MedGen

Any malignant glioma in which the cause of the disease is a mutation in the BRCA2 gene. [from MONDO]

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. [from GeneReviews]

Medulloblastoma is the most common brain tumor in children. It accounts for 16% of all pediatric brain tumors, and 40% of all cerebellar tumors in childhood are medulloblastoma. Medulloblastoma occurs bimodally, with peak incidences between 3 and 4 years and 8 and 9 years of age. Approximately 10 to 15% of medulloblastomas are diagnosed in infancy. Medulloblastoma accounts for less than 1% of central nervous system (CNS) tumors in adults, with highest incidence in adults 20 to 34 years of age. In 1 to 2% of patients, medulloblastoma is associated with Gorlin syndrome (109400), a nevoid basal carcinoma syndrome. Medulloblastoma also occurs in up to 40% of patients with Turcot syndrome (see 276300). Medulloblastoma is thought to arise from neural stem cell precursors in the granular cell layer of the cerebellum. Standard treatment includes surgery, chemotherapy, and, depending on the age of the patient, radiation therapy (Crawford et al., 2007). Millard and De Braganca (2016) reviewed the histopathologic variants and molecular subgroups of medulloblastoma. Pretreatment prognosis of medulloblastoma has been refined by histopathologic subclassification into the following variants: large-cell medulloblastoma, anaplastic medulloblastoma, desmoplastic/nodular medulloblastoma, and medulloblastoma with extensive nodularity (MBEN). The latter 2 groups have been shown to have a significantly superior prognosis as compared to the large cell and anaplastic groups in young children. At the molecular level, medulloblastomas have been categorized into the following subgroups: wingless (WNT), sonic hedgehog (SHH), group 3, and group 4. Each subgroup is characterized by a unique set of genetics and gene expression as well as demographic and clinical features. [from OMIM]

Lynch syndrome is characterized by an increased risk for colorectal cancer (CRC) and cancers of the endometrium, ovary, stomach, small bowel, urinary tract, biliary tract, brain (usually glioblastoma), skin (sebaceous adenomas, sebaceous carcinomas, and keratoacanthomas), pancreas, and prostate. Cancer risks and age of onset vary depending on the associated gene. Several other cancer types have been reported to occur in individuals with Lynch syndrome (e.g., breast, sarcomas, adrenocortical carcinoma). However, the data are not sufficient to demonstrate that the risk of developing these cancers is increased in individuals with Lynch syndrome. [from GeneReviews]

The rhabdoid tumor predisposition syndrome is an autosomal dominant cancer syndrome predisposing to renal or extrarenal malignant rhabdoid tumors and to a variety of tumors of the central nervous system, including choroid plexus carcinoma, medulloblastoma, and central primitive neuroectodermal tumors (Sevenet et al., 1999). Rhabdoid tumors are a highly malignant group of neoplasms that usually occur in children less than 2 years of age. Malignant rhabdoid tumors (MRTs) of the kidney were first described as a sarcomatous variant of Wilms tumors (Beckwith and Palmer, 1978). Later, extrarenal rhabdoid tumor was reported in numerous locations, including the central nervous system (CNS) (Parham et al., 1994). Classification has been difficult because of considerable variation in the histologic and immunologic characteristics within and between rhabdoid tumors of the liver, soft tissues, and CNS. In the CNS, rhabdoid tumors may be pure rhabdoid tumors or a variant that has been designated atypical teratoid tumor (AT/RT). Genetic Heterogeneity of Rhabdoid Tumor Predisposition Syndrome See also RTPS2 (613325), caused by germline mutation in the SMARCA4 gene (603254) on chromosome 19p13. [from OMIM]

Nijmegen breakage syndrome (NBS) is characterized by progressive microcephaly, early growth deficiency that improves with age, recurrent respiratory infections, an increased risk for malignancy (primarily lymphoma), and premature ovarian failure in females. Developmental milestones are attained at the usual time during the first year; however, borderline delays in development and hyperactivity may be observed in early childhood. Intellectual abilities tend to decline over time. Recurrent pneumonia and bronchitis may result in respiratory failure and early death. Other reported malignancies include solid tumors (e.g., medulloblastoma, glioma, rhabdomyosarcoma). [from GeneReviews]

Fanconi anemia (FA) is characterized by physical abnormalities, bone marrow failure, and increased risk for malignancy. Physical abnormalities, present in approximately 75% of affected individuals, include one or more of the following: short stature, abnormal skin pigmentation, skeletal malformations of the upper and/or lower limbs, microcephaly, and ophthalmic and genitourinary tract anomalies. Progressive bone marrow failure with pancytopenia typically presents in the first decade, often initially with thrombocytopenia or leukopenia. The incidence of acute myeloid leukemia is 13% by age 50 years. Solid tumors – particularly of the head and neck, skin, and genitourinary tract – are more common in individuals with FA. [from GeneReviews]

Nevoid basal cell carcinoma syndrome (NBCCS) is characterized by the development of multiple jaw keratocysts, frequently beginning in the second decade of life, and/or basal cell carcinomas (BCCs) usually from the third decade onward. Approximately 60% of individuals have a recognizable appearance with macrocephaly, frontal bossing, coarse facial features, and facial milia. Most individuals have skeletal anomalies (e.g., bifid ribs, wedge-shaped vertebrae). Ectopic calcification, particularly in the falx, is present in more than 90% of affected individuals by age 20 years. Cardiac and ovarian fibromas occur in approximately 2% and 20% of individuals respectively. Approximately 5% of all children with NBCCS develop medulloblastoma (primitive neuroectodermal tumor), generally the desmoplastic subtype. The risk of developing medulloblastoma is substantially higher in individuals with an SUFU pathogenic variant (33%) than in those with a PTCH1 pathogenic variant (<2%). Peak incidence is at age one to two years. Life expectancy in NBCCS is not significantly different from average. [from GeneReviews]

DICER1 tumor predisposition (DICER1) is characterized by an increased risk for pleuropulmonary blastoma (PPB), pulmonary cysts, thyroid gland neoplasia (multinodular goiter, adenomas, and/or thyroid cancer), ovarian tumors (Sertoli-Leydig cell tumor, gynandroblastoma, and sarcoma), and cystic nephroma. Less commonly observed tumors include ciliary body medulloepithelioma, nasal chondromesenchymal hamartoma, embryonal rhabdomyosarcoma, pituitary blastoma, pineoblastoma, central nervous system (CNS) sarcoma, other CNS tumors, and presacral malignant teratoid tumor. The majority of tumors occur in individuals younger than age 40 years. PPB typically presents in infants and children younger than age six years. Ovarian sex cord-stromal tumors are most often diagnosed before age 40 years. Cystic nephroma generally presents in young children but has also been reported in adolescents. Additional clinical features that may be seen include macrocephaly, ocular abnormalities, structural anomalies of the kidney and collecting system, and dental anomalies (bulbous crowns). [from GeneReviews]

The basal cell nevus syndrome (BCNS), also known as Gorlin syndrome, is characterized by numerous basal cell cancers and epidermal cysts of the skin, calcified dural folds, keratocysts of the jaws, palmar and plantar pits, ovarian fibromas, medulloblastomas, lymphomesenteric cysts, fetal rhabdomyomas, and various stigmata of maldevelopment (e.g., rib and vertebral abnormalities, cleft lip or cleft palate, and cortical defects of bones) (summary by Koch et al., 2002). For a discussion of genetic heterogeneity of BCNS, see BCNS1 (109400). [from OMIM]