Molecular cytogenetic analysis of a duplication Xp in a female with an abnormal phenotype and random X inactivation.
We describe a female infant with severe abnormal phenotype with a de novo partial duplication of the short arm of the X chromosome. Chromosome painting confirmed the origin of this X duplication. Molecular cytogenetic analysis with fluorescence in situ hybridization (FISH) was performed with YAC probes, further delineating the breakpoints. The karyotype was 46, X dup(X)(p11-p21.2). Cytogenetic replication studies showed that the normal and duplicated X chromosomes were randomly inactivated in lymphocytes. In most females with structurally abnormal X chromosomes, the abnormal chromosome is inactivated and they are phenotypically apparently normal relatives of phenotypically abnormal males having dupX. Therefore, in this case, there is functional disomy of Xp11-p21.2 in the cells with an active dup(X), most likely resulting in abnormal clinical findings in the patient.
Portnoï
M F
MF
Laboratoire de Cytogénétique, Hopital Saint-Antoine, Paris, France.
Bouayed-Abdelmoula
N
N
Mirc
M
M
Zemni
R
R
Castaing
H
H
Stephann
J
J
Ardalan
A
A
Vialard
F
F
Nouchy
M
M
Daoud
P
P
Chelly
J
J
Taillemite
J L
JL
D000328:Adult; D020732:Cytogenetic Analysis / Q000379:methods*; D004303:Dosage Compensation, Genetic; D005260:Female; D020440:Gene Duplication; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011247:Pregnancy; D011248:Pregnancy Complications; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D014960:X Chromosome / Q000235:genetics*