Thesis Abstract and Dissertation Abstracts

Mental Retardation (MR) is manifestation of brain dysfunction that originates during developmental period resulting in limitation of two or more adaptive skills i.e. communication, self care, home living, social skills, self direction, health, safety and work etc. Idiopathic mental retardation refers to individuals who show no evidence of gross chromosomal defects or single gene anomalies. It is due to variety of genetic and environmental factors. In about 5% of cases mental retardation is transmitted genetically usually through chromosomal anomalies such as Down syndrome in which there is an extra chromosome 21. MR may be caused by problems that occur during pregnancy and birth including nutritional deficiencies, pelvic inflammations (bacterial, clamydial, fungal), systemic infections (bacterial, viral, protozoal), respiratory infections, psychiatric disorders, radiation exposure, any fall or accident.

In India, incidence of mental retardation is reported to be 2-3% and of these 30% cases of severe mental retardation are genetically determined. In present study, chromosomal investigations were carried out on peripheral blood lymphocytes of 26 patients referred to Department of Human Genetics from district Kangra, Himachal Pradesh during 2010-2011. These cases had been referred cases of suspected Down syndrome, mental retardation, delayed milestones, congenital anomalies. Apart from lymphocyte culturing, detailed questionnaire was taken for patient’s history, pedigree analysis and mother’s obstetric history. Age group of cases ranged between 6-17 years (16 males, 14 females). Out of these cases, 2 patients were suspected for Down syndrome. Peripheral blood was withdrawn with parental and caretaker’s written consent. Normal chromosomal constitution was found in 8 mental retardation patients and only 1 was confirmed with Down syndrome having free trisomy 21.