The identification of a third fragile site, FRAXF, in Xq27 — q28 distal to both FRAXA and FRAXE

摘要: FRAXA is unique amongst fragile sites in that it intimately involved with a specific clinical phenotype, the X syndrome. Whilst majority of individuals have been found to characteristic mutation FMR1 gene, small proportion exhibiting fragility no such mutation. Investigation site chromosome these negative, positive individuals, has identified second fragility, FRAXE. However, presence FRAXE not explained all cases. Here we describe positive, negative family, which due or but third designated FRAXF. Using fluorescent situ hybridisation (FISH) this shown lie over 1Mb distal FRAXA. The identification region provides an opportunity extend our studies molecular nature fragility.