In this paper we show that the only known Na+ dependent transporter of carnitine in mammals, organic cation transporter number 2 (OCTN2), is subject to differential splicing. Cloning of OCTN2 in different rat tissues identified two splicing variants. We have developed a real time quantitative polymerase chain reaction method for quantification of these splice variants. Both splice variants could be detected in all tissues examined with a relative abundance of 0.1–1% of the full length transcript. We also draw attention to the previously described mutations in clinical examples of primary carnitine deficiency in humans where the described mutations appear to be those of a splicing or mis-splicing event.
