The Christchurch Chromosome (Gp–)

Abstract

An 18-month-old male infant with mongolism and erythremic myelosis had two cell lines in his bone marrow and peripheral blood: one cell line, with 47 chromosomes, had 2 Gp— chromosomes, and the other, with 51 chromosomes, had 3 Gp—chromosomes. He died of acute myeloblastic leukemia at 21 months of age. The Gp— chromosome was present in four generations of his family; his mother, his maternal grandmother and his maternal maternal great-grandmother were carriers and phenotypically normal. The Gp— chromosome has not previously been reported in a patient with erythremic myelosis, an uncommon disease in children. Review of all reported propositi and members of their families with the Gp— chromosome shows no consistent phenotypic effect of this deletion. However, among 37 progeny of 18 carriers of the Gp— chromosome, five have had mongolism with 47 chromosomes. The Gp— chromosome itself appears to segregate normally among the progeny of carriers.