X microchromosome with additional chromosome anomalies found in Ullrich-Turner syndrome.
Using standard cytogenetic methods coupled with molecular techniques, the following karyotype mos 45,X/46,XXq+/46,X+mar (X)/47,XXq+,+mar(X), was identified in a patient with Ullrich-Turner syndrome (UTS). High-resolution banding (n = 650) of the metaphase chromosomes yielded a breakpoint at q28 on the Xq+ rearranged chromosome. FISH was used to determine the presence of Y-containing DNA in the Xq+ and the mar(X) chromosomes. The following molecular probes were used: DYZ1, DYZ3, and spectrum orange WCP Y. The lack of specific hybridization of these probes was interpreted as a low risk of gonadoblastoma in this patient. Using X-chromosome- and centromere-specific probes, FISH demonstrated the presence of hybridizing material on both rearranged chromosomes, the Xq+ and mar(X). Finally, we determined that the mar(X) and Xq+ chromosomes contained telomeres in the absence of any interstitial telomeric hybridizing material. A micro-X chromosome is present in this UTS patient. Delineation of events leading toward the mechanisms responsible for the multiple DNA rearrangements required to generate the micro-X and Xq+ chromosomes awaits future studies.
Wydner
K L
KL
Department of Pediatrics, University of Medicine and Dentistry of New Jersey, New Brunswick, USA.
Li
M
M
Singer-Granick
C
C
Sciorra
L J
LJ
Krueger
L J
LJ
D002503:Centromere / Q000737:chemistry; D002648:Child; D002869:Chromosome Aberrations; D003878:Dermatoglyphics; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008856:Microscopy, Fluorescence; D009030:Mosaicism; D016615:Telomere / Q000737:chemistry; D014424:Turner Syndrome / Q000235:genetics*; D014960:X Chromosome