BACKGROUND/AIMS: Maternal and offspring cell contact at the site of placentation presents a plausible setting for maternal-fetal genotype (MFG) interactions affecting fetal growth. We test hypotheses regarding killer cell immunoglobulin-like receptor (KIR) and HLA-C MFG effects on human birth weight by extending the quantitative MFG (QMFG) test. METHODS: Until recently, association testing for MFG interactions had limited applications. To improve the ability to test for these interactions, we developed the extended QMFG test, a linear mixed-effect model that can use multi-locus genotype data from families. RESULTS: We demonstrate the extended QMFG test's statistical properties. We also show that if an offspring-only model is fit when MFG effects exist, associations can be missed or misattributed. Furthermore, imprecisely modeling the effects of both KIR and HLA-C could result in a failure to replicate if these loci's allele frequencies differ among populations. To further illustrate the extended QMFG test's advantages, we apply the extended QMFG test to a UK cohort study and the Norwegian Mother and Child Cohort (MoBa) study. CONCLUSION: We find a significant KIR-HLA-C interaction effect on birth weight. More generally, the QMFG test can detect genetic associations that may be missed by standard genome-wide association studies for quantitative traits.
BACKGROUND/AIMS: Maternal and offspring cell contact at the site of placentation presents a plausible setting for maternal-fetal genotype (MFG) interactions affecting fetal growth. We test hypotheses regarding killer cell immunoglobulin-like receptor (KIR) and HLA-C MFG effects on human birth weight by extending the quantitative MFG (QMFG) test. METHODS: Until recently, association testing for MFG interactions had limited applications. To improve the ability to test for these interactions, we developed the extended QMFG test, a linear mixed-effect model that can use multi-locus genotype data from families. RESULTS: We demonstrate the extended QMFG test's statistical properties. We also show that if an offspring-only model is fit when MFG effects exist, associations can be missed or misattributed. Furthermore, imprecisely modeling the effects of both KIR and HLA-C could result in a failure to replicate if these loci's allele frequencies differ among populations. To further illustrate the extended QMFG test's advantages, we apply the extended QMFG test to a UK cohort study and the Norwegian Mother and Child Cohort (MoBa) study. CONCLUSION: We find a significant KIR-HLA-C interaction effect on birth weight. More generally, the QMFG test can detect genetic associations that may be missed by standard genome-wide association studies for quantitative traits.
Authors: Susan E Hiby; Richard Apps; Andrew M Sharkey; Lydia E Farrell; Lucy Gardner; Arend Mulder; Frans H Claas; James J Walker; Christopher W Redman; Christopher C Redman; Linda Morgan; Clare Tower; Lesley Regan; Gudrun E Moore; Mary Carrington; Ashley Moffett Journal: J Clin Invest Date: 2010-10-25 Impact factor: 14.808
Authors: Christina G S Palmer; Joni A Turunen; Janet S Sinsheimer; Sonia Minassian; Tiina Paunio; Jouko Lönnqvist; Leena Peltonen; J Arthur Woodward Journal: Am J Hum Genet Date: 2002-11-18 Impact factor: 11.025
Authors: Susan E Hiby; James J Walker; Kevin M O'shaughnessy; Christopher W G Redman; Mary Carrington; John Trowsdale; Ashley Moffett Journal: J Exp Med Date: 2004-10-11 Impact factor: 14.307