SDC1 and Miyoshi myopathy: Previously, we demonstrated an expression quantitative trait locus (eQTL) signal between rs4487645 and CDCA7L (ref. 10), with the risk allele associated with increased expression of CDCA7L. To further substantiate this eQTL, we analysed mRNA expression data on CD138-purified plasma cells from 1,449 MM cases from three independent series.