C1QC and atrial fibrillation: Another colocalised variant between AD and AF, the intergenic rs7529220, which is located 19 k upstream from Heparan Sulfate Proteoglycan 2 (HSPG2) and 21 k downstream from Chymotrypsin Like Elastase 3B (CELA3B), was associated with increased risk of AD and AF and higher expression of three genes of the Complement Component 1, Q Subcomponent (C1Q) family (C1QA, C1QB, C1QC) in breast mammary tissue (and, by inference, in brain vasculature) and is a previously unreported locus for AD.