Getting to grips with genetic twists

MR A was very careful with his food and ate only fish and vegetables for his meals. He exercised regularly in the belief that exercise would raise the high density lipoprotein cholesterol (HDL-C) or "good" cholesterol, and protect him from heart disease. His low density lipoprotein cholesterol (LDL-C) or "bad" cholesterol was mildly elevated. Hence, he was surprised to learn that he had a severe narrowing of one of his major heart arteries. While this may seem rather unusual, advances in genetic studies are helping us to understand this better.

Although 99.5 per cent of humans' DNA sequence in their chromosomes is identical, it is the 0.5 per cent that is not that makes one individual so different from another.

Advances in genetic studies have enabled physicians to identify heart disorders related to abnormalities in single genes affecting heart muscles (for example, arrhythmogenic right ventricular dysplasia, hypertrophic cardiomyopathy and dilated cardiomyopathy), heart rhythms (long QT syndrome, Brugada syndrome, atrial fibrillation, Wolff-Parkinson-White syndrome), and cholesterol (familial hypercholesterolemia).