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Skeletal Radiol (2015) 44:441445 DOI 10.1007/s00256-014-1983-6
CASE REPORT
FGFR3-related condition: a skeletal dysplasia with similarities to thanatophoric dysplasia and SADDAN due to Lys650Met
Shannon G. Farmakis & Marwan Shinawi &
Michelle Miller-Thomas & Alireza Radmanesh &
Thomas E. Herman
Received: 26 June 2014 /Revised: 28 July 2014 /Accepted: 4 August 2014 /Published online: 15 August 2014 # ISS 2014
Abstract Mutations in the fibroblast growth factor receptor 3 (FGFR3) gene account for six related skeletal dysplasia conditions: achondroplasia, hypochondroplasia, thanatophoric dysplasia types 1 and 2, SADDAN (severe achondroplasia with developmental delay and acanthosis nigricans), and platyspondylic lethal skeletal dysplasia, San Diego type. This group of disorders has very characteristic clinical and radiologic features, which distinguish them from other skeletal dysplasias. They display a spectrum of severity in the skeletal findings, ranging from relatively mild hypochondroplasia to lethal thanatophoric dysplasia. We report a patient who has the missense FGFR3 mutation, Lys650Met, previously reported in association only with SADDAN, who exhibits some findings similar to both thanatophoric dysplasia (types 1 and 2) in addition to those findings characteristic of SADDAN.
Keywords SADDAN . Thanatophoric dysplasia . FGFR3 .
Skeletal dysplasia
Introduction
Various mutations in the FGFR3 gene are responsible for achondroplasia, hypochondroplasia, thanatophoric dysplasia types 1 and 2 (TD1 and TD2), SADDAN, and platyspondylic lethal skeletal dysplasia, San Diego type [1]. The Lys650Met mutation is associated with specific phenotypic and radio-graphic findings of SADDAN [24]. Here, we report an interesting patient who has the Lys650Met mutation but has some findings that are typically seen in thanatophoric dysplasia, expanding the spectrum of findings that may be associated with this specific mutation.
Case report
An 8-month-old girl born via caesarean section at 38 weeks gestational age to a G1P1 29-year-old mother and a 30-year-old father was prenatally diagnosed with achondroplasia. Her postnatal course was initially unremarkable; however, she required intubation at 8 days of life due to increasing respiratory distress. She was transferred for further management to another facility where she underwent an initial genetic evaluation, which was negative for the two achondroplasia mutations and 13 common mutations for TD1and TD2. A tracheostomy and gastrostomy were performed at the other hospital. Because of further respiratory decompensation, the patient was transferred to our facility at 2 months of age. On...