C1-C2 Polyaxial Screw Rod Fixation for Atlantoaxial Dislocation due to Morquios Disease

13 years male born of nonconsanguineous parents presented with progressive spastic weakness of upper and lower limbs with atrophy and contracture of muscles 18 months duration. No specific family history.Sibling was normal.Ophthalmological examination showed bilateral corneal haziness. Skeletal survey showed skeletal dysplasia around joints. These features are consistent with Morquios disease. Atlantoaxial Dislocation due to odontoid hypoplasia was considered to be the cause of quadriparesis. C1- C2 pars screw fixation with bone grafting of the AA joints was done