Mutations in both proteins cause lens cataract and careful consideration of the detail of these cataract phenotypes alerts us to several interesting features concerning the function of filensin (BFSP1) and CP49 (BFSP2) in the lens.
This further increases the genetic heterogeneity of inherited cataracts and provides clues as to the importance of BFSP1 in the cell biology of intermediate filaments and their role in the eye lens.