Achondroplasia is the most common genetic cause of disproportionate dwarfism, affecting roughly 1 in 20,000 to 30,000 babies. It is caused by a gene mutation that impairs the conversion of cartilage into bone, resulting in short limbs, an average-sized torso, and a prominent forehead. While often inherited, over 80% of cases are spontaneous mutations in families with average-height parents. Individuals have normal intelligence and can lead full, active lives, though they may face health complications like sleep apnea or spinal issues. 

YouTube source: Medical Centric Podcast