Figure 3. Gene structure of human BBS4. A: Exon-intron structure of BBS4. Exons are indicated as black boxes. The single missense mutation identified is located in the fifth exon (p.E85Q, red arrow). B: Sequence traces of wild-type and affected family members. A homozygous mutation from G to C was identified in affected member KKESH205#7 (red arrow). C: Amino acid alignment of a portion of the predicted BBS4 protein from nine different vertebrate species. The mutated amino acid is indicated (p.E85Q, red arrow).