Beckwith-Wiedemann syndrome (BWS) is a growth disorder variably characterized by macroglossia, hemihyperplasia, omphalocele, neonatal hypoglycemia, macrosomia, embryonal tumors (e.g., Wilms tumor, hepatoblastoma, neuroblastoma, and rhabdomyosarcoma), visceromegaly, adrenocortical cytomegaly, kidney abnormalities (e.g., medullary dysplasia, nephrocalcinosis, and medullary sponge kidney), and ear creases / posterior helical ear pits. BWS is considered a clinical spectrum, in which affected individuals may have many or only one or two of the characteristic clinical features. Although most individuals with BWS show rapid growth in late fetal development and early childhood, growth rate usually slows by age seven to eight years. Adult heights are typically within the normal range. Hemihyperplasia (also known as lateralized overgrowth) is often appreciated at birth and may become more or less evident over time. Hemihyperplasia may affect segmental regions of the body or selected organs and tissues. Hemihyperplasia may be limited to one side of the body (ipsilateral) or involve opposite sides of the body (contralateral). Macroglossia is generally present at birth and can obstruct breathing or interfere with feeding in infants. Neonatal hypoglycemia occurs in approximately 50% of infants with BWS; most episodes are mild and transient. However, in some cases, persistent hypoglycemia due to hyperinsulinism may require consultation with an endocrinologist for therapeutic intervention. With respect to the increased risk for embryonal tumor development, the risk for Wilms tumor appears to be concentrated in the first seven years of life, whereas the risk for developing hepatoblastoma is concentrated in the first three to four years of life. Cognitive and neurobehavioral development is usually normal. After childhood, prognosis is generally favorable, although some adults experience issues requiring medical management (e.g., for renal or skeletal concerns).

Li-Fraumeni syndrome (LFS) is a cancer predisposition syndrome associated with high risks for a broad spectrum of cancers including early-onset cancers. Five cancer types account for the majority of LFS tumors: adrenocortical carcinomas, breast cancer, central nervous system tumors, osteosarcomas, and soft-tissue sarcomas. Other cancers associated with LFS include leukemia, colorectal cancer, stomach cancer, lung cancer, melanoma, pediatric head and neck cancers, pancreatic cancer, and prostate cancer. Cancer survivors are at increased risk for developing additional primary cancers and treatment-related secondary cancers. The lifetime risks of cancer for women and men with classic LFS are 90% and 70%, respectively, and 50% of cancers occur prior to age 40 years.

Adrenocortical carcinoma (ADCC) is a rare but aggressive childhood tumor, representing about 0.4% of childhood tumors, with a high incidence of associated tumors. ADCC occurs with increased frequency in patients with the Beckwith-Wiedemann syndrome (130650) and is a component tumor in Li-Fraumeni syndrome (LFS; 151623).

APC-associated polyposis conditions include (classic or attenuated) familial adenomatous polyposis (FAP) and gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). FAP is a colorectal cancer (CRC) predisposition syndrome that can manifest in either classic or attenuated form. Classic FAP is characterized by hundreds to thousands of adenomatous colonic polyps, beginning on average at age 16 years (range 7-36 years). For those with the classic form of FAP, 95% of individuals have polyps by age 35 years; CRC is inevitable without colectomy. The mean age of CRC diagnosis in untreated individuals is 39 years (range 34-43 years). The attenuated form is characterized by multiple colonic polyps (average of 30), more proximally located polyps, and a diagnosis of CRC at a later age than in classic FAP. For those with an attenuated form, there is a 70% lifetime risk of CRC and the mean age of diagnosis is 50-55 years. Extracolonic manifestations are variably present and include polyps of the stomach and duodenum, osteomas, dental abnormalities, congenital hypertrophy of the retinal pigment epithelium (CHRPE), benign cutaneous lesions, desmoid tumors, adrenal masses, and other associated cancers. GAPPS is characterized by proximal gastric polyposis, increased risk of gastric adenocarcinoma, and no duodenal or colonic involvement in most individuals reported.