FREQUENCY OF FRA-X-SYNDROME AMONG INSTITUTIONALIZED MENTALLY-RETARDEDMALES IN POLAND

Results of cytogenetic studies, performed in a group of 201 institutio nalized mentally retarded males, ape presented, At least, two cytogene tic methods for eliciting the Xq27.3 fragile site, recommended by the Fourth International Workshop on the Fra X Syndrome were used, A subgr oup of 67 out of 201 studied males was also examined using molecular m ethods, In 6 (2.9%) males fra X syndrome was diagnosed, All cytogeneti c positive results were confirmed by molecular analysis, Five patients had full expansion CGG repeats and one had both premutation and full mutation, Postulated frequency of fra X syndrome in Polish population being 0.2-0.4/1,000 males seems to be lower than it could be expected on the basis of previous literature data. (C) 1996 Wiley-Liss, Inc.