We tested for association between four linkage disequilibrium (LD)-tagging SNPs (rs2243123, rs2243151, rs668998, and rs17826053) in IL12A and asthma and allergy-related (serum total and allergen-specific IgE, and skin test reactivity [STR] to two common allergens) phenotypes in two samples: 417 Costa Rican children with asthma and their parents, and 470 families of 503 white children in the Childhood Asthma Management Program (CAMP). Here, IGHE is linked to Allergy.