The phenotype of many inherited disorders tends to become progressively more severe and/or be expressed at a younger age as it is transmitted to successive generations of a pedigree. This phenomenon is called anticipation and has been reported to occur widely in the principal functional psychoses (schizophrenia and bipolar disorder), although it is possible that these findings are attributable to sampling biases.
Keywords: age at onset; bipolar disorder; disease severity; repeat expansion detection; schizophrenia





