title: Evaluation of spontaneous dense array gamma oscillatory activity and minor physical anomalies as a composite neurodevelopmental endophenotype in schizophrenia.
abstract: OBJECTIVE
  Minor physical anomalies (MPAs) and gamma oscillatory activity have been proposed as associated endophenotypes in schizophrenia. Combining these endophenotypes to create a composite endophenotype may help identify those at risk for schizophrenia better. The present study aims to investigate MPAs and gamma oscillatory activity in schizophrenia patients, their unaffected first degree relatives and healthy controls and appreciate whether they can be used together as a composite endophenotype.
  
  
  METHODS
  This was a cross sectional family study conducted at a tertiary care mental health setup. Ninety participants including schizophrenia patients, their first degree relatives and controls (thirty each) were assessed for MPAs on the Extended Waldrop Scale. All participants underwent an awake, resting 192-channel EEG recording. Spectral power and coherence in 30-100Hz gamma bands were estimated using Welch's averaged periodogram method. One-way ANOVA, chi square test were used for comparing socio-demographic-clinical variables. MANOVA supplemented by one-way ANOVAs (post hoc Tukey HSD) were done for comparison of spectral measures. Pearson's correlation, step-by-step linear discriminant functional and intra-familial correlation analysis were subsequently performed.
  
  
  RESULTS
  An endophenotype pattern of finding was found for MPAs in the craniofacial region, the total number of MPAs, spectral power in right temporal region on all bands and in the right parietal region in 50-70Hz and 70-100Hz gamma bands. The three groups were most accurately classified when MPA total score, right temporal 30-50Hz gamma power and right occipital 'intra hemispheric' 50-70Hz gamma coherence were considered together than when considered independently. Significant intra familial correlation was seen for MPA total score and right temporal gamma 30-50Hz power.
  
  
  CONCLUSIONS
  Composite evaluation of two developmentally linked markers i.e. MPAs and gamma spectral measures may prove useful in categorizing schizophrenia and identifying at-risk individuals.
authors.affiliation: KS Mani Center for Cognitive Neurosciences and Department of Psychiatry, Central Institute of Psychiatry, Kanke, Ranchi, Jharkhand 834006, India. Electronic address: cricsai@gmail.com.
authors.forename: Sai Krishna
authors.initials: SK
authors.lastname: Tikka
authors.affiliation: KS Mani Center for Cognitive Neurosciences and Department of Psychiatry, Central Institute of Psychiatry, Kanke, Ranchi, Jharkhand 834006, India.
authors.forename: S Haque
authors.initials: SH
authors.lastname: Nizamie
authors.affiliation: KS Mani Center for Cognitive Neurosciences and Department of Psychiatry, Central Institute of Psychiatry, Kanke, Ranchi, Jharkhand 834006, India.
authors.forename: Nishant
authors.initials: N
authors.lastname: Goyal
authors.affiliation: Department of Psychopharmacology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka 560029, India.
authors.forename: N
authors.initials: N
authors.lastname: Pradhan
authors.affiliation: Department of Clinical Psychology, Central Institute of Psychiatry, Kanke, Ranchi, Jharkhand 834006, India.
authors.forename: Deyashini Lahiri
authors.initials: DL
authors.lastname: Tikka
authors.affiliation: Division of Psychiatry and Applied Psychology, School of Medicine, University of Nottingham, NG7 2TU, United Kingdom.
authors.forename: Mohammad Zia Ul Haq
authors.initials: MZ
authors.lastname: Katshu
mesh_terms: D000015:Abnormalities, Multiple / Q000209:etiology*; D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D002658:Developmental Disabilities / Q000209:etiology*; D004569:Electroencephalography; D004576:Electromyography; D058068:Endophenotypes; D005260:Female; D005583:Fourier Analysis; D007839:Functional Laterality; D065818:Gamma Rhythm / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D012559:Schizophrenia / Q000150:complications*; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Endophenotype; Minor physical anomalies; Neurodevelopment; Resting state gamma; Schizophrenia