What distinguishes Achondroplasia from Hypochondroplasia?

Achondroplasia and hypochondroplasia are both forms of skeletal dysplasia, characterized by disproportionate short stature, but they have distinct clinical features that allow for differentiation between the two.

The presence of obstructive sleep apnea is considered a relevant clinical feature in individuals with achondroplasia. This condition is associated with various anatomical variations, such as a larger head size, which can lead to airway compromise during sleep. Individuals with achondroplasia may exhibit other health considerations related to their skeletal features and obesity, which can further predispose them to sleep apnea. In contrast, this condition is not as commonly reported or noted in hypochondroplasia.

Normal intelligence applies to both conditions, as neither inherently affects cognitive function. Therefore, this characteristic does not serve as a distinguishing factor.

Severe craniofacial dysmorphisms tend to be more pronounced in achondroplasia, but hypochondroplasia may also present some degree of craniofacial differences. Thus, while craniofacial features may vary, they are not definitive methods to distinguish between the two.

Complete lethality in homozygous cases is relevant to achondroplasia, as homozygous individuals typically do not survive to term due to severe complications. However, hypochondroplasia