Novel ring chromosome composed of X- and Y-derived material in a girl with manifestations of Ullrich-Turner syndrome.
We present a female infant who has a novel genetic variant of Ullrich-Turner 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 composed 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 the short and the long arm of the Y chromosome. X-chromosome analysis using a panel of highly polymorphic markers indicated that the ring contained material 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.
Grass
F S
FS
Department of Pediatrics, Carolinas Medical Center, Charlotte, North Carolina, USA.
Brown
C A
CA
Backeljauw
P F
PF
Lucas
A
A
Brasington
C
C
Gazak
J M
JM
Nakano
S
S
Ostrowski
R S
RS
Spence
J E
JE
D004303:Dosage Compensation, Genetic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007231:Infant, Newborn; D012303:Ring Chromosomes; D017422:Sequence Analysis, DNA; D012729:Sex Chromosome Aberrations; D013577:Syndrome; D014960:X Chromosome; D014998:Y Chromosome