The spectrum of CDC73-related disorders includes the following phenotypes: Hyperparathyroidism-jaw tumor (HPT-JT) syndrome. Primary hyperparathyroidism, the main finding of HPT-JT syndrome, occurs in up to 95% of affected individuals; onset is typically in late adolescence or early adulthood. HPT-JT-associated primary hyperparathyroidism is usually caused by a single parathyroid adenoma. In approximately 10%-15% of individuals, primary hyperparathyroidism is caused by parathyroid carcinoma. Ossifying fibromas of the mandible or maxilla, also known as cementifying fibromas and cemento-ossifying fibromas, occur in 30%-40% of individuals with HPT-JT syndrome. Although benign, these tumors can be locally aggressive and may continue to enlarge if not treated. Approximately 20% of individuals with HPT-JT syndrome have kidney lesions, most commonly cysts; renal hamartomas and (more rarely) Wilms tumor have also been reported. Benign and malignant uterine tumors appear to be common in women with HPT-JT syndrome. Parathyroid carcinoma. Most parathyroid carcinomas are functional, resulting in hyperparathyroidism and a high serum calcium level; however, nonfunctioning parathyroid carcinomas are also rarely described in individuals with a CDC73-related disorder. A germline CDC73 pathogenic variant has been identified in 20%-29% of individuals with apparently sporadic parathyroid carcinoma. Familial isolated hyperparathyroidism (FIHP). FIHP is characterized by primary hyperparathyroidism without other associated syndromic features. Individuals with CDC73-related FIHP tend to have a more severe clinical presentation and younger age of onset than individuals with FIHP in whom a CDC73 pathogenic variant has not been identified.

Melanoma-pancreatic cancer syndrome is an inherited cancer predisposition syndrome in which mutation carriers have an increased risk of developing malignant melanoma and/or pancreatic cancer. Mutation carriers within families may develop either or both types of cancer (summary by Harinck et al., 2012). For background and phenotypic information on malignant melanoma and pancreatic cancer, see 155600 and 260350, respectively.

Any familial pancreatic carcinoma in which the cause of the disease is a mutation in the PALLD gene.

Individuals with mutation in the PALB2 gene have an increased risk of developing pancreatic cancer. In addition, PALB2 variants increase susceptibility to several other cancers, e.g., familial breast-ovarian cancer (BROVCA5; 620422) (Jones et al., 2009; Yang et al., 2020). For background, phenotypic description, and a discussion of genetic heterogeneity of pancreatic carcinoma, see 260350.

NTHL1 tumor syndrome is characterized by an increased lifetime risk for colorectal cancer (CRC), breast cancer, and colorectal polyposis. Colorectal polyps can be adenomatous, hyperplastic, and/or sessile serrated. Duodenal polyposis has also been reported. Additional cancers reported in individuals with NTHL1 tumor syndrome include endometrial cancer, cervical cancer, urothelial carcinoma of the bladder, meningiomas, unspecified brain tumors, basal cell carcinomas, head and neck squamous cell carcinomas, and hematologic malignancies. The cumulative lifetime risk of developing extracolonic cancer by age 60 years has been estimated at 35% to 78%.

Susceptibility to pancreatic ductal adenocarcinoma (PDAC) may be conferred by mutation in RABL3. Other cancers, including melanoma, breast cancer, and colon cancer, have been reported in RABL3 mutation-carrying individuals, with or without PDAC (Nissim et al., 2019). For background, phenotypic description, and a discussion of genetic heterogeneity of pancreatic carcinoma, see 260350.