22q11DS exhibits a characteristic IQ profile ranked from relatively strongest to weakest as PS > WM > VIQ > PIQ, consistent across age groups and SSD status, with scores highest in children, lower in adolescents, and lowest in adults.
Key Findings
Results
Individuals with 22q11DS showed a characteristic IQ profile with significant differences between cognitive domains, ranked from relatively strongest to weakest: Processing Speed > Working Memory > Verbal IQ > Performance IQ.
Sample included 1,328 individuals with 22q11DS from the International Brain and Behavior Consortium, representing the largest 22q11DS sample to date.
Differences between IQ domains were statistically significant (p < 0.001).
IQ scores were derived from age-appropriate Wechsler scales at initial assessment.
The profile ranking (PS > WM > VIQ > PIQ) represents relative strengths and weaknesses within the syndrome, not absolute scores.
Results
The characteristic IQ domain profile in 22q11DS was similar across three developmental age groups (children, adolescents, and adults).
Cross-sectional and longitudinal IQ data from a subset of 496 individuals (37.35% of the total sample) were used to examine IQ profiles across age groups.
IQ scores were highest in children, lower in adolescents, and lowest in adults across all domains.
The relative ranking of domains (PS > WM > VIQ > PIQ) remained consistent regardless of developmental stage.
Domain-specific differences across age groups were noted, suggesting potentially differing underlying mechanisms.
Results
Individuals with 22q11DS without schizophrenia spectrum disorders (SSDs) had significantly higher IQ scores than those with SSDs, but without significant domain-specific differences between the two groups.
The difference in IQ scores between individuals with and without SSDs was statistically significant (p < 0.001).
No significant domain-specific effects were found when comparing profiles of individuals with versus without SSDs.
Both groups showed the same overall domain ranking (PS > WM > VIQ > PIQ).
These findings indicate the tendency toward a characteristic IQ profile in 22q11DS regardless of SSD status.
Discussion
The relative weakness in Performance IQ (PIQ) compared to other cognitive domains suggests that functional expectations for individuals with 22q11DS are likely to be overestimated.
PIQ was the weakest domain in the IQ profile across all age groups and SSD status groups.
The authors note that PIQ is particularly relevant to real-world functional abilities.
The authors conclude that clinicians may overestimate functional capabilities if relying on overall or verbal IQ scores alone.
This finding has direct clinical implications for educational and vocational planning for individuals with 22q11DS.
Discussion
The domain-specific IQ differences observed across age groups highlight the need for repeated and comprehensive cognitive assessments in individuals with 22q11DS.
Longitudinal data from 496 individuals were used to assess changes in cognitive profiles over developmental stages.
Scores were highest in children and declined through adolescence into adulthood across all domains.
The authors suggest that differing trajectories across domains may indicate differing underlying neurobiological mechanisms.
The findings support the need for ongoing cognitive monitoring rather than single-timepoint assessments in this high-risk population.
What This Means
This research suggests that people with 22q11.2 deletion syndrome (22q11DS), a genetic condition caused by a small missing piece of chromosome 22, show a consistent pattern of cognitive strengths and weaknesses. Across a very large international sample of 1,328 individuals, the study found that processing speed was the relatively strongest cognitive skill, followed by working memory, then verbal intelligence, with visual-spatial or performance-based intelligence being the weakest. This ranking held true across children, adolescents, and adults, and was present whether or not individuals had also developed schizophrenia or related psychiatric disorders.
The study also found that cognitive scores were generally highest in children and declined through adolescence into adulthood for all domains, and that individuals who developed schizophrenia spectrum disorders scored lower overall but showed the same relative pattern of cognitive strengths and weaknesses as those without such disorders. The finding that performance-based IQ is the weakest domain is particularly important because this type of intelligence is closely tied to everyday functional abilities.
This research suggests that clinicians and educators may be overestimating the practical, real-world capabilities of individuals with 22q11DS if they rely mainly on overall or verbal IQ scores. It also highlights the importance of testing multiple areas of cognition repeatedly over time rather than conducting a single assessment, as the cognitive landscape in this syndrome shifts across development and may reflect different underlying brain processes for different skill areas.
Fiksinski A, Wierenga R, McDonald-McGinn D, S Bassett A, Bearden C, Morrow B, et al.. (2026). The uneven landscape of cognitive domains in 22q11.2 deletion syndrome: A large consortium study.. Psychological medicine. https://doi.org/10.1017/S0033291726105224