Schizophrenia: a genetic perspective (review)

Abstract

Schizophrenia is a complex neurodevelopmental disorder characterized by mental dysfunction across multiple domains of the brain. It affects 1% of world's general population and the nature of neurobiological lesions in the schizophrenic brain are not known. Although the exact etiology of the disorder is not understood, twin, family and adoption studies have provided consistent evidence that genetic factors play a major role in the pathogenesis. A genome-wide genetic linkage screen identified loci on chromosomes 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 18, 22 and the X with positive lod scores, thus excluding a single major locus for schizophrenia. Association studies have generated disappointing results in identifying the susceptible DNA sequence variants and the anticipation hypothesis on trinucleotide repeat expansion provided equivocal results or lack of enthusiasm. Although there are no biological markers at present, the recent finding that human endogenous retrovirus is activated in cerebrospinal fluid as well as in the postmortem schizophrenic brain may change our understanding of the etiopathogenesis of this disease. Meanwhile, treatment with newly developed anti-psychotic drugs combined with educational and cognitive rehabilitation procedure may help the patients to cope with the illness.