A study on 300 asthmatic children, 300 controls and their parents confirms the genetic transmission of allergy and asthma.

BACKGROUND Several studies have shown the role of genetic factors in allergies, and ascertained that atopic diseases are transmitted by parents, especially by mothers. MATERIALS AND METHODS In order to explore the genetic risk of a child with a family history (FH) of allergy, we have enrolled into this prospective study 300 children, 173 males and 127 females, aged 3.5 to 7.5 years (median age 4.4 years), that included: family (FH) and personal history skin prick tests (SPTs) and specific IgE (RAST), who attended the Pediatric Allergy and Immunology Division of Rome University because affected with respiratory allergy We have studied the FH of these children asking whether their parents and brothers/sisters had atopic diseases, and detailing whether such diseases were respiratory or food allergies (FA). The parents of all children gave their informed consent. We analyzed data using the X2 method. RESULTS One hundred and twentyseven parents were atopic (42.3%), in addition to 20 brothers/sisters. In detail 90.2% of fathers, 84% of mothers and 65% of brothers/sisters had asthma or allergic rhinitis (AR). Very less parents had urticaria, especially the mothers and brothers/sisters suffered with atopic dermatitis (AD), and some mothers with FA. In 23 children from these parents most had AD and respiratory allergy. In 300 children comparable for age and sex with no respiratory illness recruited from our out-patient clinic 40 parents, 14 mothers and 26 fathers and 9 brothers/sisters had asthma or AR (p = 0.0001), some fathers had also urticaria and two brothers AD. CONCLUSION A relevant part of respiratory allergy is not transmitted by mothers. Our prospective study stresses that 42.3% of parents are atopic, and FH of their children was positive for respiratory allergy in 82-92% of cases. Thus respiratory allergy can have an autosomal dominant mode of inheritance, but considering the other atopic diseases, the transmission can be polygenic. The impact of genetic factors in these children is emphasized by the high part of asthmatic brothers/sisters.