ABSTRACT
OBJECTIVES: This study aims at exploring genetic and clinical characteristics of multiplex Korean families with schizophrenia. METHODS: Thirty-three families having two or more schizophrenics by DSM-IV criteria within the second degree relatives were obtained from the clinics of general hospitals and mental hospitals. Sixty-nine affected and forty-five unaffected subjects from these families were interviewed using Korean version of Diagnostic Interview for Genetic Studies. Krawieka Rating Scale and The Schedule for the Deficit Syndrome were also applied for further evaluation of psychopathologies of the patients. Patterns of inheritances of the disease were analyzed by the inspection of the pedigrees. Parent-of-origin effect was evaluated by the comparison of the occurrence rate and the clinical characteristics between the subgroups of maternal and paternal origins. RESULTS: There were similar rates of maternal and paternal transmission in the families for which unilineal transmission of the disease was estimated. Only one family showed bilineal transmission. Observed patterns of transmission were not compatible with the recessive single locus model or sex-linked model. The most frequently observed non-schizophrenic disorders in these families were personality disorders/traits of schizophrenia spectrum. We could not find any clinical characteristics which might be unique to the patients from multiplex families. Parent-of-origin effect was not suggested. CONCLUSION: This study provides preliminary clinical and genetic data on the multiplex schizophrenia families which could be used for the determination of the genetic parameters and the boundaries of the phenotype in the linkage analyses.