RAPID COMMUNICATION Monoclonal Nature of Transient Abnormal Myelopoiesis in Down’s Syndrome

Neonates with Down’s syndrome occasionally show an excess of blasts in their peripheral blood. This disorder spontaneously resolves within several months and is called transient abnormal myelopoiesis (TAM) or transient myeloproliferative disorder. It has been uncertain whether the excess of blasts in TAM is a result of a clonal proliferation or a polyclonal reactive condition. The clonality of cells in females can be examined by analysis of the methylation patterns of the X chromosomes of proliferating cells using restriction fragment length polymorphism (RFLP). Using this strategy, we studied three females with Down’s syndrome accompa-

[1]  M. A. Goldman,et al.  Mammalian X chromosome inactivation. , 1992, Molecular genetic medicine.

[2]  Y. Hayashi,et al.  Ultrastructural and ultracytochemical differences between transient myeloproliferative disorder and megakaryoblastic leukaemia in Down's syndrome , 1989, British journal of haematology.

[3]  M. Eguchi,et al.  Cytogenetic findings and clinical features in acute leukemia and transient myeloproliferative disorder in Down's syndrome. , 1988, Blood.

[4]  H. Willard,et al.  Clonal analysis using recombinant DNA probes from the X-chromosome. , 1987, Cancer research.

[5]  T. Suda,et al.  Differentiation of blast cells from a Down's syndrome patient with transient myeloproliferative disorder. , 1987, Blood.

[6]  A. Zipursky,et al.  Megakaryoblastic leukemia and Down's syndrome: a review. , 1987, Pediatric hematology and oncology.

[7]  A. Riggs,et al.  Active X chromosome DNA is unmethylated at eight CCGG sites clustered in a guanine-plus-cytosine-rich island at the 5' end of the gene for phosphoglycerate kinase , 1986, Molecular and cellular biology.

[8]  A. Feinberg,et al.  Use of restriction fragment length polymorphisms to determine the clonal origin of human tumors. , 1985, Science.

[9]  B. Migeon,et al.  Methylation of the hypoxanthine phosphoribosyltransferase locus on the human X chromosome: implications for X-chromosome inactivation. , 1984, Proceedings of the National Academy of Sciences of the United States of America.

[10]  A. C. Chinault,et al.  Differential methylation of hypoxanthine phosphoribosyltransferase genes on active and inactive human X chromosomes. , 1984, Proceedings of the National Academy of Sciences of the United States of America.

[11]  T. Friedmann,et al.  Isolation of a genomic clone partially encoding human hypoxanthine phosphoribosyltransferase. , 1982, Proceedings of the National Academy of Sciences of the United States of America.