[Familial myeloproliferative syndrome (study of 4 families and review of the literature)].

The authors describe 4 families whose members showed myeloproliferative diseases. In one of the families, polycythemia vera (PV) was seen in twin brother and sister, in the other one, chronic myeloleukemia (CML) afflicted both daughter and mother, and in the two remaining families PV and CML afflicted two brothers and mother and daughter, respectively. It was established that neutrophil phosphatase activity was lowered not only in the afflicted brother but also in healthy members of the third family. Based on the reported and their own data the authors arrive at the conclusion that familial myeloproliferative diseases occur in rare cases. In all the cases of familial myeloproliferative diseases, the transmission of the illness by heredity was discovered to be impossible. It was also ascertained that transmitted by heredity are only those cell deficiencies of the tissues that later on will be afflicted by leukemia or will develop immunodeficiency manifested by increased mutation of the myelopoietic cells (DNA repair deficiencies) or by inability to eliminate the leukemic cells.