Clinical Characteristics

When optimal nutritional intake has been established, most children are happy and smiling. Reflux of food into the esophagus (gastroesophageal reflux) can be very painful and lead to prolonged crying. Clinical malformations usually do not occur. However, there is an increased risk for developing orthopedic abnormalities like scoliosis, dislocation of the hips and shortening of the muscles (contractures). After periods with uncovered needs of energy (catabolic situations) there is an increased risk for development of involuntary and abnormal movements (dystonia, hypertonia / spasticity, athetosis) caused by damage of certain brain areas (basal ganglia).