Genetic association between atopy and behavioral symptoms in middle childhood.

The relationship of atopic and behavioral symptoms in a community sample of 66 monozygotic and 141 dizygotic twin pairs, ages 4-11 years, was investigated via mother report questionnaires. Within-person correlation between atopic symptoms and Child Behavior Checklist internalizing symptoms (CBCL-INT) was .21 (p < .001) for the total sample. Cross-correlations between atopy and CBCL-INT were .26 for monozygotic and .04 for dizygotic twins. A common and specific factor model applied to the data revealed that the cross-correlation between atopy and CBCL-INT was mainly due to genetic influences (77% of the covariance). This study supports the hypothesis that there is a shared genetic risk for atopy and internalizing symptoms.