Clinical and molecular characterization of Beckwith-Wiedemann syndrome in a Chinese population

Background: The objective of this study was to examine the clinical and molecular features, genotype-phenotype correlation and the efficacy of different diagnostic criteria for predicting a positive molecular test in Chinese -Beckwith-Wiedemann syndrome (BWS) patients. Methods: A retrospective tertiary-wide study was performed in Hong Kong with 27 molecularly confirmed BWS patients between January 2010 and September 2015. Results: It was observed that 48.1% of the BWS cases were caused by loss of methylation at differentially methylated region 2 (DMR2-LoM) of the 11p15.5 region, 11.1% by gain of methylation at differentially methylated region 1 (DMR1-GoM) of the 11p15.5 region, 33.3% by paternal uniparental disomy 11 [upd (11) pat] and 7.5% by CDKN1C mutation. Two out of 27 (7.4%) had embryonal tumors. Both belonged to the DMR1-GoM subtype with one Wilm's tumor diagnosed at 3 months of age and the other, hepatoblastoma, diagnosed at 6 months of age. However, no genotype-phenotype correlation can be concluded by this cohort study. Finally, for different clinical diagnostic criteria, the Debaun and Tucker criteria and the Ibrahim et al. weighing score system have the best performance for predicting a positive molecular test in our Chinese BWS cohort. Conclusions: It is the largest study of molecularly confirmed BWS in the Chinese. Their clinical and epigenetic features are comparable with other ethnic populations.