DNA testing for fragile X syndrome in schools for learning difficulties.

摘要: Fragile X syndrome is the most common inherited cause of mental retardation. Early diagnosis important not only for appropriate management individuals but also to identify carriers who are unaware their high risk having an affected child. The disorder associated with a cytogenetically visible fragile site (FRAXA) at Xq27.3, caused by amplification (CGG)n repeat sequence within gene this locus designated FMR1. Clinical and molecular studies have been undertaken screen in 154 children moderate severe learning difficulties previously unknown origin. Southern blot analysis peripheral blood showed characteristic abnormally large four children. findings were confirmed cytogenetic observation further studies. families offered genetic counselling DNA tests determine carrier status. These show that there still unrecognised cases syndrome. Given difficulty making clinical implications when missed, screening populations may be justified. issues involved all special schools discussed.