IGHE and atopic eczema: Manousaki D et al (20) found that four single-nucleotide polymorphisms (SNPs) strongly associated with 25-hydroxyvitamin D [25(OH)D] levels in 33,996 individuals, and conducted Mendelian randomization (MR) studies to estimate the effect of lowered 25(OH)D on the risk of asthma, atopic dermatitis, childhood onset asthma, and elevated IgE level and tested MR assumptions in sensitivity analyses.