Polymorphism in apolipoprotein(a) kringle IV 37 (Met/Thr): Frequency in a London population and its association with coronary artery disease

Abstract

Background: A raised concentration of lipoprotein(a) [Lp(a)] in human plasma has been considered as a risk factor for coronary artery disease (CAD). Apolipoprotein(a) and plasminogen genes are exceptionally similar to a variable number of plasminogen-like kringle IV repeats in the apo(a) gene. Polymorphisms have been previously identified in the apolipoprotein(a) kringle IV 37. Hypothesis: In order to determine the frequency of the apolipoprotein(a) kringle IV 37 Met66 → Thr polymorphism in a London- based population and to assess the relationship of this polymorphism with CAD in Caucasian patients, we geno-typed two groups of people of different ethnic origin (Caucasian and Afro-Caribbean) for the mutation using standard polymerase chain reaction (PCR) techniques. Methods: The first group consisted of 182 unrelated Caucasian patients (107 men and 75 women, mean age 59.7 ± 10.2 years) recruited at St. George's Hospital. They were defined as patients with 0, 1 or ≤ 2 vessel disease patients depending on the degree of stenosis in none, one, or several major epicardial arteries. The second group comprised 64 unrelated patients of Afro-Caribbean origin attending a hypertension clinic at St. George's Hospital. Results: It was shown that the prevalence of the Met55→Thr mutation is markedly higher in Caucasians than in Afro-Caribbeans and that this mutation is not associated with either Lp(a) levels or severity of CAD.