The familial hyperchylomicronemia syndrome: new insights into underlying genetic defects

Article Abstract:

A review is presented of the clinical features, origin and diagnosis, and treatment of the familial hyperchylomicronemia syndrome. This is a rare genetic disease in which blood levels of triglycerides (one form in which fats are stored and transported) and chylomicrons (large fatty complexes that enter the blood after a meal) increase dramatically (hypertriglyceridemia and hyperchylomicronemia). Patients with this condition often develop abdominal pain and inflammation of the pancreas (pancreatitis) early in childhood; the symptoms are especially severe after a fatty meal. The concentration of chylomicrons gets so high that the particles are ingested by skin macrophages (scavenger cells), forming small yellow lesions on the buttocks, arms, and legs. Other signs are described. Patients with this syndrome do not seem to develop atherosclerosis (deposition of fatty plaque on the walls of blood vessels), but are in danger as a result of pancreatic damage. Two substances are deficient in the familial hyperchylomicronemia syndrome: lipoprotein lipase (LPL), which normally removes chylomicrons from the circulation; and apolipoprotein C-II (apo C-II), a protein that helps break down triglycerides. When either of these proteins is absent, the blood plasma appears milky (fatty) even when the patient has fasted. A review is presented of the families with apo C-II deficiencies that have been investigated; known mutations of the apo C-II and LPL genes, and their physiologic consequences, are described. LPL deficiency is more common than deficiency of apo C-II, and the genetic defects underlying it are more varied. Patients with familial hyperchylomicronemia are treated by dietary restriction: no more than 15 percent of their total calories should be taken in as fat. Both saturated and unsaturated fat should be reduced. Supplementation with medium-chain triglyceride oil can be provided if patients need more fat calories. A case history is presented, for illustrative purposes, of a five-year-old boy with the familial hyperchylomicronemia syndrome. (Consumer Summary produced by Reliance Medical Information, Inc.)

Care and treatment, Case studies, Genetic aspects, Hyperlipidemia

---

Lipoprotein(a): clinical approach to a unique atherogenic lipoprotein

Article Abstract:

Individuals with high blood concentrations of lipoprotein(a) (Lp(a)) may have higher risk of coronary artery disease (CAD) than those who have lower concentrations. Lp(a) is a substance that transports fat in the blood. Several studies have found that patients with CAD have higher blood concentrations of Lp(a). Plaque deposits taken from the blood vessels of CAD patients contain large amounts of Lp(a). Part of Lp(a) is similar in structure to plasminogen, an enzyme involved in breaking up blood clots, and may interfere with the break-up of blood clots. Heredity may determine the amount of Lp(a) in an individual's blood, but other factors can effect Lp(a) levels. Individuals with certain genetic disorders and metabolic diseases may have higher levels of Lp(a). Different immunological tests can determine blood levels of Lp(a). Individuals with high Lp(a) who do not have CAD may not need to lower their blood concentration of Lp(a). Aerobic exercise and the drug nicotinic acid may help lower Lp(a) levels in CAD patients.

Health aspects, Causes of, Coronary heart disease, Lipoprotein A

---

Abetalipoproteinemia: new insights into lipoprotein assembly and vitamin E metabolism from a rare genetic disease

Article Abstract:

A 30-year-old woman was diagnosed with abetalipoproteinemia (ABL). ABL is a rare genetic disorder characterized by the absence of certain blood lipoproteins, degeneration of retinal pigments, malformed red blood cells, malabsorption and neuromuscular abnormalities. Her symptoms included malabsorption of fat, incoordination, visual impairment and low blood levels of cholesterol. Her parents were fourth cousins, and three of her sisters had milder symptoms similar to hers. Laboratory tests revealed that she had ABL. Progression of the disease slowed after she started fat-soluble vitamin therapy. ABL may be caused by a deficiency of microsomal transfer protein. This protein may play an important role in the assembly and secretion of lipoproteins. ABL is also characterized by abnormalities in vitamin E metabolism. Patients with ABL should take vitamin E supplements.

Vitamin E, Lipoproteins, Abetalipoproteinemia

Similar abstracts:

• Abstracts: DNA discoverer James Watson now dreams of curing genetic diseases. A few words of advice from a woman of letters - Ann Landers
• Abstracts: Slow glucose removal rate and hyperinsulinemia precede the development of type II diabetes in the offspring of diabetic patients
• Abstracts: Cyclosporine. Risk factors for cyclosporine-induced nephropathy in patients with autoimmune diseases. Systemic treatment of severe psoriasis: the role of cyclosporine
• Abstracts: Mixed connective tissue disease, overlap syndromes, and eosinophilic fasciitis. Eosinophilic fasciitis associated with L-tryptophan ingestion
• Abstracts: Steroid hormone abnormalities in women with severe idiopathic constipation. DNA probes for diagnosis of intestinal infection

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.