Fs. Grass et al., Novel ring chromosome composed of X- and Y-derived material in a girl withmanifestations of Ullrich-Turner syndrome, AM J MED G, 93(5), 2000, pp. 343-348
We present a female infant who has a novel genetic variant of Ullrich-Turne
r syndrome. Chromosome analysis on amniotic fluid cells obtained because of
ultrasound observation of nuchal thickening showed 45,X in all cells. The
infant was born with a low posterior hairline and moderate edema over hands
and feet. Postnatal chromosome analysis demonstrated two cell lines-47% of
the metaphases were 45,X, but 53% had a ring chromosome in addition to the
normal X, FISH studies using alpha satellite probes, an X-whole-chromosome
-paint (WCP) probe, and a Y-cocktail probe determined that the ring was com
posed of both X and Y sequences. FISH studies also determined that the KAL
locus was present on the ring, but that XIST was absent. PCR-based analysis
of lymphocyte DNA documented that the ring contained sequences from both t
he short and the long arm of the Y chromosome. X-chromosome analysis using
a panel of highly polymorphic markers indicated that the ring contained mat
erial derived only from Xp22.1 to Xp21.3, No Xq material was identified on
the ring, and androgen receptor-based X-inactivation studies suggested that
the intact X chromosome was not subject to random X inactivation. (C) 2000
Wiley-Liss, Inc.