Why is it that around 20% of people in Western societies are significantly affected by
acne, and other people are not? The biggest factor is almost certainly genetic. But could there be more to it?
It has been acknowledged for years that if you have a first-degree relative (parent or sibling) with acne, then you have a much higher chance of suffering from it yourself. You share 50% of your genes with a first-degree relative, and most estimates are that if one or more is affected by acne, then you will have roughly a one in two chance of getting it yourself. An even better way of looking at the genetic contribution to acne is to investigate monozygotic (identical) twins.
A large study in Australia calculated that 80% of the likelihood of suffering from acne could be attributed to one gene, with the other 20% attributable to environmental factors.