?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Second-trimester+markers+of+fetal+size+in+schizophrenia%3A+a+study+of+monozygotic+twins&rft.creator=Bracha%2C+HS&rft.creator=Torrey%2C+EF&rft.creator=Gottesman%2C+II&rft.creator=Bigelow%2C+LB&rft.creator=Cunniff%2C+C&rft.subject=Neuropsychiatry&rft.subject=Neurology&rft.description=OBJECTIVE%3A+Since+the+second+prenatal+trimester+is+the+critical+period+of+massive+neural+cell+migration+to+the+cortex%2C+and+fingertip+dermal+cells+migrate+to+form+ridges+during+this+same+period%2C+the+authors+sought+to+determine+whether+there+are+differences+in+fingertip+ridge+count+in+pairs+of+monozygotic+twins+discordant+for+schizophrenia%2C+possibly+indicating+that+a+prenatal+anatomical+insult+affected+the+twins+differently.+METHOD%3A+The+fingertip+dermal+ridges+of+30+pairs+of+monozygotic+twins+(23+pairs+in+which+the+twins+were+discordant+for+schizophrenia+and+seven+pairs+in+which+both+twins+were+normal)+were+counted+by+two+persons+trained+in+anthropometric+research.+Intrapair+differences+in+the+counts+were+then+measured%2C+and+the+differences+among+the+pairs+of+normal+twins+were+compared+with+the+differences+among+the+pairs+discordant+for+schizophrenia.+RESULTS%3A+The+twins+discordant+for+schizophrenia+had+significantly+greater+absolute+intrapair+differences+in+total+finger+ridge+count+and+significantly+greater+percent+intrapair+differences+than+the+normal+twins%3B+i.e.%2C+their+fingerprints+were+significantly+less+%22twin-like.%22+CONCLUSIONS%3A+The+study+suggests+that+various+second-trimester+prenatal+disturbances+in+the+epigenesis+of+one+twin+in+a+pair+discordant+for+schizophrenia+may+be+related+to+the+fact+that+only+one+of+the+twins+expresses+his+or+her+genetic+predisposition+toward+schizophrenia.+This+is+consistent+with+a+%22two-strike%22+etiology+of+schizophrenia%3A+a+genetic+diathesis+plus+a+second-trimester+environmental+stressor.&rft.date=1992-10&rft.type=Journal+(Paginated)&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.identifier=http%3A%2F%2Fcogprints.org%2F5316%2F1%2FBracha_et_al.%252C_Second_Trimester_Markers_of_Fetal_Size_-_Am_J_Psych_1992.PDF&rft.identifier=++Bracha%2C+HS+and+Torrey%2C+EF+and+Gottesman%2C+II+and+Bigelow%2C+LB+and+Cunniff%2C+C++(1992)+Second-trimester+markers+of+fetal+size+in+schizophrenia%3A+a+study+of+monozygotic+twins.++%5BJournal+(Paginated)%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F5316%2F