This paper describes the clinical, histological and genetic findings in individuals with amelogenesis imperfecta diagnosed in more than 50 families in the county of Västerbotten, northern Sweden. Using pedigree analysis, families with autosomal and X-linked inheritance as well as sporadic cases of amelogenesis imperfecta have been recognized. A clinical subclassification in eight different variants of amelogenesis imperfecta has been made. The gene defects have been identified for two of these variants and the chromosomal location has been established for a third variant.