IgA measurements in over 12 000 Swedish twins reveal sex differential heritability and regulatory locus near CD30L.

Alexander Viktorin, Marcel Frankowiack, Leonid Padyukov, Zheng Chang, Erik Melén, Annika Sääf, Inger Kull, Lars Klareskog, Lennart Hammarström, Patrik K E Magnusson

Human molecular genetics 2014 Aug 01

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In a broad attempt to improve the understanding of the genetic regulation of serum IgA levels, the heritability was estimated in over 12 000 Swedish twins, and a genome-wide association study was conducted in a subsample of 9617. Using the classical twin model the heritability was found to be significantly larger among females (61%) compared with males (21%), while contribution from shared environment (20%) was only seen for males. By modeling the genetic relationship matrix with IgA levels, we estimate that a substantial proportion (31%) of variance in IgA levels can ultimately be explained by the investigated SNPs. The genome-wide association study revealed significant association to two loci: (i) rs6928791 located on chromosome 6, 22 kb upstream of the gene SAM and SH3 domain containing 1 (SASH1) and (ii) rs13300483 on chromosome 9, situated 12 kb downstream the CD30 ligand (CD30L) encoding gene. The association to rs13300483 was replicated in two additional independent Swedish materials. The heritability of IgA levels is moderate and can partly be attributable to common variation in the CD30L locus. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Citation

Alexander Viktorin, Marcel Frankowiack, Leonid Padyukov, Zheng Chang, Erik Melén, Annika Sääf, Inger Kull, Lars Klareskog, Lennart Hammarström, Patrik K E Magnusson. IgA measurements in over 12 000 Swedish twins reveal sex differential heritability and regulatory locus near CD30L. Human molecular genetics. 2014 Aug 01;23(15):4177-84