Here, we have mapped autosomal dominant cataract segregating in a Caucasian-American family to chromosome 19q, identified a recurrent mutation in the iron response element (IRE) of the gene for ferritin light chain or L-ferritin (FTL), localized expression of FTL in the lens, and evaluated sequence variation of the FTL-IRE region in a case-control cohort of age-related cataract. The gene discussed is FTL; the disease is autosomal dominant cataract.