title: Twin studies for the investigation of the relationships between genetic factors and brain abnormalities in bipolar disorder.
abstract: The pathogenesis of bipolar disorder (BD) is to date not entirely clear. Classical genetic research showed that there is a contribution of genetic factors in BD, with high heritability. Twin studies, thanks to the fact that confounding factors as genetic background or family environment are shared, allow etiological inferences. In this work, we selected twin studies, which focus on the relationship between BD, genetic factors and brain structure, evaluated with magnetic resonance imaging. All the studies found differences in brain structure between BD patients and their co-twins, and also in respect to healthy controls. Genetic effects are predominant in white matter, except corpus callosum, while gray matter resulted more influenced by environment, or by the disease itself. All studies found no interactions between BD and shared environment between twins. Twin studies have been demonstrated to be useful in exploring BD pathogenesis and could be extremely effective at discriminating the neural mechanisms underlying BD.
authors.affiliation: IRCCS 'E. Medea' Scientific Institute,Bosisio Parini,Italy.
authors.forename: L
authors.initials: L
authors.lastname: Squarcina
authors.affiliation: National Centre for Epidemiology,Surveillance and Health Promotion,Istituto Superiore di Sanità,Rome,Italy.
authors.forename: C
authors.initials: C
authors.lastname: Fagnani
authors.affiliation: Section of Psychiatry,AOUI Verona,Verona,Italy.
authors.forename: M
authors.initials: M
authors.lastname: Bellani
authors.affiliation: Department of Neurosciences and Mental Health,Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico,University of Milan,Milan,Italy.
authors.forename: C A
authors.initials: CA
authors.lastname: Altamura
authors.affiliation: Department of Neurosciences and Mental Health,Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico,University of Milan,Milan,Italy.
authors.forename: P
authors.initials: P
authors.lastname: Brambilla
mesh_terms: D001714:Bipolar Disorder / Q000235:genetics* / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D018433:Twin Studies as Topic; D014429:Twins, Dizygotic; D066127:White Matter
keywords: Twins; bipolar disorder; brain imaging; heritability; magnetic resonance imaging.; twin model