The identification of the genes for cystic fibrosis (cystic fibrosis transmembrane conductance regulator, CFTR; Mendelian Inheritance in Man, MIM 602421) and erythropoietin (EPO; MIM 133170), as well as gene families such as the T-cell receptor gene family and the homeobox A gene family have made chromosome 7 a focus of interest for human genetics research. The gene discussed is EPO; the disease is cystic fibrosis.