Final answer:
Morquio syndrome is the mucopolysaccharidosis associated with the highest rate of odontoid hypoplasia and atlantoaxial instability.
Step-by-step explanation:
The mucopolysaccharidosis associated with the highest rate of odontoid hypoplasia and atlantoaxial instability is Morquio syndrome.
Mucopolysaccharidoses (MPS) are a group of inherited disorders characterized by the accumulation of glycosaminoglycans (GAGs) in various tissues. Morquio syndrome, also known as MPS IV, is caused by a deficiency of the enzymes responsible for breaking down keratan sulfate, a type of GAG. This leads to skeletal abnormalities, including odontoid hypoplasia and atlantoaxial instability, which can affect movement and cause neurological complications.
Other types of mucopolysaccharidoses, such as Hunter syndrome and Hurler syndrome, may also cause skeletal abnormalities, but Morquio syndrome is specifically associated with the highest rate of odontoid hypoplasia and atlantoaxial instability.