Abetalipoproteinemia is a rare inherited condition characterized by the body’s inability to absorb the cholesterol, fats and fat-soluble vitamins present in the food.
Initial symptoms may occur within the first few month of the individual’s life that can progress into other neurological abnormalities. In most cases, the symptoms are associated with the abnormalities of vitamin E absorption and transportation. The early diagnosis and supplement therapy can slow the progress of nervous system problems. Although the outlook for affected individuals appears good if diagnosed early, but if untreated, it can result in death. It is estimated that around less than 1 in 1,000,000 people are affected with abetalipoproteinemia.
Causes
This is caused by the mutation in the gene MTTP which delivers instructions for the production of a protein responsible for creating beta-lipoproteins. This protein is essential for the transportation and absorption of fats, cholesterol and fat-soluble vitamins in the body. The mutated gene results in the absence of beta-lipoproteins thus affecting the body’s absorption of these essential materials. As a result, nutritional deficiency occurs featuring the symptoms of abetalipoproteinemia. This condition is inherited in an autosomal recessive manner where both the copies of the gene, one from each parent, are defective.
Symptoms
The symptoms of abetalipoproteinemia initially appear within the first few months of the patient’s life. These affected infants often are presented with poor weight gain and growth rate. Abetalipoproteinemia tends to affect different parts of the body including the eyes, gastrointestinal tract, the blood and causes various neurological problems. Some of the symptoms that occur with the poor fat absorption include diarrhea, swelling of the abdomen and foul smelling stools. These affected individuals also develop neurological complications associated with vitamin E deficiency between the age of 2 and 20. This can include problems with coordinating voluntary movements, difficulty speaking, tremors, muscle weakness and developmental delays. In some cases, the skeletal abnormalities include curvature of the spine and clubfoot. The muscle imbalance can develop making them unable to stand properly or walk unaided. Some of the affected individuals may develop problems with their eyes that create night blindness, loss of peripheral vision, tunnel vision and loss of color vision. They also have malformed red blood cells in a condition known as acanthocytosis that can cause anemia.
Diagnosis
Diagnosis is based on identifying the features associated with this disorder and in the evaluation of the patient’s history. Additional tests may include blood tests to detect low levels of cholesterol, triglycerides and lipid-soluble vitamins. The abnormal red blood cells can also be detected in the blood analysis. A neurological assessment, an endoscopy, ultrasound scan, eye examination can all assist in the evaluation process to diagnose this condition.
Treatment
The affected individuals may require the coordinated efforts of different specialists such as a neurologist, gastroenterologist and ophthalmologist. Neurological and eye examination should be conducted regularly to identify deterioration. A specific dietary plan is required for the individuals affected with abetalipoproteinemia. Usually, the treatment includes taking large doses of vitamin E and supplements that contains other fat-soluble vitamins. It is important to accommodate a diet that is low in fat in order to assist with the digestive symptoms.