[Current concepts of anticipation in endogenous psychoses]

It has been recently discovered that anticipation may correlate with expansion of trinucleotide repeats in human genome. Therefore some diseases that show anticipation, such as bipolar affective disorders and schizophrenia, deserve to be studied. Anticipation used to be considered as a result of the onset age hereditability that may be described as a lineal decrease of the age of manifestation in the following generation. Positive assortative matings leading to genes predisposed to schizophrenia ascertainment as well might be responsible for earlier onset and disease severity in descendants (Shakhmatova-Pavlova et al., 1979; Trubnikov et al., 1978; Gindilis, 1979). Therefore, clinical genetic data are to be used as the basis for anticipation study. To exclude statistical artifacts, it seems necessary to study three generations in families and proband parent siblings as a control group. The phenomena of anticipation can be regarded as a special case when a relationship between clinical and molecular genetic traits is found. In a common case, trinucleotide expansion study on the basis of vast experimental clinical family material suppose to be sensible to elucidate the correlations between the clinical level of disease description and molecular genetic characteristics. Another approach to the problem is to ascertain special relative groups to compare with. For example, the concordant and discordant monozygotic tween pairs study also seems to be promising because the molecular genetic characteristic of genome instability may help in the elucidation of protection mechanisms that prevent disease manifestations.