Familial hypoalphalipoproteinemia

Rare genetic disorders, including Tangier disease and LCAT (lecithin cholesterol acyltransferase) deficiency, are associated with extremely low levels of HDL. Familial hypoalphalipoproteinemia is a more common disorder with levels of HDL cholesterol usually below 35 mg/dL in men and 45 mg/dL in women. These patients tend to have premature atherosclerosis, and the low HDL may be the only identified risk factor. Management should include special attention to avoidance or treatment of other risk factors. Niacin increases HDL in many of these patients. Reductase inhibitors and fibric acid derivatives exert lesser effects. 

Familial hypoalphalipoproteinemia (rare) in which the serum concentration of (protective) HDL is low. Coronary heart and peripheral vascular disease result. 

This disorder is characterized by normal plasma hpids and LDL cholesterol and reduced HDL cholesterol, below the 5th percentUc. Although patients with this disorder are clinically normal, they have a high incidence of CHD. The molecular basis of familial hypoalphalipoproteinemia is unknown. This disorder is the result of either the decreased biosynthesis or the increased catabolism of HDL or apo A-L Although the mode of transmission is not certain, in some kindreds familial hypoalphalipoproteinemia is inherited as an autosomal dominant trait. 

In homozygous familial hypoalphalipoproteinemia, only traces of HDL cholesterol are found in plasma, and apo A-I is undetectable. These patients have corneal clouding and are at increased risk for development of premature CHD. Heterozygotes exhibit no clinical signs but have about... 

Familial hypoalphalipoproteinemia has been identified in several kindreds with a history of accelerated coronary disease. Plasma lipid and lipoprotein values were all normal except for reduced levels of HDL cholesterol (50% of... 

ABCAl Cholesterol, PC Familial hypoalphalipoproteinemia, Tangier disease... 

Familial hypoalphalipoproteinemia A deficiency in HDL due to mutations at the ABCAl locus. 

Tangier disease is a rare recessive disorder in which patients have almost no HDL. Cholesterol ester accumulates in macrophages and macrophage-rich tissues like spleen and liver. Familial hypoalphalipoproteinemia (FHA) is a very common dominant disorder in which people have low HDL (typically <30 mg/dl) and suffer from premature heart disease even without an elevation in LDL. 

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