The cytogenetic investigation of the patients with neuropsychiatric and mental retardation

ABSTRACT The Cytogenetic Investigation of the Patients with Neuropsychiatric and Mental Retardation Neuropsychiatric diseases are a group of multifactorial^ inherited disorders, in which genetic factors and negative environmental conditions have important roles for the development of the diseases. In this subject, cytogenetics and molecular genetic studies have been done besides of twin and adoption studies. It is reported that the frequencies of chromosomal aberrations and chromosomal fragile sites are increased in patients with the diseases. This study includes 193 patients with schizophrenia (134 patients), bipolar disorders (17 patients), other psychosis (25 patients), epilepsy (5 patients) and mental retardation (12 patients) from psychiatric and neurologic diseases hospital in Adana, and 30 healthy control individuals. Chromosomal analysis of patient and control groups were performed using normal and folat-deficient mediums. Our results show an increasing genetic instability in patient group according to the control group. In the patient group, the incidence of numerical and structural chromosomal aberrations and chromosomal fragile sites were found to increase. In addition, in this study, the effects of sex differences and age on the frequency of fragility were evaluated. We have demonstrated that the frequencies of fragility in males is higher than in females and there is no age effect on the frequency of fragility. In our study, we established a relationship between chromosomal aberrations, neuropsychiatric diseases and mental retardation, which is supported with literature. Our findings support that the fragile sites where candidate genes may be localized were not distrubuted randomly, but rather aggregated in spesific chromosomal bands for each disease and candidate genes are perhaps localized on these regions. Thus, the potential relation between fragile sites and neuropsychiatric diseases have been argued. We believe that our results may contribute cytogenetic, molecular and population genetic studies for the investigation of major candidate genes that may have a role in the etiology of neuropsychiatric diseases. Key words: Neuropsychiatric diseases, Mental retardation, Chromosomal analysis, Fragile sites, Chromosomal aberrations. Xll