Faculty Collaboration Database

Variance of IQ is partially dependent on deletion type among 1,427 22q11.2 deletion syndrome subjects. Am J Med Genet A 2018 Oct;176(10):2172-2181

Date

10/06/2018

Pubmed ID

30289625

Pubmed Central ID

PMC6209529

DOI

10.1002/ajmg.a.40359

Scopus ID

2-s2.0-85054522149 (requires institutional sign-in at Scopus site)   28 Citations

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.

Author List

Zhao Y, Guo T, Fiksinski A, Breetvelt E, McDonald-McGinn DM, Crowley TB, Diacou A, Schneider M, Eliez S, Swillen A, Breckpot J, Vermeesch J, Chow EWC, Gothelf D, Duijff S, Evers R, van Amelsvoort TA, van den Bree M, Owen M, Niarchou M, Bearden CE, Ornstein C, Pontillo M, Buzzanca A, Vicari S, Armando M, Murphy KC, Murphy C, Garcia-Minaur S, Philip N, Campbell L, Morey-Cañellas J, Raventos J, Rosell J, Heine-Suner D, Shprintzen RJ, Gur RE, Zackai E, Emanuel BS, Wang T, Kates WR, Bassett AS, Vorstman JAS, Morrow BE, International 22q11.2 Brain and Behavior Consortium

Author

Aoy Tomita Mitchell PhD Professor in the Surgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adolescent
Adult
Child
Chromosome Deletion
Chromosomes, Human, Pair 22
DiGeorge Syndrome
Female
Humans
Intellectual Disability
Intelligence Tests
Male