ABCC6 and its transcribed pseudogene ABCC6P1 are co-expressed in a variety of human tissues. Relative transcription levels of ABCC6 (A) and ABCC6P1 (B) were determined in 20 different human tissues by real-time RT-PCR relative to those of the housekeeping gene β-actin. Highest expression of both ABCC6 and ABCC6P1 was observed in adult liver (reference = 100%), kidney and fetal liver. (C) ABCC6/ABCC6P1 transcript ratios. Note that ABCC6 and ABCC6P1 are co-expressed in all tissues investigated with the ABCC6 expression levels being on average 2–4 times higher than those of ABCC6P1. Ratios are shown in a logarithmic scale (base 2).