This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sho Stature, Subject name: Pediatrics
Upper segment : lower segment ratio decreases in all of the following except? 
Select and explain. 
A. Spondylo epiphyseal dysplasia, B. Alagille syndrome, C. Achondroplasia, D. Pott's disease
C: Achondroplasia
Answer: C: Achondroplasia 
Explanation: Upper segment : lower segment ratio increases in Achondroplasia- cause of sho limb dwarfism. Sho trunk dwarfism (US:LS ratio- decreases) Sho limb dwarfism (US:LS ratio- increases) Sho- Spondyloepiphyseal dysplasia Rickets Man- Mucopolysaccharidosis Achondroplasia May- Mucolipidosis Osteogenesis imperfecta Climb- Caries spine (pott's disease) Congenital hypothyroidism High- Hemiveebra Chondroectodermal dysplasia