Figure 1. Schematic representation of the MRP6 protein. The protein contains 17 membrane-spanning domains and two intracellular nucleotide binding folds (NBFs). The percentages in the figure show how the mutations in our population are distributed over the different domains of the protein. The eighth cytoplasmatic loop is the most frequently mutated domain, followed by the region between the last transmembrane-spanning domain and NBF2 and by NBF2 itself. Del=deletion. In addition, 1% of the population had a deletion of the whole gene.