X-linked (recessive) hypomaturation amelogenesis imperfecta: a prosthodontic, genetic, and histopathologic report.

A 16-year-old white girl requested esthetic restorations for her teeth. She was a manifesting heterozygote for the X-linked recessive form of amelogenesis imperfecta with hypomaturation defect. Lyonization theory states that in the somatic cells of female mammals, one of the two X chromosomes is randomly inactivated early in development. Therefore, females who are heterozygous for a given X-linked gene will be mosaic with varying proportions of cells in which only one of a particular pair of alleles is active. This mosaicism produced by lyonization ensures considerable phenotypic variability in the clinical expression of X-linked disorders. Histologic examination of the patient's extracted third molars demonstrated the expected lyonization effect. The patient received six porcelain laminate veneered crowns to restore her maxillary incisor and canine teeth. This article represents the first reported use of such restorations to alleviate the cosmetic and functional handicaps that accompany this genetic disease.