정신지체 환자의 세포유전학적 분석

Abstract

Objects : The cytogenetic study was designed to investigate the association between mental retardation and chromosomal disorders including fragile X. Methods : Subjects were consists of 30 children(17 males, 13 females) and their age varied 24 to 228 months. The severities of mental retardation were mild in 26 patients, moderate in 1 patient and severe in 3 patients. The peripheral blood was cultured in medium 199 with methotrexate and without methotrexate for 70 hours. Thirty metaphase cells, in each were karyotype in all samples. Results : Chromosomal abnormalities were found in 10 patients, but fragile X was negative in according to Jacob's positive criteria((???)4%) in all patients, although I fragile ×(3.3%) was found in 1 patient. Chromosomal abnormalities were present on group A, B, C, D, E and X. There was no regional specificity of chromosomal abnormalities. Types of chromosomal disorders were only fragile and/or gap but no numerical abnormality was present in all cases(46XX or 46XY). Number of cells which revealed fragile sites were 29 cells(3.2%) out of 900 cells. Number of cells which revealed gaps were 35 cells(3.9%) out of 900 cells. Conclusions : These results suggest that fragile X syndrome was not found in mentally retarded patients. If further studies are performed in larger sample size, selected objects and special blood culture methods, the results may change.