number of repeats will expand. As this occurs, progeny can progress to premutation and ultimately affected status. Individuals with a number of repeats that falls in the premutation range have a good chance of having affected children. Those who progress to affected status will exhibit symptoms of their particular disease. Prominent trinucleotide repeat disorders include Fragile X syndrome and Huntington's disease. In the case of Fragile X syndrome it is thought that the symptoms result from the increased methylation and accompanying reduced expression of the fragile X intellectual disability gene in individuals with a sufficient number of repeats. See also Meiotic drive CoRR Hypothesis Epigenetic inheritance Gene drive Intragenomic conflict References External links non-Mendelian inheritance at Duke University Extended evolutionary synthesis Classical genetics