Faivre Laurence, Gosset Philippe, Cormier-Daire Valérie, Odent Sylvie, Amiel Jeanne, Giurgea Irina, Nassogne Marie-Cécile, Pasquier Laurent, Munnich Arnold, Romana Serge, Prieur Marguerite, Vekemans Michel, De Blois Marie-Christine, Turleau Catherine
Département de Génétique, Hôpital Necker-Enfants Malades, Paris, France.
Eur J Hum Genet. 2002 Nov;10(11):699-706. doi: 10.1038/sj.ejhg.5200879.
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.
