Absence of detectable chromosomal and molecular abnormalities in monozygotic twins discordant for the Wiedemann-Beckwith syndrome.

Monozygotic twins discordant for the Wiedemann-Beckwith syndrome (WBS) were studied by cytogenetic and molecular methods to determine if a genetic lesion could be detected in the affected child. Probes known to be localized on the short arm of chromosome 11 and a low copy-repetitive probe were used. No genetic lesions could be ascertained in normal or affected tissue obtained from the WBS twin.