RETESTING FOR FRAGILE-X-SYNDROME IN CYTOGENETICALLY NORMAL MALES

This case series describes four males who presented with learning and behavioural difficulties. In each case, the diagnosis of fragile X syn drome was delayed because of an initial false-negative cytogenetic res ult. Although most children are currently investigated for fragile X s yndrome using highly sensitive and specific molecular techniques, ther e still remain a large number of older children who have been tested u sing only cytogenetic analysis. The clinical presentation of these fou r children and the reason for the occurrence of the false-negative res ults are considered, In addition, there is a discussion and illustrati on of how a screening checklist can be used to help clinicians to deci de which children should be retested.