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

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 Met 66 →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 Met 66 →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.