Beckwith-Wiedemann syndrome is a genetic disorder caused by mutations on chromosome 11. It is characterized by macrosomia, occasionally hemihyperplasia, and a significant predisposition to several tumors, both benign and malignant. Fifty percent of Beckwith-Wiedemann cases are attributable to inappropriate methylation. It occurs in approximately 1:13 700 newborns.

Phenotype of Beckwith-Wiedemann syndrome is highly variable, as this is a spectrum disorder with variable presentation. Characteristic features include omphalocele, macroglossia, macrosomia (gigantism), gastroschisis, hemihypertrophy, hypoglycemia (usually mild and transient), creased ear lobes, and cleft palate. Other birth abnormalities are large birth weight, polyhydramnios, umbilical hernia, hemihyperplasia, cardiomegaly, septal defects, and premature birth. Developmental delay may occur. Embryonal tumors include hepatoblastoma, neuroblastoma, Wilms tumor, adrenal tumors, and rhabdomyosarcoma.

Pregnancy could be complicated with polyhydramnios, placental mesenchymal dysplasia, and prematurity.

Management focuses on treatment of hypoglycemia and other problematic symptoms, and includes corrective surgery, speech therapy, and treatment of tumor growth.

Inheritance is typically spontaneous, as the majority of Beckwith-Wiedemann diagnoses are isolated within a family. In the 10%-15% of families with several affected individuals, there is likely an autosomal dominant inheritance.