Methylation Status of The KCNQ1OT and H19 Genes in Beckwith-Wiedemann Syndrome

Beckwith- Wiedemann syndrome (BWS) is an overgrowth disorder involving developmental abnormalities, tissue and organ hyperplasia and increased risk of embryonal tumours. It is caused by dysregulation of the expression of imprinted genes in the 11 p 15 chromosomal region. Molecular diagnosis of BWS· is currently difficult, mostly due to the large spectrum of genetic and epigenetic abnormalities. KCNQ10T (also known as LlT1 or KvDMR1) is an imprinted antisense transcript within KCNQ1 gene which was recently shown to be normally expressed from the paternal allele. A loss of imprinting of the KCNQ10T gene was described in 50-60 % of BWS patients (1 ). The aim of this study was to assess the methylation status of the KCNQ10T and H 19 genes in patients with BWS. The study included three patients (two males and one female) diagnosed clinically as BWS. All thethree patients showed hypomethylation of the KCNQ10T gene and did not show abnormal methylation of the H 19 gene. None of the three patients developed tumours in the follow up period.