The two most common autosomal dominant dystrophies of the corneal stroma are lattice corneal dystrophy type I and granular dystrophy. A third autosomal dominant stromal dystrophy (Avellino) has also been recognized. Chromosome linkage analysis of four families with Avellino dystrophy mapped the disease-causing gene to chromosome 5q. Subsequent linkage analysis of two families with typical lattice dystrophy and two with typical granular dystrophy also revealed significant linkage with the same markers. Thus, each of three clinically and histopathologically distinct phenotypes is independently linked to 5q. The maximum combined lod score using all 114 affected patients was 28.6 with marker D5S393. None of the 14 known human amyloid-associated genes map to chromosome 5.