Functional disomy of the Xq28 chromosome region.
We report on two patients, a boy and a girl, with an additional Xq28 chromosome segment translocated onto the long arm of an autosome. The karyotypes were 46,XY,der(10)t(X;10)(q28;qter) and 46,XX,der(4)t(X;4)(q28;q34), respectively. In both cases, the de novo cryptic unbalanced X-autosome translocation resulted in a Xq28 chromosome functional disomy. To our knowledge, at least 17 patients with a distal Xq chromosome functional disomy have been described in the literature. This is the third report of a girl with an unbalanced translocation yielding such a disomy. When the clinical features of both patients are compared to those observed in patients reported in the literature, a distinct phenotype emerges including severe mental retardation, facial dysmorphic features with a wide face, a small mouth and a thin pointed nose, major axial hypotonia, severe feeding problems and proneness to infections. A clinically oriented FISH study using subtelomeric probes is necessary to detect such a cryptic rearrangement.
Sanlaville
Damien
D
Département de Génétique, Hôpital Necker-Enfants Malades, Paris, France. damien.sanlaville@nck.ap-hop-paris.fr
Prieur
Marguerite
M
de Blois
Marie-Christine
MC
Genevieve
David
D
Lapierre
Jean-Michel
JM
Ozilou
Catherine
C
Picq
Monique
M
Gosset
Philippe
P
Morichon-Delvallez
Nicole
N
Munnich
Arnold
A
Cormier-Daire
Valerie
V
Baujat
Genevieve
G
Romana
Serge
S
Vekemans
Michel
M
Turleau
Catherine
C
D000015:Abnormalities, Multiple / Q000235:genetics*; D000782:Aneuploidy; D002879:Chromosomes, Human, Pair 10 / Q000235:genetics*; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D041321:Chromosomes, Human, X / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008297:Male; D014178:Translocation, Genetic