Having a family history of CNS tumours is associated with increased risk of developing a brain tumour, pooled analyses have shown.[1,2] Having a parent with a CNS tumour is associated with a 70% increased risk of being diagnosed with a brain or CNS tumour oneself, compared with the general population, and having a sibling diagnosed is associated with a doubling of risk.[1,2]
Those with any first-degree relative (parent, sibling or child) diagnosed with glioma have a 77% increased risk of developing glioma themselves, and a 2.2- to 2.6-fold risk increase if the affected relative is a sibling.[2,3]
Having a parent or sibling with meningioma confers a more than doubled (130% increased) risk of meningioma.
The magnitude of risk increases associated with family history varies by brain tumour subtype, but small sample sizes for these less common tumours preclude firm conclusions.
Neurofibromatoses (NF) are a group of genetic conditions in which benign (non-invasive) growths affect the nervous system. NF type 1 (NF1) is thought to affect around 1 in 2,700 live births in the UK, whilst NF type 2 (NF2) affects around 1 in 33,000.
The risk of brain and CNS tumours is at least 23-43 times higher in NF1 patients than in the general population.[5,6] The risk of CNS tumours excluding those in the brain may be considerably higher. Relative risk of brain tumours in NF1 patients increases with patient age. Most NF1-associated brain tumours are gliomas.
Both children and adults with NF1 have an increased risk of astrocytoma, with the tumour grade often higher in adults than children. 5-25% of children with NF1 develop optic pathway gliomas.
NF2 patients are commonly diagnosed with bilateral vestibular schwannomas (acoustic neuromas). These affect 90-95% of NF2 patients, and they are typically benign but can cause hearing impairment. Meningiomas affect 45-58% of NF2 patients, and usually arise at a younger age in these patients than in the general population.
Tuberous sclerosis complex (TSC)
Tuberous sclerosis complex (TSC) causes benign tumors to grow in the brain and elsewhere. The prevalence of TSC is estimated at around 1 in 25,000.[9,10] Up to 20% of TSC patients develop subependymal giant-cell astrocytomas.
Li-Fraumeni syndrome is a very rare genetic condition associated with increased risk of early-onset brain tumours and other cancer types. Astrocytomas, glioblastomas, medulloblastomas, and choroid plexus carcinomas are the most common brain tumours seen in this population.
Von Hippel-Lindau syndrome
Von Hippel-Lindau syndrome is thought to occur in around 1 in 43,000 live births in the UK. Haemangioblastomas of the brain or spinal cord occur in 60-80% of people with this condition.
Turner syndrome affects around 1 in 2,000 female live births. The risk of CNS tumours is around 4 times higher for Turner syndrome patients than the general population, with particularly increased risks of meningioma and childhood brain tumours.
Turcot’s syndrome is associated with both brain and bowel tumours. Turcot’s syndrome type 1 is associated with early-onset gliomas, whilst type 2 is associated with medulloblastoma.
Gorlin syndrome (nevoid basal cell carcinoma) is thought to occur in around 1 in 15,000 live births in the UK. Around 5-10% of people with this condition develop medulloblastomas.