title: Beckwith-Wiedemann syndrome caused by maternally inherited mutation of an OCT-binding motif in the IGF2/H19-imprinting control region, ICR1.
abstract: The imprinted expression of the IGF2 and H19 genes is controlled by the imprinting control region 1 (ICR1) located at chromosome 11p15.5. DNA methylation defects involving ICR1 result in two growth disorders with opposite phenotypes: an overgrowth disorder, the Beckwith-Wiedemann syndrome (maternal ICR1 hypermethylation in 10% of BWS cases) and a growth retardation disorder, the Silver-Russell syndrome (paternal ICR1 loss of methylation in 60% of SRS cases). In familial BWS, hypermethylation of ICR1 has been found in association with microdeletion of repetitive DNA motifs within ICR1 that bind the zinc finger protein CTCF; but more recently, ICR1 point mutations were described in BWS pedigrees. We present a case report of two brothers with BWS and prolonged post-pubertal growth resulting in very large stature. A maternally inherited point mutation was identified in ICR1 in both brothers, which altered binding of OCT transcription factors. The same mutation was present on the paternally inherited allele of their unaffected mother. This is a second report of a point mutation causing ICR1 hypermethylation by altering an OCT-binding motif. The atypical growth phenotype of the brothers may be connected to the unusual underlying cause of their BWS.
authors.affiliation: Faculty of Medicine, University of Southampton, Southampton, UK.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Poole
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Leith
authors.forename: Louise E
authors.initials: LE
authors.lastname: Docherty
authors.forename: Mansur E
authors.initials: ME
authors.lastname: Shmela
authors.forename: Christine
authors.initials: C
authors.lastname: Gicquel
authors.forename: Miranda
authors.initials: M
authors.lastname: Splitt
authors.forename: I Karen
authors.initials: IK
authors.lastname: Temple
authors.forename: Deborah J G
authors.initials: DJ
authors.lastname: Mackay
mesh_terms: D000483:Alleles; D001483:Base Sequence; D001506:Beckwith-Wiedemann Syndrome / Q000175:diagnosis / Q000235:genetics*; D001665:Binding Sites / Q000235:genetics; D002675:Child, Preschool; D019175:DNA Methylation; D023061:Gene Order; D018392:Genomic Imprinting; D005838:Genotype; D006801:Humans; D007223:Infant; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D008297:Male; D009154:Mutation; D050810:Octamer Transcription Factors / Q000378:metabolism*; D010375:Pedigree; D010641:Phenotype; D011401:Promoter Regions, Genetic; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics*
chemical_list: C094335:H19 long non-coding RNA; D050810:Octamer Transcription Factors; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D007335:Insulin-Like Growth Factor II