A unique pattern of apo(a) polymorphism in an isolated east Greenlandic Inuit (Eskimo) population.

Abstract

Eskimos of the east coast of Greenland very rarely had contacts with Caucasians until late in the 19th century. Their genes are therefore likely to be similar to those in the original Eskimo gene pool. We have compared serum concentrations of Lp(a) and apo(a) phenotypes in 78 East Greenland Eskimos (EGE) with those in Eskimos from Western Greenland (WGE) (n = 100) and Caucasian Danes (n = 466). Lp(a) levels were higher in EGE (median: 11.9 mg/dl [95% CI: 9.1-16.4]) than in Danes (p < 0.01), (median: 6.3 mg/dl [95% CI: 5.5-7.3]) and WGE (p < 0.01), (median: 7.8 mg/dl [95% CI: 5.7-10.2]). Lp(a) concentrations above 30 mg/dl were (p < 0.05) more common in EGE (19%) than in WGE (9%) and similar (p = 0.89) to those in Danes (20%). Apo(a) molecules as small as S2 or smaller (S1, B and F) were present in 26% of Danes and in 3% of WGE but were absent in EGE (p < 0.01). In contrast, a large apo(a) variant (VS4) was present in 54% of EGE and 62% of WGE, whereas it was very rare in Danes (2%). Lp(a) concentrations were inversely associated with apo(a) size in EGE (p < 0.05), WGE (p < 0.01) and Danes (p < 0.01), but EGE with S3 or S4 had significantly higher Lp(a) levels than Danes (p < 0.05) with the same phenotypes.