Chromosomal Study of 100 Children and Adolescenes With Mental Retardation

About 3-5 percent of population suffer from mental retardation (MR) mildly to severely. One of the most common causes of Mr is chromosomal aberrations. In this research, Chromosmal study was performed for 100 Mental Retarders (MRS) by G-banding Method. 100 MRS were suffering from downs syndromes: 21 cases with 21 free Trisomy, 1 case chromosomal mosaism and residual case had Robertsonian traslocation 14; 21 also chromosomal mosaism. Other 8 MRS had be structural aberrations in chromosmals such as inversion (3 cases), partial trisomy (1 case), ring 22 chromosme (1 case) and breakages in different chromosmes (3 cases). The results showed that chromosomal aberrations are frequent between Mental Retarderes and the most common chromosomal aberrations occure between MRS is 21 free trisomy.