A Case of Achondroplasia Associated with Cervicomedullary-Junction Compression

Achondroplasia is the most common skeletal dysplasia and is caused by defective fibroblast growth factor receptor (FGFR) 3 in endochondral chondrocytes. Children with achondroplasia may have high cervical myelopathy due to stenosis of the craniocervical junction and an increased risk of sudden death. We report a female patient with achondroplasia who required surgical decompression at the age of 13 mo. The female patient was diagnosed with achondroplasia clinically, radiologically and genetically shortly after birth. The newborn period was uneventful. She developed head control at the age of 6 mo, but she could not sit by the age of 12 mo. At the age of 8 mo, her parents noticed her eyes did not close and a diagnosis of left peripheral nerve palsy was made. Occasional hyperextension of the trunk was observed. There was also minimal asymmetry of voluntary leg movement and bilateral ankle clonus. By these findings craniocervical junction compression was strongly suspected. MRI examination revealed compression at the craniocervical junction by the occipital bone and myleomalacia. The patient underwent suboccipital decompressive surgery at the age of 13 mo. Recovery after surgery was uneventful, and although her left facial nerve palsy did not improve, gross motor function had improved by the age of 2 yr. The patient is now cognitive and neurologically normal at the age of 3 yr. Infants with achondroplasia are at risk of lethal sequelae of craniocervical junction abnormalities, so careful neurological assessment and early MRI examination is recommended.