Possible gonadal mosaicism in a family with hemoglobin Köln

A brother and sister were the first members of a family to possess hemoglobin Köln (alpha 2 beta 2(98) Val leads to Met). Studies of these siblings and their parents strongly indicated that the anomaly had arisen by spontaneous mutation. Gonadal mosaicism of one of the parents offers the best explanation for the appearance of a spontaneous mutation in multiple members of a sibship.