Extracellular matrix remodeling genes polymorphisms and risk of chronic bronchitis and recurrent pneumonia in children.

We investigated the association of matrix metalloproteinases, the disintegrin and metalloprotease 33 and the tissue and serum inhibitors of proteinase gene polymorphisms with severe chronic respiratory diseases in Tatar children. We analyzed the case-control data sample from a total of 592 Tatar individuals, consisting of 119 children with chronic bronchitis, 138 with recurrent pneumonia and 335 control children residing in Ufa (Russia). The percentage of heterozygous genotype for the MMP9 (2660A>G) was higher among healthy children (52.