Figure 3. P protein structure and mutation location.

This figure shows the location of mutations in the human P gene associated with OCA2. The red represents the coding region of the human P gene; the function of the protein is unknown but it is mutated in oculocutaneous albinism (OCA2). The yellow boxes represent the 12 transmembrane regions of the polypeptide. The blue arrows at the top are the locations of missense mutations and the blue arrows at the bottom are the locations of the frameshift and nonsense mutations. The horizontal blue line represents the 2.7 Kb deletion which eliminates exon 7 (54 amino acids) of the P gene, resulting in the formation of a premature stop codon.