Single gene disorders

Where genetic disorders are the result of a single mutated gene they can be passed on to subsequent generations in the ways outlined in the table below. Genomic imprinting and uniparental disomy, however, may affect inheritance patterns. The divisions between recessive and dominant are not "hard and fast" although the divisions between autosomal and X-linked are (related to the position of the gene). For example, achondroplasia is typically considered a dominant disorder, but children with two genes for achondroplasia have a severe skeletal disorder that achondroplasics could be viewed as carriers of. Sickle-cell anemia is also considered a recessive condition, but carriers that have it by half along with the normal gene have increased immunity to malaria in early childhood, which could be described as a related dominant condition