Beckwith-Wiedemann syndrome: An overgrowth syndrome, whose clinical manifestations typically include macrosomia (large body size), macroglossia (large tongue), omphalocele (exomphalos), organomegaly (enlarged organs), hemihypertrophy (overgrowth of one side of the body), neonatal hypoglycemia (low blood sugar in the newborn period), and ear creases and ear pits.
The majority (about 85%) of patients with Beckwith-Wiedemann syndrome (BWS) have no family history of it while a minority (about 15%) of patients have a family history with autosomal dominant transmission of the syndrome.
The genetics of BWS appear complex, in part no doubt because the underlying causes of the syndrome are still not entirely clear. In 50% of patients, there is loss of methylation at the KCNQ1OT1 gene in chromosome 11p15 while in 10-20% of patients, there is paternal uniparental disomy of chromosome 11p15. There are mutations in the CDKN1C gene in chromosome 11p15 in 5-10% of cases with no known family history of the syndrome and 40% of familial cases of the syndrome.
The syndrome is named for the American pediatric pathologist J. Bruce Beckwith (1933-) and the German pediatrician Hans-Rudolf Wiedemann (1915-). In 1964, Wiedemann reported a familial form of omphalocele with macroglossia in Germany and then in 1969, Beckwith described a similar series of patients in the US. Wiedemann coined the term EMG syndrome to describe the combination of exomphalos, macroglossia, and gigantism. In time, the condition was renamed Beckwith-Wiedemann syndrome. It is also sometimes called the Wiedemann-Beckwith syndrome (WBS) because Wiedemann recognized the syndrome before Beckwith.