Anticipation is seen in

Ref: Robbin's Pathology, 9th ed. pg. 168* Anticipation is a phenomenon where by the symptoms of a genetic disorder become apparent at an earlier age as it is passed to next generation. In most cases, an increased severity of symptoms is also noted.* In triplet nucleotide repeat mutation, the DNA fragment is unstable and tends to expand further during cell division.So, in successive generations the expanded repeat increases and the manifestations of disease may worsen or may be observed at an earlier age; this phenomenon is referred to as anticipation.