FGFR3 Disorders: Thanatophoric Dysplasia, Achondroplasia, and Hypochondroplasia

Abstract Fibroblast growth factor receptor 3 (FGFR3) disorders are a group of disorders that include thanatophoric dysplasia, achondroplasia, and hypochondroplasia. Achondroplasia is the most frequent cause of nonlethal dwarfism and is characterized by relative macrocephaly, characteristic facies, shortened long bones, relative long trunk and a distinct form of brachydactyly associated with a trident configuration to the hand. Many of these findings can be detected by prenatal ultrasound. Thanatophoric dysplasia is one of the most common lethal skeletal disorders and is associated with relative macrocephaly, frontal bossing, severe micromelia, and small, lethal appearing thorax. Achondroplasia and thanatophoric dysplasia are inherited as autosomal dominant disorders due to heterozygosity for mutations in FGFR3 .