Several years ago, we initiated a long-term project of cloning new human 
ATP-binding cassette (ABC) transporters and linking them to various disease 
phenotypes. As one of the results of this project, we present two new members of 
the human ABCC subfamily, ABCC11 and ABCC12. These two new human ABC 
transporters were fully characterized and mapped to the human chromosome 16q12. 
With the addition of these two genes, the complete human ABCC subfamily has 12 
identified members (ABCC1-12), nine from the multidrug resistance-like subgroup, 
two from the sulfonylurea receptor subgroup, and the CFTR gene. Phylogenetic 
analysis determined that ABCC11 and ABCC12 are derived by duplication, and are 
most closely related to the ABCC5 gene. Genetic variation in some ABCC subfamily 
members is associated with human inherited diseases, including cystic fibrosis 
(CFTR/ABCC7), Dubin-Johnson syndrome (ABCC2), pseudoxanthoma elasticum (ABCC6) 
and familial persistent hyperinsulinemic hypoglycemia of infancy (ABCC8). Since 
ABCC11 and ABCC12 were mapped to a region harboring gene(s) for paroxysmal 
kinesigenic choreoathetosis, the two genes represent positional candidates for 
this disorder.