Children with Down’s syndrome have multiple malformations due to presence of extra genetic material from chromosome 21. An ongoing assessment and management should be performed throughout childhood for specific morbidities. Early identification of these potential risks may maintain or even improve their level of functioning as well as to facilitate transition to adulthood.

Atlantoaxial instability is one of these areas of concerns. The incidence of instability ranges from 10% to 25%. Screening for atlantoaxial instability requires regular assessment for those individuals participating in sports.

Atlantoaxial instability, also called atlantoaxial subluxation, refers to increased mobility at the atlantoaxial joint between the first and second cervical vertebrae. The etiology of atlantoaxial instability is not well understood nor is it unique to Down’s syndrome. Atlantoaxial instability may include abnormalities of the ligaments or bony structures of C1 and C2.

Almost all of the patients are affected by atlantoaxial instability are asymptomatic. Patients who are symptomatic may exhibit neurologic signs and symptoms associated with upper motor or posterior column lesions such as easy fatigability, difficulty walking, abnormal gait, neck pain, limited neck mobility, incontinence, torticollis, incoordination, sensory deficits, spasticity, hyperreflexia, and clonus.