Table 2.
The etiological causes of SRS and BWS, prevalence among diagnosed cases and references
| Etiological causes | Prevalence among diagnosed SRS cases | Prevalence among diagnosed BWS cases |
|---|---|---|
| UPD7 | maternal 5–10% [Kotzot et al., 1995; Eggermann et al., 1997; Preece et al., 1997; Netchine et al., 2007; Abu-Amero et al., 2008; Binder et al., 2008] | – |
| Methylation abnormality at ICR1 in the 11p15 region | hypomethylation in 37- 63% [Netchine et al., 2007; Binder et al., 2008; Bartholdi et al., 2009; Bruce et al., 2009; Abu-Amero et al., 2010; Turner et al., 2010; Vals et al., 2015b] | hypermethylation 5–10% [Gaston et al., 2001; Cooper et al., 2005, 2007; Sasaki et al., 2007] |
| Methylation abnormality at ICR2 in the 11p15 region | few cases with the hypomethylation of both ICRs [Begemann et al., 2011] | hypomethylation in 50–60% [Gaston et al., 2001; Cooper et al., 2005; Weksberg et al., 2010; Begemann et al., 2012b] |
| Duplication in the 11p15 region (may involve ICR1 and/or ICR2) | maternal 1–2% [Eggermann et al., 2010a, 2014b] | paternal microdeletions involving ICR1 (~5%) and microduplications of ICR2 (<1%) [Niemitz et al., 2004; Sparago et al., 2004; Bliek et al., 2009b; Demars et al., 2011; Begemann et al., 2012b; Vals et al., 2015a] |
| Other chromosomal aberrations (including cryptic) | 2% (the most frequent are 1q21 microdeletion, 12q24 microdeletion, ring chromosome 15, and deletion 15qter) [Bruce et al., 2010; Spengler et al., 2012; Fuke et al., 2013; Fokstuen and Kotzot, 2014; Azzi et al., 2015] | rare cases, maternally inherited balanced translocations/inversions [Begemann et al., 2012b] |
| UPD11 | maternal single case [Bullman et al., 2008] | paternal 20–27% [Henry et al., 1991; Gaston et al., 2001; Cooper et al., 2005, 2007] |
| CDKN1C gene mutations | gain-of-function mutation, single case [Brioude et al., 2013] | loss-of-function mutations 8- 10%, familial 50–68%, and sporadic cases 5- 31% [Cooper et al., 2005; Weksberg et al., 2010; Eggermann et al., 2014a; Brioude et al., 2015] |
| HMGA2 gene mutations | single case [De Crescenzo et al., 2015] | – |
| Structural mutations in the H19/IGF2 enhancer region | rare cases [Grønskov et al., 2011] | – |
| Paternally inherited IGF2 nonsense mutation | 4 cases [Begemann et al., 2015] | – |
| Unknown etiology | 30–40% [Binder et al., 2008; Wakeling, 2011; Azzi et al., 2015] | 13–15% [Weksberg et al., 2010] |