학술논문

Variance of IQ is partially dependent on deletion type among 1,427 22q11.2 deletion syndrome subjects
Document Type
article
Source
American Journal of Medical Genetics Part A. 176(10)
Subject
Biological Sciences
Biomedical and Clinical Sciences
Clinical Sciences
Genetics
Acquired Cognitive Impairment
Clinical Research
Brain Disorders
Pediatric
Adolescent
Adult
Child
Chromosome Deletion
Chromosomes
Human
Pair 22
DiGeorge Syndrome
Female
Humans
Intellectual Disability
Intelligence Tests
Male
22q11.2 deletion syndrome
deletion size
intellectual disability
IQ
low copy repeat
segmental duplication
International 22q11.2 Brain and Behavior Consortium
Clinical sciences
Language
Abstract
The 22q11.2 deletion syndrome is caused by non-allelic homologous recombination events during meiosis between low copy repeats (LCR22) termed A, B, C, and D. Most patients have a typical LCR22A-D (AD) deletion of 3 million base pairs (Mb). In this report, we evaluated IQ scores in 1,478 subjects with 22q11.2DS. The mean of full scale IQ, verbal IQ, and performance IQ scores in our cohort were 72.41 (standard deviation-SD of 13.72), 75.91(SD of 14.46), and 73.01(SD of 13.71), respectively. To investigate whether IQ scores are associated with deletion size, we examined individuals with the 3 Mb, AD (n = 1,353) and nested 1.5 Mb, AB (n = 74) deletions, since they comprised the largest subgroups. We found that full scale IQ was decreased by 6.25 points (p = .002), verbal IQ was decreased by 8.17 points (p = .0002) and performance IQ was decreased by 4.03 points (p = .028) in subjects with the AD versus AB deletion. Thus, individuals with the smaller, 1.5 Mb AB deletion have modestly higher IQ scores than those with the larger, 3 Mb AD deletion. Overall, the deletion of genes in the AB region largely explains the observed low IQ in the 22q11.2DS population. However, our results also indicate that haploinsufficiency of genes in the LCR22B-D region (BD) exert an additional negative impact on IQ. Furthermore, we did not find evidence of a confounding effect of severe congenital heart disease on IQ scores in our cohort.