Contrary to the aforementioned results, smaller studies of genetic variation in ABCA1 (ATP-binding cassette transporter 1) demonstrated that R230C variant was associated with increased risk of type 2 diabetes [56], while loss-of-function mutations in ABCA1 were proposed to correlate with impaired β-cell function, but not with development of type 2 diabetes [57]. Here, ABCA1 is linked to type 2 diabetes mellitus.