De novo monosomy 9p24.3-pter and trisomy 17q24.3-qter characterised by microarray comparative genomic hybridisation in a fetus with an increased nuchal translucency.
OBJECTIVE
Increased nuchal translucency (NT) during the first trimester of pregnancy is a useful marker to detect chromosomal abnormalities. Here, we report a prenatal case with molecular cytogenetic characterisation of an abnormal derivative chromosome 9 identified through NT.


METHODS
Amniocentesis was performed because of an increased NT (4.4 mm) and showed an abnormal de novo 46,XX,add(9)(p24.3) karyotype. To characterise the origin of the small additional material on 9p, we performed a microarray comparative genomic hybridisation (microarray CGH) using a genomic DNA array providing an average of 1 Mb resolution.


RESULTS
Microarray CGH showed a deletion of distal 9p and a trisomy of distal 17q. These results were confirmed by FISH analyses. Microarray CGH provided accurate information on the breakpoint regions and the size of both distal 9p deletion and distal 17q trisomy. The fetus was therefore a carrier of a de novo derivative chromosome 9 arising from a t(9;17)(p24.3;q24.3) translocation and generating a monosomy 9p24.3-pter and a trisomy 17q24.3-qter.


CONCLUSIONS
This case illustrates that microarray CGH is a rapid, powerful and sensitive technology to identify small de novo unbalanced chromosomal abnormalities and can be applied in prenatal diagnosis.
Brisset
Sophie
S
Service de Génétique et Reproduction (APHP), Hôpital Antoine Béclère, Clamart, France.
Kasakyan
Serdar
S
L'Herminé
Aurore Coulomb
AC
Mairovitz
Valérie
V
Gautier
Evelyne
E
Aubry
Marie-Cécile
MC
Benkhalifa
Moncef
M
Tachdjian
Gérard
G
D000015:Abnormalities, Multiple / Q000175:diagnosis; D000328:Adult; D025063:Chromosome Disorders / Q000175:diagnosis*; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics*; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D009006:Monosomy / Q000175:diagnosis*; D048208:Nuchal Translucency Measurement; D009693:Nucleic Acid Hybridization / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis; D014178:Translocation, Genetic; D014314:Trisomy / Q000175:diagnosis*