Monozygotic twinning and Wiedemann‐Beckwith syndrome

Abstract

Monozygotic (MZ) twinning occurs with relatively high frequency in Wiedemann-Beckwith syndrome (WBS). Ten sets of MZ twins with WBS have been reported. Nine of these have been female and in each case the twins were discordant for the WBS phenotype. The tenth set was male. They were concordant for WBS and both had a duplication of chromosome 15 which they shared in common with their phenotypically normal mother. The WBS gene has been assigned to the locus 11p15 and there appear to be several different genetic mechanisms involving this locus which all give rise to WBS. An imprinting effect for the WBS gene has been proposed because of the transmission of the gene preferentially through the maternal line in some large pedigrees. We describe two further sets of female MZ twins with WBS. One pair is concordant and one discordant for the condition. The possible genetic mechanisms involved in the expression of WBS are discussed, with particular reference to twinning, genomic imprinting and X-inactivation which is thought to be associated with the occurrence of MZ twinning in females.

Paternal uniparental disomy in monozygotic twins discordant for hemihypertrophy

“…In addition, the association of BWS with monozygotic twins of discordant phenotype is well reported, with the majority of these twins being female. [8][9][10][11][12][13] BWS has a frequency of 1/13 700 live births and is sporadic in most cases. 14 The most consistent features of the syndrome are macrosomia, macroglossia, abdominal wall defects, hemihypertrophy, and increased risk of embryonal tumours including Wilms tumour.…”

Lessons from BWS twins: complex maternal and paternal hypomethylation and a common source of haematopoietic stem cells

“…The unaffected twin of an MZ pair described by Clayton-Smith 43 showed macroglossia, naevus flammeus and earlobe creases. 42,43 In another MZ twin pair, 21 the unaffected twin showed a small umbilical hernia, and transient neonatal macroglossia and naevus flammeus were observed by Olney 42 in a further unaffected MZ twin. In none of these three cases was the aetiology of disease established.…”

Beckwith–Wiedemann syndrome

“…There have been multiple reports of monozygotic twins with BWS [Berry et al, 1980;Bose et al, 1985;Litz et al, 1988;Olney et al, 1988;Chien et al, 1990;Clayton-Smith et al, 1992;Franceschini et al, 1993;Orstavik et al, 1995;Leonard et al, 1996]. We had the opportunity to investigate a cohort of monozygotic twins discordant for BWS.…”