FGFR3 and acanthosis nigricans: Patients with activating FGFR3 mutations exhibit skeletal dysplasia characterized by short-limbed dwarfism including achondroplasia (ACH), hypochondroplasia, thanatophoric dysplasia I/II, Muenke syndrome, Crouzon syndrome with acanthosis nigricans, severe ACH with developmental delay and acanthosis nigricans (SADDAN) and lacrimo-auriculo-dental-digital (LADD) syndrome 4,6-8.