Analysis of Telomere Length in Patients with Mental Retardation

• Main Authors: Ching-Hua Lin, 林清華
• Other Authors: Chung-Lung Cho
• Format: Others
• Language: en_US
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/07488200308175101487

碩士 === 國立中山大學 === 生物科學系研究所 === 89 === Telomeres are located at the ends of all eukaryotic chromosomes and provide the stability of chromosomes. They consist of simple tandem hexametric repeats and play an important part in cell longevity. In human lymphocytes, telomeres shorten progressively with age. Mental retardation (MR) is a disorder with intelligence quotient below average (IQ < 70) and impairment in adaptive skills. IQ by Weschsler Adult Intelligence Scales revised (WAIS-R) appears to peak in the of 30-34 and thereafter decline gradually. Life expectancy is defined as the number of years remaining to be lived. The overall increase in life expectancy indicates an improvement in longevity. The life expectancy of MR patients is shorter than that of the general population. The purpose of this study is to predict the relationship between telomere length and IQ in normal control as well as to analyze the differences among the average telomere length for the control and subgroups of MR cases. Fifty-nine patients who met the fourth edition of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria for mental retardation were included in this study. According to the degree of intellectual impairment, MR patients were divided into 4 types: mild, moderate, severe, and profound. Fifty-two female nursing students aged 19-21 were recruited as normal controls. DNA was isolated from their lymphocytes. Telomere length was analyzed by Southern blot hybridization. The length was calculated by the Photo CaptMw Version 99.03 software. Correlation between the telomere length and IQ in normal control was performed by the Pearson product-moment correlation. One-way ANOVA was used to test if any differences existed among the normal, mild, moderate, severe, and profound MR. Analyses displayed that there were no correlations between telomere length and IQ including PIQ(r=-0.001; p=0.922), VIQ(r=-0.033; p=0.817), TIQ(r=-0.026, p=0.857), and no difference existed among the normal and subgroups of MR cases. Results obtained from this study indicated that life expectancy of MR patients may approximate to that of the general population if live in the well environment.