Which characteristic is NOT related to Achondroplasia?

Achondroplasia is a common form of skeletal dysplasia and is characterized by a range of specific physical features associated with its genetic basis. Among the key characteristics associated with Achondroplasia are rhizomelic limb shortening, which refers to the disproportionate shortening of the proximal segments of the limbs; mild joint laxity, which can be present but is not a major feature; and brachydactyly, where the fingers and toes are shorter than normal.

Severe polydactyly, the presence of extra fingers or toes, is not a characteristic associated with Achondroplasia. Instead, individuals with Achondroplasia typically have a normal number of digits. The disorder primarily presents with the skeletal features mentioned above, and polydactyly would suggest a different genetic condition or developmental anomaly that is not typical for individuals with Achondroplasia. Thus, the correct identification of severe polydactyly as not related to Achondroplasia underscores the distinctive features that define this condition.