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Cytogenetic diagnosis of “normal 46,XX” karyotypes in spontaneous abortions frequently may be misleading

1999; Elsevier BV; Volume: 71; Issue: 2 Linguagem: Inglês

10.1016/s0015-0282(98)00445-2

1556-5653

Karen A. Bell, Peter G. Van Deerlin, Bassem R. Haddad, Ronald F. Feinberg,

Genetic Syndromes and Imprinting

Objective: To use the molecular identification of Y chromosome material in products of conception cytogenetically diagnosed as "46,XX" to confirm the occurrence of inaccurate cytogenetic test results most likely attributable to maternal cell contamination.Design: Retrospective analysis.Setting: Academic medical center.Patient(s): Thirty-four archival tissues from cases of spontaneous abortion with a "46,XX" karyotype based on cytogenetic analysis.Intervention(s): Maternal and villus DNA were extracted from microdissected, formalin-fixed, paraffin-embedded archival tissues. The presence of the X and Y chromosomes was detected with the use of polymerase chain reaction assays and confirmed with fluorescence in situ hybridization.Main Outcome Measure(s): Accuracy of cytogenetic evaluation of products of conception.Result(s): Four (29%) of 14 first trimester and 1 (5%) of 20 second trimester "46,XX" pregnancy losses contained Y chromosome–specific DNA and demonstrated a single X chromosome–specific allele by polymerase chain reaction analysis consistent with an "XY" karyotype. Fluorescence in situ hybridization was confirmatory in 4 of 5 samples that demonstrated single X and Y signals in villus cells.Conclusion(s): Inaccuracy exists in the cytogenetic analysis of early products of conception that most likely is due to maternal cell contamination. In the absence of confirmatory testing, such as with a "DNA fingerprinting" assay, reports of a "46,XX" karyotype should be used cautiously in patient counseling and management.