Which condition is the most common skeletal dysplasia?

Which condition is the most common skeletal dysplasia?

• A. Achondroplasia
• B. Osteogenesis imperfecta
• C. Thanatophoric dysplasia
• D. Pseudoachondroplasia

Answer: (A)

Achondroplasia is the most common skeletal dysplasia. It accounts for the majority of disproportionate dwarfism cases and is most often caused by a de novo FGFR3 mutation (though it can be inherited in an autosomal dominant pattern). The hallmark features seen on imaging and ultrasound are rhizomelic shortening of the proximal limbs (short upper arms and thighs) with a relatively normal trunk length, along with macrocephaly with frontal bossing and midface hypoplasia. In prenatal imaging, long bones appear shortened while the torso remains comparatively normal in size. These typical findings, plus its high frequency relative to other dysplasias, explain why this condition is identified as the most common skeletal dysplasia.

Achondroplasia is the most common skeletal dysplasia. It accounts for the majority of disproportionate dwarfism cases and is most often caused by a de novo FGFR3 mutation (though it can be inherited in an autosomal dominant pattern). The hallmark features seen on imaging and ultrasound are rhizomelic shortening of the proximal limbs (short upper arms and thighs) with a relatively normal trunk length, along with macrocephaly with frontal bossing and midface hypoplasia. In prenatal imaging, long bones appear shortened while the torso remains comparatively normal in size. These typical findings, plus its high frequency relative to other dysplasias, explain why this condition is identified as the most common skeletal dysplasia.