anticipation

The tendency in certain genetic disorders for individuals in successive generations to present at an earlier age and/or with more severe manifestations; often observed in disorders resulting from the expression of a trinucleotide repeat mutation that tends to increase in size and have a more significant effect when passed from one generation to the next

Posted: 10-1-02

Related Terms: intrafamilial variability; mutable normal allele; trinucleotide repeat; trinucleotide repeat testing; variable expressivity