BOS is characterized by severe growth deficits, dietary problems, severe developmental delays and retardation, typical facial features, microcephaly, hirsutism of the forehead, cleft lip palate, retinal changes, flexion anomalies affecting the upper extremities with dislocation of the radial head and ulnar deviation of the fingers, changes affecting the lower extremities, structural brain changes, cramping seizures, and other anomalies. Approximately 40% of patients die during early infancy, usually due to bradycardia, obstructive apnea, or pulmonary infections. In those that survive, the characteristic facial features may subside with time. Girls are affected more frequently than boys. There is presumably an increased risk of developing Wilms tumors.