Mutation analysis of the FGFR3 gene in a patient with Crouzon syndrome complicated by acanthosis nigricans

Abstract

A 7-year-old female patient presented with frontal bossing and exophthalmos compli-cated by skin pigmentation all over the body for 7 years. Pigmentation was seen on the flexor aspects of the bilateral elbows 1 week after birth, and skin pigmentation gradually appeared at multiple body sites 1 year later. She had suffered from lacrimal duct obstruction since childhood, and repeated dredging of the duct was ineffective. Parents of the child were healthy and non-consanguineous marriage, and had no family history of the same disease. Physical examination showed square-shaped skull, frontal bossing, maxillary hypoplasia, mandibular prognathism, exophthalmos, ocular hypertelorism, depressed nasal bridge, dental malocclusion, and irregular dentition. Skin examination showed dark brown skin all over the body, coarse skin on the neck, axillary and inguinal regions, papillomatous cutaneous thickening, with velvet-like appearance. The patient was diagnosed with Crouzon syndrome complicated by acanthosis nigricans (CAN) . Polymerase chain reaction (PCR) and DNA sequencing were performed to detect mutations in the FGFR3 gene in the patient with CAN, her parents and 100 unrelated healthy controls. A heterozygous missense mutation (C.1172 C > A) was identified in the FGFR3 gene in the proband, but not in her parents or the 100 unrelated healthy controls. The missense mutation in the FGFR3 gene may be a causative mutation leading to the clinical manifestations of the patient. Key words: Acanthosis nigricans; Craniofacial dysostosis; Fibroblast growth factor, type 3; Mutation, missense