Overgrowth and trisomy 15q26.1-qter including the IGF1 receptor gene: report of two families and review of the literature.
Overgrowth is rarely associated with chromosomal imbalances. Here we report on four children from two unrelated families presenting with overgrowth and a terminal duplication of the long arm of chromosome 15 diagnosed using cytogenetic and FISH studies. In both cases, chromosome analysis of the parents showed a balanced translocation involving 15q26.1-qter. Molecular and cytogenetic studies showed three copies of the insulin-like growth factor 1 receptor (IGF1R) gene. This finding suggests that overgrowth observed in our patients might be causally related to a dosage effect of the IGF1R gene, in contrast to severe growth retardation observed in patients with terminal deletion of 15q. The present observation emphasises the importance of chromosome analysis in patients with overgrowth and mental retardation. Moreover, it further delineates a specific phenotype related to trisomy 15q26.1-qter with macrosomia at birth, overgrowth, macrocephaly and mild developmental delay being the major clinical features.
Faivre
Laurence
L
Département de Génétique, Hôpital Necker-Enfants Malades, Paris, France.
Gosset
Philippe
P
Cormier-Daire
Valérie
V
Odent
Sylvie
S
Amiel
Jeanne
J
Giurgea
Irina
I
Nassogne
Marie-Cécile
MC
Pasquier
Laurent
L
Munnich
Arnold
A
Romana
Serge
S
Prieur
Marguerite
M
Vekemans
Michel
M
De Blois
Marie-Christine
MC
Turleau
Catherine
C
D000015:Abnormalities, Multiple / Q000235:genetics; D002884:Chromosomes, Human, Pair 15; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D010375:Pedigree; D017526:Receptor, IGF Type 1 / Q000235:genetics*; D014178:Translocation, Genetic; D014314:Trisomy
D017526:Receptor, IGF Type 1