BMP4 and Tangier disease: In our previous study, we had identified the p.R269Q variant in exon 4 of the Bone morphogenetic protein 4 (BMP4) gene in Chinese patients with unexplained primary iron overload by Whole Exome sequencing, and then the BMP4 p.H251Y variant was identified by Sanger sequencing in a Chinese patient with secondary iron overload.