Genome-wide Identification of Variants Affecting Early Human Brain Development

This is a genome-wide association study (GWAS) of global brain tissue volumes in human infants. The published study for this project includes 561 infants, and 239 parents gave consent for data sharing through dbGaP. An intronic single-nucleotide polymorphism (SNP) in IGFBP7 (rs114518130; GeneID: 3490) met genome-wide significance for gray matter volume (P=4.15x10-10). An intronic SNP in WWOX (rs10514437; GeneID: 51741) neared genome-wide significance for white matter volume (P=1.56x10-8). Additional loci with small P-values include psychiatric GWAS associations and transcription factors expressed in the developing brain. Genetic risk scores for schizophrenia and ASD, and the number of genes affected by rare copy number variants (CNV burden) did not predict global brain tissue volumes. Integrating these results with large-scale GWAS in adolescents [Philadelphia Neurodevelopmental Cohort (PNC)] and adults [Enhancing Neuro Imaging Genetics through Meta-Analysis version 2 (ENIGMA2)] suggested minimal overlap between common variants impacting brain volumes at different ages.]]> Exclusion criteria at enrollment were the presence of abnormalities on fetal ultrasound or major medical illness in the mother. We excluded samples with low DishQC (<0.82 for LAT array and <0.79 for Exome array), low call rates (<95%), outliers for homozygosity, sex or zygosity from genotypes inconsistent with reported phenotypes, ancestry outliers, excessive relatedness, and unexpected relatedness. ]]>