A toxic brain disorder occurring in infants, due to accumulation in the gall bladder of bilirubin, a red breakdown product of hemoglobin. The condition is often associated with jaundice, and in some cases is due to blood incompatibility between mother and child.Several types of blood incompatibility have been found to produce excessive bilirubin in the blood of infants, including a small percentage of Rh-positive children with Rh-negative mothers. The condition may also be associated with prematurity or with severe neonatal sepsis (blood poisoning). The result is an acute disease in the newborn child termed kernicterus, which is characterized by jaundice, anemia, a high-pitched cry, drowsiness, and unstable body temperature. A yellow staining occurs in structures at the base of the brain, particularly the basal ganglia, cerebellum, and hippocampus, with destruction of cells in severe cases. If the condition is not arrested it may lead to paralysis, convulsions, spasticity, deafness, and mental retardation.The disorder, however, can be detected a few days after birth, and the danger of brain damage virtually eliminated by exchange blood transfusions. In addition, an effective preventive procedure has been recently developed. After the birth of her first child, the mother can be injected with a serum prepared by injection of laboratory animals with Rh cells. This serum contains an antibody which renders harmless the blood cells of the child that have leaked across the placental membranes during pregnancy and delivery— cells which would otherwise have initiated the production of maternal antibodies harmful to succeeding babies. In cases where the mother has not been treated with the anti-Rh serum, the treatment of choice for a jaundiced offspring is still exchange transfusions, which can now be performed while the child is still in the uterus, as well as after birth. See MENTAL RETARDATION (CAUSES).