Mutations in COMP cause pseudoachondroplasia (PSACH), a severe dwarfing condition characterized by disproportionate short stature, short limbs, joint laxity, pain, and early onset joint degeneration [2,9,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38]. The gene discussed is COMP; the disease is pseudoachondroplasia.