The study was renewed in FY 1999 and in FY 2004 to: further characterize asthma and closely related phenotypes; perform genetic modeling (complex segregation analysis) using one and two locus models as well as bivariate segregation analysis; complete the genome wide screen; fine map regions of interest and identify candidate genes, perform linkage disequilibrium and haplotype sharing analyses; and perform case control analysis of susceptibility and severity candidate genes for asthma.