Deletion (X)(q26.1-->q28) in a proband and her mother: molecular characterization and phenotypic-karyotypic deductions.
During a routine prenatal diagnosis we detected a female fetus with an apparent terminal deletion of an X chromosome with a karyotype 46,X,del(X)(q25); the mother, who later underwent premature ovarian failure, had the same Xq deletion. To further delineate this familial X deletion and to determine whether the deletion was truly terminal or, rather, interstitial (retaining a portion of the terminal Xq28), we used a combination of fluorescence in situ hybridization (FISH) and Southern analyses. RFLP analyses and dosage estimation by densitometry were performed with a panel of nine probes (DXS3, DXS17, DXS11, DXS42, DXS86, DXS144E, DXS105, DXS304, and DXS52) that span the region Xq21 to subtelomeric Xq28. We detected a deletion involving the five probes spanning Xq26-Xq28. FISH with a cosmid probe (CLH 128) that defined Xq28 provided further evidence of a deletion in that region. Analysis with the X chromosome-specific cocktail probes spanning Xpter-qter showed hybridization signal all along the abnormal X, excluding the possibility of a cryptic translocation. However, sequential FISH with the X alpha-satellite probe DXZ1 and a probe for total human telomeres showed the presence of telomeres on both the normal and deleted X chromosomes. From the molecular and FISH analyses we interpret the deletion in this family as 46,X,del(X) (pter-->q26::qter). In light of previous phenotypic-karyotypic correlations, it can be deduced that this region contains a locus responsible for ovarian maintenance.
Tharapel
A T
AT
Department of Pediatrics, University of Tennessee, Memphis 38163.
Anderson
K P
KP
Simpson
J L
JL
Martens
P R
PR
Wilroy
R S
RS
Llerena
J C
JC
Schwartz
C E
CE
D000328:Adult; D000649:Amniocentesis; D015139:Blotting, Southern; D002648:Child; D002871:Chromosome Banding; D002872:Chromosome Deletion; D015342:DNA Probes; D005260:Female; D005333:Fetus / Q000502:physiology; D006720:Homozygote; D006801:Humans; D017403:In Situ Hybridization; D007621:Karyotyping; D008297:Male; D010641:Phenotype; D012150:Polymorphism, Restriction Fragment Length; D011247:Pregnancy; D016649:Primary Ovarian Insufficiency / Q000235:genetics; D015183:Restriction Mapping; D016615:Telomere / Q000648:ultrastructure; D014960:X Chromosome
D015342:DNA Probes