Plasma apolipoprotein concentrations in familial apolipoprotein A-I and A-II deficiency (Tangier disease)

Familial apolipoprotein A-I and A-II deficiency (Tangier disease) is characterized by cholesterol ester deposition in histiocytes, decreased plasma cholesterol and low density lipoprotein cholesterol (C-LDL), and a striking deficiency of high density lipoproteins (HDL). We measured plasma lipid, lipoprotein cholesterol, and plasma apolipoprotein (apo) A-I, A-II, B, C-I, C-II, C-III, D, and E concentrations in 7 Tangier homozygotes, 2 obligate heterozygotes, and 50 normal subjects. Heterozygotes had modest reductions in high density lipoprotein cholesterol (C-HDL), plasma apoA-I, and apoA-II levels. Mean concentrations (+/- SD) of plasma C-HDL and apolipoproteins A-I, A-II, B, C-I, C-II, C-III, D, and E in mg% in normals were: 50 +/- 14, 134 +/- 24, 68 +/- 18, 98 +/- 20, 7 +/- 2, 3.7 +/- 2, 13 +/- 5, 10 +/- 4, and 10 +/- 4, respectively; and in homozygotes were: 1 +/- 1, 1.3 +/- 0.7, 4.8 +/- 2.5, 82.6 +/- 18, 4.1 +/- 1.7, 2.3 +/- 0.9, 6.5 +/- 3.8, 2.2 +/- 0.5, +/- 3.1, respectively. Homozygotes had C-HDL, apoA-I and apoA-II levels which were 2%, 1%, and 7% (p less than .001) of normal, respectively, and mean levels of apolipoproteins B, C-I, C-II, C-III, D, and E which were 84%, 59%, 62%, 50%, 22%, and 54% of normal, respectively. There was heterogeneity of these latter apolipoprotein concentrations among homozygotes. Mean apoC-I, apoC-III, apoD, and apoE levels were significantly less than normal (pp less than .05) in homozygotes. These data indicate that homozygotes have variable but generally decreased apoC and apoE levels, a deficiency of apoD, and a striking reduction in plasma apoA-I and apoA-II concentrations.