what are the different genetic diseases
1 Dominant diseases: single gene disorders that occur when an individual has one altered copy of the relevant gene and one healthy copy. For example, Huntingtonâs disease.  Recessive diseases: single gene disorders that only occur when an individual has two altered versions of the relevant gene.
1 For example, Huntingtonâs disease. 2  Recessive diseases: single gene disorders that only occur when an individual has two altered versions of the relevant gene. For example, cystic fibrosis.  X-linked disorders: single gene disorders that reflect the presence of an altered gene on the X chromosome.