title: Local gyrification index in probands with psychotic disorders and their first-degree relatives.
abstract: BACKGROUND
  Psychotic disorders are characterized by aberrant neural connectivity. Alterations in gyrification, the pattern and degree of cortical folding, may be related to the early development of connectivity. Past gyrification studies have relatively small sample sizes, yield mixed results for schizophrenia, and are scant for psychotic bipolar and schizoaffective (SZA) disorders and for relatives of these conditions. Here, we examine gyrification in psychotic disorder patients and their first-degree relatives as a possible endophenotype.
  
  
  METHODS
  Regional local gyrification index (LGI) values, as measured by FreeSurfer software, were compared between 243 control subjects, 388 psychotic disorder probands, and 300 of their first-degree relatives. For patients, LGI values were examined grouped across psychotic diagnoses and then separately for schizophrenia, SZA, and bipolar disorder. Familiality (heritability) values and correlations with clinical measures were also calculated for regional LGI values.
  
  
  RESULTS
  Probands exhibited significant hypogyria compared with control subjects in three brain regions and relatives with Axis II cluster A disorders showed nearly significant hypogyria in these same regions. Local gyrification index values in these locations were significantly heritable and uncorrelated with any clinical measure. Observations of significant hypogyria were most widespread in SZA.
  
  
  CONCLUSIONS
  Psychotic disorders appear to be characterized by significant regionally localized hypogyria, particularly in cingulate cortex. This abnormality may be a structural endophenotype marking risk for psychotic illness and it may help elucidate etiological underpinnings of psychotic disorders.
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Columbia University College of Physicians & Surgeons, New York, New York.
authors.forename: Pranav
authors.initials: P
authors.lastname: Nanda
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Baylor College of Medicine, Houston, Texas.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Tandon
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
authors.forename: Ian T
authors.initials: IT
authors.lastname: Mathew
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
authors.forename: Christoforos I
authors.initials: CI
authors.lastname: Giakoumatos
authors.affiliation: Bangalore Medical College and Research Institute, Bangalore, India.
authors.forename: Hulegar A
authors.initials: HA
authors.lastname: Abhishekh
authors.affiliation: Department of Psychology , BioImaging Research Center, University of Georgia, Athens, Georgia; Department of Neuroscience, BioImaging Research Center, University of Georgia, Athens, Georgia.
authors.forename: Brett A
authors.initials: BA
authors.lastname: Clementz
authors.affiliation: Olin Neuropsychiatry Research Center, Institute of Living, Hartford, Connecticut; Departments of Psychiatry and Neurobiology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Godfrey D
authors.initials: GD
authors.lastname: Pearlson
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: John
authors.initials: J
authors.lastname: Sweeney
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Tamminga
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Department of Psychiatry, Harvard Medical School, Boston, Massachusetts. Electronic address: keshavanms@gmail.com.
authors.forename: Matcheri S
authors.initials: MS
authors.lastname: Keshavan
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000235:genetics / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology*; D058068:Endophenotypes; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011618:Psychotic Disorders / Q000235:genetics / Q000473:pathology*; D012559:Schizophrenia / Q000235:genetics / Q000473:pathology
keywords: Bipolar; cortical folding; gyrification; psychosis; schizoaffective; schizophrenia