Cytogenetic Studies of a Patient with Chronic Myelocytic Leukemia and his Nonleukemic Identical Twin

Abstract

One of our patients with chronic myelocytic leukemia has a twin brother. The twins, 31 years old, show similar physical appearance. Both have blue eyes, brown hair and are right-handed. Anthropometric measurements and fingerprint patterns are matching. Blood group antigens, serum factors and PTC tasting are identical. Blood group antigens of the parents have also been determined. It has been calculated that the probability that the twins are MZ is higher than 99.8%.The twins were the result of an uncomplicated pregnancy. There are no other siblings. No family history of consanguinity, hematological disorders or cancer was given. They spent their childhood on a farm. Both have not been exposed to drugs, benzene or radiological procedures, apart from routine X-ray films of the chest.Our patient, who is still working on his farm, had been referred to a hospital in June 1959, because of a knife wound of the chest with a myocardial laceration and pericardial tamponade. White blood cell count at that time was 22300 with 3% basophils.In April 1962, the diagnosis of chronic myelocytic leukemia was established. Findings included hepatosplenomegaly, leukocytosis with a marked shift to the left, hyperplasia of granulopoiesis in the bone marrow and diminished leukocyte alkaline phosphatase activity. In the following years the patient was treated with cyclophosphamide, splenic irradiation and busulfan. Busulfan is continued at present at low doses.