Genetics in primary headaches.

This tutorial describes different methods and results of genetic studies of primary headaches. A positive family history is imprecise, because it does not specify the number of affected, family size or relation to the proband. Nor does it include an interview of the possibly affected family members. Calculation of the familial aggregation after confirmation of the diagnosis by a physician is more precise. Compared to the general population, first-degree relatives of probands with migraine without aura, migraine with aura, chronic tension-type headache and cluster headache has a significantly increased risk of the proband's disorder. These data are confirmed in twin studies. The primary headaches are caused by a combination of genetic and environmental factors. A major breakthrough was identification of 3 different genes all causing the rare autosomal dominant inherited familial hemiplegic migraine. The genes encode ion channels. So far no genes have been identified to cause the more common types of primary headaches.