Familial glioma: occurrence within the "familial cancer syndrome" and systemic malformations

Genetic and epigenetic contribution to astrocytic gliomas pathogenesis

Astrocytic gliomas are the most common and lethal form of intracranial tumors. These tumors are characterized by a significant heterogeneity in terms of cytopathological, transcriptional, and (epi)genomic features. This heterogeneity has made these cancers one of the most challenging types of cancers to study and treat. To uncover these complexities and to have better understanding of the disease initiation and progression, identification, and characterization of underlying cellular and molecular pathways related to (epi)genetics of astrocytic gliomas is crucial. Here, we discuss and summarize molecular and (epi)genetic mechanisms that provide clues as to the pathogenesis of astrocytic gliomas.

Familial brain tumours-genetics or environment? A nationwide cohort study of cancer risk in spouses and first-degree relatives of brain tumour patients

Our study investigated whether the familial aggregation of glioma is due to environmental or genetic effects and it investigated and compared the risk to spouses and first-degree relatives (FDR) of patients with primary brain tumours (PBT) for developing both PBT and the risk for other types of cancer. All PBT patients identified in Sweden from 1958-97 in The Swedish Cancer Registry (SCR) were linked to the nationwide Swedish Family Database, including persons in Sweden born from 1932-97. The cohorts of spouses and FDR were linked to the SCR to identify observed cases of PBT and other cancer. Standardised incidence ratios (SIR) were calculated using the incidence rates from SCR as the reference. We found that there were no increased risks for any specific type of PBT in the cohort of spouses. In the FDR cohort, generally the risk for a PBT was significantly increased by 2 to 3 times for the same histopathology as the probands. Spouses of PBT patients had an increased risk of skin cancer. We conclude that FDR, not spouses, have a significantly increased risk, which indicates a genetic origin of the familial aggregation of brain tumours.

Genetic epidemiology of glioma

The present study performed a segregation analysis of a cohort of first-degree relatives (FDR) of glioma patients. The families with two or more gliomas were also expanded to determine if any more gliomas could be detected, and if any other types of cancers were associated. These glioma-prone families (n = 24/432) were extended to include first-, second- and third-degree relatives (n = 807) and a cohort was assembled, the standardized incidence risk for other types of cancer calculated and the pedigrees investigated for a possible mode of inheritance. A segregation analysis of the 2141 FDR in 297 families, performed using the Pointer software, did not clearly reject a multifactorial model chi(2)(3) = 6.13, P< 0.2. However, when letting all parameters be free, the recessive model provided the best fit. In the extended families, no increased risk of other types of cancer was found. This population-based study proposes that familial glioma occurs in about 5% of all glioma cases and that 1% have a possible autosomal dominant inheritance. This first segregation analysis performed in familial glioma must be cautiously interpreted, but an autosomal recessive gene provided the best fit, which could possibly explain 2% of all glioma cases.

Familial brainstem glioma

Two young males with a high degree of consanguinity presented with similar brainstem gliomas. As the patients were raised separately, their presentation with similar tumors suggests a genetic basis for the occurrence of these gliomas.

Glioblastoma multiforme in four siblings: a cytogenetic and molecular genetic study

The familial occurrence of gliomas, in the absence of well-defined neurological tumor syndromes such as the neurofibromatoses, is uncommon. We present a family of ten children in which the four eldest suffered from gliomas. Three of these siblings had histologically verified glioblastoma multiforme, and one patient also had an intestinal non-Hodgkin's lymphoma, but there were no stigmata or family history of a neurological tumor syndrome. Cytogenetic studies of the proband revealed a normal karyotype. Molecular genetic analysis of the proband's glioblastoma revealed two mutations in the p53 tumor suppressor gene, but these were not present in the germline DNA, mutations were not detected in the MTS1 gene in the tumors or in the germline DNA. These findings suggest that a genetic factor may be responsible for the clustering of glial tumors in this family, but it is unlikely that the genetic alteration is mutation of the p53 gene. The data are discussed in light of the literature on familial brain tumors.

Genetics of primary brain tumors: a review

In this review we provide evidence for the existence of genes associated with primary malignant brain tumors. We summarize the current knowledge from studies of familial cancer aggregation, hereditary syndromes, and molecular and cytogenetic studies. The epidemiologic evidence is suggestive but inconclusive for an association between brain tumors and cancers in other family members, including cancers of the breast, lung and colon. Central nervous system (CNS) tumors have been associated with several hereditary syndromes including the Li-Fraumeni cancer family syndrome, neurofibromatosis (types 1 and 2), tuberous sclerosis, nevoid basal cell carcinoma syndrome, familial polyposis, and von Hippel-Lindau disease. Significant studies leading to the recognition of molecular and cytogenetic abnormalities in malignant gliomas are described in detail. The genetic studies conducted thus far suggest a role for inherited susceptibility in some CNS tumors.

Familial clustering of malignant astrocytomas

Three of 32 consecutive patients with astrocytomas enrolled in an experimental chemotherapy protocol had at least one first degree relative with an astrocytoma. These patients did not have family members with an excess of malignancies, known exposure to a specific environmental factor, or a recognized neurocutaneous syndrome. In all three families, the illnesses temporally overlapped and the age of the patients affected in the second generation was less than those in the first generation. An estimation of the probability of developing astrocytomas in families with one affected individual strongly suggests a familial effect. Our observations, coupled with other cases reported in the literature, suggest that familial astrocytomas occur more frequently than is currently recognized. Identification and careful study of such families may provide important clues to the etiology of these malignancies.

Clinico-neurological investigations in the fra(X) form of mental retardation

A clinical, neurological and electroencephalographic investigation was undertaken in 29 previously cytogenetically verified hemizygous males with the fra(X) form of mental retardation (age range 3.5 to 59 years); in addition, 6 heterozygous females were examined. All male patients displayed the known physical aspects of this syndrome together with associated abnormalities of the palate, skeleton, connective tissue and endocrine system. The most prominent neurological features were different forms of oculomotor disturbances, minor motor and pyramidal signs, incoordination, muscle hypotonia, gait and speech abnormalities. There was no increased frequency either in seizures or in epileptic EEG discharges. Some patients had a slowing of background activity in EEG. About 50% of all patients displayed autistic-like behaviour, short attention span and/or hyperactivity. In accordance with the literature, the findings indicate that there are no neurological, electroencephalographic or neuroradiological features which occur specifically in this syndrome. The need to differentiate the findings from those resulting from encephalopathic mechanisms during the gestational and perinatal period is stressed. A distinct typing of seizures and EEG changes is needed in each patient, before definite conclusions about an association of seizures and fra(X) syndrome are drawn. In view of the lack of correlation between IQ and the clinical-neurological measures, a more practical approach to quantifying the mental impairment is proposed.