ATP-binding cassette (
ABC) transporters are involved in a variety of physiologic processes such as
xenobiotic defense, lipid metabolism, ion homeostasis and immune functions. A large number of ABC
proteins have been causatively linked to rare and common human
genetic diseases including familial
high-density lipoprotein deficiency, retinopathies,
cystic fibrosis, diabetes and
cardiomyopathies. Furthermore, genetic variations in
ABC transporter genes and dysregulated expression patterns of these molecules significantly contribute to drug resistance in human
cancer cells and alter the pharmacokinetic properties of a variety of drugs. In order to analyze DNA sequence alterations or define disease-associated
mRNA expression patterns of the complete
ABC transporter superfamily, novel high-throughput molecular methods such as quantitative real-time PCR and
DNA microarray analysis are emerging. The aim of this review is to provide an overview and to present some examples of human
ABC transporters involved in monogenic diseases,
cancer and pharmacogenetics. Methodologic aspects of molecular diagnostics applied to analyze genetic variations,
mRNA and
protein expression levels and functional characteristics of
ABC transporters are discussed.