Symptoms in small babies include hypotonia (floppiness) and low muscle tone. As the muscles are weak and immobile, contractures (tightness) in the hip, ankle, knee and elbow joints are common. In children that do not have contractures, initial problems may be difficulties holding the head, and delays in sitting and walking.
Some forms of CMDs can have associated brain changes on a magnetic resonance imaging (MRI) scan. The pattern of these brain MRI changes helps to identify the subtype of CMD. Some, but not all children with CMD and brain changes visible on an MRI scan, may have learning difficulties (see entry Learning Disability) with or without epileptic seizures (see entry Epilepsy). Learning difficulties can be mild, moderate or severe and do not get worse over time.