CONSTITUTIVE HETEROCHROMATIN OF CHROMOSOME-1 AND DUFFY BLOOD-GROUP ALLELES IN SCHIZOPHRENIA

Cytogenetic analysis was carried out in unrelated schizophrenic patien ts, unrelated controls and patients and family members in multiplex fa milies, The size distribution of chromosome 1 heterochromatic region ( 1qH, C-band variants) among 21 unrelated schizophrenic patients was di fferent from that found in a group of 46 controls, The patient group h ad 1qH variants of smaller size than the control group (P < 0.01), Inc ubation of phytohemagglutinin-treated blood lymphocytes with 5-azacyti dine (which causes decondensation and extension of the heterochromatin ) led to a lesser degree of heterochromatin decondensation in a group of patients than in the controls (7 schizophrenic, 9 controls, P < 0.0 1). The distribution of phenotypes of Duffy blood group system [whose locus is licked to the 1qH region (Donahue et al.: Proc Natl Acad Sci USA 61:949-955, 1968; Rouleau et al.: Genomics 7:313-318, 1990)] among 28 schizophrenic patients was also different from that in the general population, Cosegregation of schizophrenia with a 1qH (C-band) varian t and Duffy blood group allele was observed in one of six multiplex fa milies, The overall results suggest that alterations within the Duffy/ 1qH region are involved in schizophrenia in some cases, This region co ntains the locus of D5 dopamine receptor pseudogene 2 (1q21.1), which is transcribed in normal lymphocytes (Takahashi et al.: FEES Lett 314: 23-25, 1992). (C) 1995 Wiley-Liss, Inc.