Table Examples of Genetic Disorders With Mendelian Inheritance Gene Dominant Recessive Non-X-linked Marfan syndrome Huntington disease Cystic fibrosis X-linked Familial rickets Hereditary nephritis Red-green color blindness Hemophilia Autosomal Dominant Only one abnormal allele of a gene is needed to express an autosomal dominant trait; ie, both heterozygotes and homozygotes for the abnormal gene are affected.