Longitudinal cytogenetic study of metaphase and interphase cells in childhood monosomy 7 syndrome.
A 15-year-old male with myelodysplastic syndrome (MDS) characterized by monosomy 7 was cytogenetically evaluated by metaphase karyotyping and fluorescence in situ hybridization (FISH) of interphase cells at six different points during the course of his disease. At diagnosis, there was complete agreement between metaphase and interphase findings. Interphase analysis alone provided important cytogenetic information on the first specimens received following intensive combination chemotherapy and bone marrow transplantation where metaphase analyses were uninformative. The detection of a minor post-treatment monosomy 7 population by interphase but not metaphase studies may have identified minimal residual disease prior to recurrence of MDS. From this longitudinal study, it is concluded that metaphase and interphase cytogenetic analyses form complementary approaches and that use of both provides greater analytical power when appropriate chromosome markers are available.