Prenatal overgrowth and mosaic trisomy 15q25-qter including the IGF1 receptor gene.
Overgrowth is rarely associated with chromosomal imbalances. Here, we report on a male foetus presenting with overgrowth and additional material on the short arm of one of the chromosome 15 in 12% of lymphocytes and 50% of amniotic cells. Parents' karyotypes were normal, indicating a de novo origin for this unbalanced rearrangement. Complementary studies using cytogenetic and FISH studies showed that this additional material resulted in a 15q25-qter trisomy and confirmed the presence of three copies of the insulin-like growth factor 1 receptor (IGF1R) gene, included in the trisomic region. Autopsy performed after termination of pregnancy revealed isolated overgrowth and absence of visceral malformations. The possible mechanisms and origins for the formation of this mosaic pure trisomy are complex. The present observation emphasises the hypothesis that the overgrowth phenotype, frequently reported in patients with trisomy including the 15q26 region, might be causally related to a dosage effect of the IGF1R gene, as well as the importance of chromosome analysis in patients with overgrowth. It also confirms that the overgrowth is of prenatal onset in those observations.
Faivre
Laurence
L
Centre de Génétique Médicale, Hôpital d'Enfants, Dijon, France. laurence.faivre@chu-dijon.fr
Rousseau
Thierry
T
Laurent
Nicole
N
Gosset
Philippe
P
Sanlaville
Damien
D
Thauvin-Robinet
Christel
C
Cusin
Véronica
V
Lionnais
Stéphanie
S
Callier
Patrick
P
Khau Van Kien
Philippe
P
Huet
Frédéric
F
Turleau
Catherine
C
Sagot
Paul
P
Mugneret
Francine
F
D000028:Abortion, Induced; D000328:Adult; D002884:Chromosomes, Human, Pair 15; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008423:Maternal Age; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D018566:Pregnancy, High-Risk; D011296:Prenatal Diagnosis; D017526:Receptor, IGF Type 1 / Q000235:genetics*; D014314:Trisomy / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology
D017526:Receptor, IGF Type 1