Mongolism with mosaic chromosome pattern

A Mongoloid infant is presented with a mosaic chromosome pattern in both blood and skin. Unusual immune responses were also manifested by a delayed homograft reaction and by little response to infection. Approximately one third of the white blood cells in the mother's peripheral blood belonged to the male type. It is felt that this most likely represents a prenatal transfusion of male cells into the mother's circulation from the twin of the patient here described, but other mechanisms are also considered.