Genetic predisposition
Genetic predisposition is a major factor in the aetiology of AR. The clinical evidence include: the fact that a family history of allergic rhinitis is often present and the association of Allergic rhinitis with other atopic diseases that possess a genetic basis, such as allergic asthma or atopic dermatitis.
It has been reported that Allergic Rhinitis has a hereditary component but does not exhibit a Mendelian hereditary pattern. The evidence has been demonstrated by studies in twins. It has been reported that in monozygous twins, a 45 - 60% concordance for AR was observed, while this concordance drops to 25% in dizygous twins [reviewed in 4]. Based on such studies, it has been estimated