Occipitoatlantal instability in a child with Kniest syndrome.

A case report of occipitoatlantal instability in a 3-year-5-month-old child with Kniest syndrome is presented. Upper cervical spine instability has not previously been reported in Kniest syndrome. Presenting symptoms are similar to those of atlantoaxial instability, which has been reported in patients with skeletal dysplasia. Our patient was effectively treated with occipito-C2 fusion and halo cast immobilization.