Partial deletion of a group-F (19-20) chromosome in a physically handicapped psychiatric male patient.

Among autosome abnormalities, those involving group-F (19-20) chromosomes are seldom encountered. Even in abortuses where chromosome defects, namely trisomies, are more frequent than in live births, Carr (1969) stated that group-F chromosomes anomalies are relatively rare. The previous cytogenetic studies involving group-F autosomes concerned only patients with haematological diseases. Borges, Wald, and Hoffman (1964) while studying a large family harboring the gene for congenital nonspherocytic haemolytic anaemia of the glucose-6-phosphate dehydrogenase variety (CNSHA) noted that two boys and their maternal grandfather, all with CNSHA, showed mosaicism with the minor (10 to 15%) cell population lacking one F group chromosome. The boys' parents and one normal brother showed no mosaicism. Kiossoglou, Mitus, and Dameshek (1965) reported a deleted group-F chromosome present in 6 of 7 cells karyotyped in a patient with acute granulocytic leukaemia. Kay, Lawler, and Millard (1966) described 4 cases of polycythaemia vera treated by radio-phosphorus in whom a small F chromosome was found in the bone marrow. Millard et al (1968) made further observations of a similar finding in three more patients with polycythaemia vera, two ofthem had received 32P and one busulphan only. Group-F chromosome anamolies were found also in 5 out of 6 patients with idiopathic sideroblastic anaemia (de Grouchy et al, 1966), 2 of whom had a partially deleted group-F chromosome and the 3 others a probable pericentric inversion of the same autosome. Goodman et al (1968) noted a small group-F chromosome in conjunction with a ring chromosome in a 79-year-old female patient who had myelofibrosis secondary to polycythaemia vera. Following a pretreatment cytogenetic study of a 25-year-old male with chronic myeloid leukae-