Fetoplacental discrepancy involving structural abnormalities of chromosome 8 detected by prenatal diagnosis.
We describe the finding of three cell lines involving different structural abnormalities of chromosome 8 detected in a prenatal diagnosis. Chorionic villi sampling (CVS) was performed on a pregnant woman because of advanced maternal age. Semidirect cytogenetic analysis showed a mos46,XX,i(8q)/46,XX,del(8)(p11.2) karyotype, confirmed by fluorescence in situ hybridization (FISH). Amniocentesis was subsequently performed, and the karyotype obtained was 46,XX,dup(8)(p23p11.2). The pregnancy was terminated; pathologic findings included clubfeet, clenched left hand, subcutaneous edema and bilateral hydrocephalus. Molecular studies using chromosome 8 microsatellites performed on parents' blood and fetal tissues revealed a maternal meiotic origin of the inv dup(8p) with deletion of the distal p23 region and duplication of the remaining 8p. We propose a model to explain the cytogenetic findings, which includes a first maternal meiotic error giving rise to a large dicentric isochromosome 8 present in the ovum, a second error in one of the first zygote divisions with misdivision of the dicentric 8 giving rise to a cell line with del(8p) confined to the trophoblast and another cell line with inv dup(8p) confined to the fetal tissue and a third error in the trophoblast giving rise to a further cell line with isochromosome 8q.
Soler
Anna
A
Servei de Genètica, CDB, Hospital Clínic, Barcelona, Spain. asoler@clinic.ub.es
Sánchez
Aurora
A
Carrió
Ana
A
Badenas
Cèlia
C
Milà
Montserrat
M
Borrell
Antoni
A
D000015:Abnormalities, Multiple / Q000235:genetics*; D000025:Abortion, Eugenic; D000328:Adult; D015193:Chorionic Villi Sampling; D002871:Chromosome Banding; D002872:Chromosome Deletion; D025063:Chromosome Disorders / Q000175:diagnosis*; D007446:Chromosome Inversion; D002898:Chromosomes, Human, Pair 8; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008423:Maternal Age; D018895:Microsatellite Repeats / Q000235:genetics; D008957:Models, Genetic; D009030:Mosaicism / Q000175:diagnosis*; D011247:Pregnancy; D018566:Pregnancy, High-Risk