Diagnosis of Achondroplasia
Clinical and radiologic features of achondroplasia are well-characterized. Those with typical findings generally do not need molecular genetic testing to confirm the diagnosis. When clinical features raise suspicion in a newborn, X-ray (radiography) findings can be used to help confirm the diagnosis. However, if there is uncertainty, identification of the genetic variant of the FGFR3 gene by molecular genetic testing can be used to establish the diagnosis. Below is a list adapted from Pauli and Legare (2018) that provides clinical signs that may be used in the diagnosis of achondroplasia.

Disproportionate short stature
Macrocephaly with frontal bossing
Backward displacement of the midface and depressed nasal bridge
Shortening of the arms with redundant skin folds on limbs
Limitation of elbow extension
Shortened fingers and toes (brachydactyly)
Trident configuration of the hands
Bow legs
Exaggerated inward curve of the spine (lumbar lordosis)
Joint laxity