor or other genetics professional regarding their testing options. A genetics professional can help by:

• thoroughly evaluating the family history
• addressing questions and concerns
• assessing recurrence risks
• facilitating genetic testing if desired
• discussing reproductive options

The long-term outlook (prognosis) is reasonably good for most people who are diagnosed and treated early. However, how well each person does depends on the amount of brain and nervous system problems. Therefore, the prognosis can vary. People with prolonged vitamin deficiency, especially of vitamin E, may develop very limiting ataxia and gait disturbances. Some people may develop retinal degeneration and blindness.

A nutritionist or other qualified medical professional should be consulted for specific dietary instruction in people with abetalipoproteinemia. Treatment involves very large doses of vitamin E, as well as large doses of vitamin supplements containing other fat-soluble vitamins (vitamin A, vitamin D, and vitamin K). Linoleic acid supplements are also recommended.

Several diet changes and/or restrictions are also needed to prevent stomach problems. A low-fat diet may help with digestive symptoms; medium chain triglycerides may be used (under supervision of a specialist) as a source of fat in the diet.

Management in adults typically focuses on specific complications associated with the disorder, and depends on the signs and symptoms present. Affected people may need consultations with several other types of specialists, including a lipidologist, gastroenterologist, hepatologist, ophthalmologist, and neurologist.