Anticipation in schizophrenia: A review and reconsideration

Melvin G. McInnis, Francis J. McMahon, Timothy Crow, Christopher A. Ross, Lynn E. DeLisi

Research output: Contribution to journalReview articlepeer-review


There have been several reports on anticipation and schizophrenia, and the purpose of the present article is to review the literature and present data from an ongoing family study of schizophrenia. The published data find on average a 10-year difference in the age of onset between the parental and offspring generation in family sets that have been ascertained for a genetic linkage study. The biases inherent in such studies include the biases of ascertainment that were described by Penrose [1948]. Several investigators have searched for evidence of enlarged triplet repeats, and some find evidence consistent with expanded triplet repeats, whereas others do not. In any event the phenomenon of anticipation in schizophrenia appears to be consistently found and an explanation is needed. Data are presented from pairwise analyses using intergenerational pairs from 61 pedigrees with schizophrenia showing evidence of anticipation as well as the fertility bias. Anticipation was found in aunt:niece/nephew pairs (14.5 years) but not in uncle:niece/nephew pairs (0.5 years). The sex difference in age of onset was accentuated in uncles versus aunts (8.5 years), present in parents (4.5 years), but absent in the proband generation. Therefore, there appears to be an interaction within families between age of onset and sex that deserves further investigation.

Original languageEnglish (US)
Pages (from-to)686-693
Number of pages8
JournalAmerican Journal of Medical Genetics - Neuropsychiatric Genetics
Issue number6
StatePublished - Dec 15 1999


  • Anticipation
  • Genetics
  • Psychiatry
  • Schizophrenia
  • Triplet repeats

ASJC Scopus subject areas

  • Genetics(clinical)
  • Psychiatry and Mental health
  • Cellular and Molecular Neuroscience


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