What condition is characterized by "without cartilage formation" and causes dwarfism?

The condition characterized by "without cartilage formation" and which causes dwarfism is called achondroplasia. This genetic disorder specifically affects bone growth, leading to disproportionate short stature. Individuals with achondroplasia have a mutation in the fibroblast growth factor receptor 3 (FGFR3) gene, which regulates bone and brain development and is essential for the proper formation of cartilage during the growth process.

In achondroplasia, the growth of long bones is impaired due to this abnormal cartilage formation, which leads to shortened limbs while other parts of the body, such as the trunk, achieve normal length. This disproportionate effect is what classifies the condition and contributes to the characteristic features of dwarfism, including a larger head relative to the body and shorter stature.

Other conditions listed, such as ankylosis, arthritis, and arthrochondritis, do not specifically relate to the absence of cartilage formation linked directly to dwarfism. Ankylosis refers to abnormal stiffness or fusion of joints, arthritis involves inflammation of the joints, and arthrochondritis relates to arthritis with cartilage inflammation. None of these conditions entail the genetic mutation or mechanism that directly results in the characteristic skeletal changes seen in achondroplasia.