Causes and risk factors of dementia

Frontotemporal dementias are not a single neurological disease, but rather a family of diseases that share certain features, such as selective neurodegeneration and atrophy of the brain's frontal and temporal lobes.

The loss of neurons in frontotemporal dementia is due to the pathological deposit of certain proteins in the brain. The most common are tau protein and TDP-43 protein. When these proteins present alterations, they accumulate in neurons and prevent them from functioning properly. In most cases, it is not known what causes these proteins to alter.  

In approximately 15-30% of cases, protein alterations are due to a genetic mutation. Mutations in the C9orf72, GRN or MAPT genes (among others) may be the genetic cause of frontotemporal dementia. In these cases, the disease may be passed down from parent to child. In other cases, the cause of the protein deposits that lead to neurodegeneration is unknown.