Genetic inheritance of schizophrenia and bipolar disorder in an Italian population isolate

Family, twin and adoption studies have shown that schizophrenia (SZ) and bipolar disorder (BP) are complex and highly heritable disorders. Heritability has been estimated around 80% in both disorders (Owen et al. 2005). Both Spectrum Disorders are genetically heterogeneous diseases and findings of linkage on different chromosomes in various studies corroborate this assumption (Kirov et al., 2005). Genetic isolates, provide outstanding opportunities for identification of susceptibility genes for complex diseases. To assess the mode of inheritance of SZ/BP spectra disorders, a complex segregation analysis, has been performed in a total sample of 40 pedigrees (553 individuals; 96 nuclear families) originating from Chioggia, population that for its characteristics can be considered an “isolated community”. POINTER indicates that polygenic, multifactorial and single locus models, provide a significantly (P