The average age at diagnosis is 64, and the disease occurs more commonly in males than females. Signs and symptoms
Common symptoms include seizures, headaches, nausea and vomiting, memory loss, changes to personality, mood or concentration, and localized neurological problems. The kind of symptoms produced depends more on the location of the tumor than on its pathological properties. The tumor can start producing symptoms quickly, but occasionally is an asymptomatic condition until it reaches an enormous size. Risk factors
The cause of most cases is unclear. About 5% develop from another type of brain tumor known as a low-grade astrocytoma. Genetics
Uncommon risk factors include genetic disorders such as neurofibromatosis, Li–Fraumeni syndrome, tuberous sclerosis, or Turcot syndrome. Previous radiation therapy is also a risk. For unknown reasons, it occurs more commonly in males. Environmental
Other associations include exposure to smoking, pesticides, and working in petroleum refining or rubber manufacturing.Glioblastoma has been associated with the viruses SV40, HHV-6, and cytomegalovirus. Other
Research has been done to see if consumption of cured meat is a risk factor. No risk had been confirmed as of 2013. Similarly, exposure to radiation during medical imaging, formaldehyde, and residential electromagnetic fields, such as from cell phones and electrical wiring within homes, have been studied as risk factors. As of 2015, they had not been shown to cause GBM. Pathogenesis
The cellular origin of glioblastoma is unknown. Because of the similarities in immunostaining of glial cells and glioblastoma,  gliomas such as glioblastoma have long been assumed to originate from glial-type cells.
The cilia defects adversely affect "numerous critical developmental signaling pathways" essential to cellular development and thus offer a plausible hypothesis for the often multi-symptom nature of a large set of syndromes and diseases. Known ciliopathies include primary ciliary dyskinesia, Bardet–Biedl syndrome, polycystic kidney and liver disease, nephronophthisis, Alström syndrome, Meckel–Gruber syndrome and some forms of retinal degeneration. See also
Anencephaly

Notes
External links
NINDS Overview
Obgyn.net