SINGLE-GENE DISEASES

Hereditary disorders caused by a change (mutation) in a single gene. There are thousands of single-gene diseases including achondroplastic dwarfism, Huntington disease, cystic fibrosis, sickle cell disease, Duchenne muscular dystrophy, and hemophilia. Single-gene diseases typically describe classic simple Mendelian patterns of inheritance (as autosomal dominant, autosomal recessive, and X-linked traits) by comparison with polygenic diseases.