The majority of patients with DiGeorge / velocardiofacial syndrome have a 22q11.2 microdeletion, demonstrable by fluorescent in-situ hybridization. As part of a prospective study of patients with such deletions, Wechsler IQ measures were administered to 13 subjects (8 female, 5 male; age range 3y1m-20y10m). Full-scale IQ (FS-IQ) averaged 74.8 ± 9.8 (mean ± standard deviation), with 4/13 subjects scoring in the low-average or average ranges. A significant discrepancy was found between mean Verbal IQ (V-IQ) and Performance IQ (P-IQ) scores (82.8 ± 12.1 vs. 70.5 ± 9.2, Wilcoxon signed rank test, z=2.76, p<0.01). Twelve out of 13 subjects showed the V-IQ > P-IQ profile, and this discrepancy was statistically significant in 7 subjects.

The Wechsler Individual Achievement Test was completed for 11 subjects. The mean Reading composite score was significantly greater than the mean Mathematics composite score (92.4± 11.6 vs. 82.8 ± 11.5, Wilcoxon signed rank test, z=2.75, p<0.01). Ten out of 11 subjects showed the Reading > Math profile, and this discrepancy was statistically significant in 6 subjects. In all but two subjects, actual reading scores exceeded scores that were predicted on the basis of either FS-IQ or V-IQ. More extensive neuropsychological study is beginning to suggest that the reading competence of these subjects may be associated with strong verbal learning skills.

A distinct profile of IQ scores and of academic achievement thus appears to be associated with microdeletions at 22q11.2, in both males and females. This profile resembles that found in children with non-verbal learning disabilities. Further research will specify the molecular and neurodevelopmental processes that result from the 22q11.2 microdeletion.