Abstract for presentation at 11th International Congress of Human Genetics

What is familial about familial bipolar affective disorder? Resemblance among relatives across a broad spectrum of phenotypic characteristics

  • Dr Thomas Schulze, Div. of Genetic Epidemiology, Central Inst. of Mental Health, Mannheim (Germany) & NIMH/NIH, Bethesda, MD (USA), Germany
  • Dr Don Hedeker, 3) Division of Epidemiology & Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, IL, USA, United States
  • Dr Peter Zandi, 4) Department of Mental Health, The Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, MD, USA, United States
  • Dr Marcella Rietschel, Div. of Genetic Epidemiology in Psychiatry, Central Inst. of Mental Health, Mannheim (Germany), Germany
  • Dr Francis McMahon, Genetic Basis of Mood & Anxiety Disorders, Mood & Anxiety Disorders Program, NIMH, NIH, Bethesda, MD (USA), United States

    • Introduction: Traditional diagnostic criteria for bipolar affective disorder (BPAD) define a phenotype that is highly heritable, yet clinically variable. A more homogeneous definition might aid genetic and other biological studies. However, there is no consensus yet on how best to pursue such an approach. Familial characteristics of BPAD should help define more homogeneous subtypes, but there are few data indicating which phenotypic characteristics of BPAD are the most familial. In our study, we set out to explore the familiality of phenotypic characteristics in families ascertained through individuals with BPAD.
    Method: We studied 1246 individuals in 172 multiplex families ascertained for genetic linkage studies of BPAD. The familiality of 40 diverse phenotypic characteristics was studied using mixed-effects regression analysis.
    Results: Substance abuse, alcoholism, psychosis, history of suicide attempt, and the level of social functioning were all strongly familial in this sample. Several other traits, including clinical subtype, earliest age at onset, and comorbid panic disorder, showed a suggestion of familiality that did not hold up to conservative correction for multiple testing.
    Conclusion: This is the largest study to assess the familiality of phenotypic features in BPAD and the most comprehensive. Our results suggest that comorbid conditions and social functioning should be considered along with other familial clinical features in formulating subtypes of bipolar disorder suitable for further studies. Familial variables may help reduce diagnostic heterogeneity in genetic and other biological studies.

    Conference Organiser - ICMS Pty Ltd