title: Imprinted anomalies in fetal and childhood growth disorders: the model of Russell-Silver and Beckwith-Wiedemann syndromes.
abstract: Fetal growth is a complex process. Its restriction is associated with morbidity and long term metabolic consequences. Imprinted genes have a critical role in mammalian fetal growth. The human chromosome 11p15 encompasses two imprinted domains regulated by their own differentially methylated region (DMR), also called Imprinted Control Region (ICR1 at the H19/IGF-2 domain, paternally methylated), and ICR2 at the KCNQ1/CDKN1C domain (maternally methylated). Loss of imprinting at these two domains is implicated in two growth disorders clinically opposite. A loss of DNA methylation (LOM) at ICR1 is identified in over 50% of patients with Russell-Silver syndrome (RSS), characterized by intrauterine and postnatal growth retardation, spared cranial growth, frequent body asymmetry and severe feeding difficulties. Inversely, a gain of methylation at ICR1 is found in 10% of patients with Beckwith-Wiedemann syndrome (BWS), an overgrowth syndrome with an enhanced childhood tumor risk. We have identified over 150 RSS patients with 11p15 LOM allowing long-term follow-up studies and proposal of clinical guidelines. We also found that ∼10% of RSS patients and ∼25% of BWS patients have multilocus LOM at imprinted regions other than ICR1 or ICR2 11p15, respectively. Recent studies have identified cis-acting regulatory elements and trans-acting factors involved in the regulation of 11p15 imprinting, establishing new potential mechanisms of RSS and BWS.
authors.affiliation: Laboratoire d'Explorations Fonctionnelles Endocriniennes, APHP, Hôpital Armand Trousseau, INSERM UMRS-938 team 4, Université Pierre et Marie Curie-Paris 6, Paris, France. irene.netchine@trs.aphp.fr
authors.forename: Irène
authors.initials: I
authors.lastname: Netchine
authors.forename: Sylvie
authors.initials: S
authors.lastname: Rossignol
authors.forename: Salah
authors.initials: S
authors.lastname: Azzi
authors.forename: Fréderic
authors.initials: F
authors.lastname: Brioude
authors.forename: Yves
authors.initials: Y
authors.lastname: Le Bouc
mesh_terms: D017668:Age of Onset; D001506:Beckwith-Wiedemann Syndrome / Q000235:genetics*; D002648:Child; D005260:Female; D005315:Fetal Diseases / Q000235:genetics*; D018392:Genomic Imprinting / Q000502:physiology*; D006130:Growth Disorders / Q000151:congenital / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D008954:Models, Biological; D011247:Pregnancy; D056730:Silver-Russell Syndrome / Q000235:genetics*