Figure 1

Schematic representation of the NPC1 protein (not to scale). Cylinders represent the transmembrane regions; the SSD domain is depicted in grey. Luminal loop 2 is represented in blue and red to account for the recombination breakpoint. The position of the three positively selected sites in loop 2 is shown (yellow circles) with the alignment of a few representative mammalian species. The position of nonsynonymous polymorphisms with a minor allele frequency higher than 1% is represented by the green circles. SSD, sterol sensing domain