LACK OF ASSOCIATION BETWEEN MUTATION SIZE AND COGNITIVE BEHAVIOR DEFICITS IN FRAGILE-X MALES - A BRIEF REPORT/

Previously, researchers reported molecular-neurobehavioral or molecula r-cognitive associations in individuals with fra(X) (fragile X) mutati on, However, not all investigators have noted molecular-behavioral rel ationships. Consequently, we examined prospectively 30 fra(X) males ag e 3-15 years from four testing sites to determine whether there was a relationship between mutation size and degree of either cognitive or a daptive behavior deficit, To measure cognitive abilities, all individu als were administered the Stanford-Binet (4th edition) IQ test, To eva luate adaptive behavior (DQ) skills, all individuals were assessed usi ng the Vineland Adaptive Behavior Scale. To determine fra(X) status, g enomic DNA from all individuals was extracted and digested with EcoRI and EagI restriction enzymes. Southern blots were prepared and hybridi zed with the pE5.1 probe. The Pearson correlation coefficient between full mutation size and composite IQ score revealed a nonsignificant, n ear-zero association (r = 0.06; P > .76), The Pearson coefficient betw een mutation size and DQ also showed a nonsignificant, near-zero assoc iation (r = 0.06; P > .73). We conclude that while fra(X) mutation pro duces cognitive and behavior deficits in males who inherit the defecti ve gene, there is no relationship between mutation size and degree of deficit. (C) 1996 Wiley-Liss, Inc.