Is Fatal Familial Insomnia hereditary?

Fatal Familial Insomnia (FFI) is a rare and devastating genetic disorder that affects the sleep-wake cycle. It is an autosomal dominant disorder, which means that it can be passed down from one generation to the next.

The PRNP gene mutation is responsible for causing FFI. This gene provides instructions for making a protein called prion protein (PrP), which is found throughout the body but is most abundant in the brain. The mutation leads to the production of an abnormal form of PrP, which accumulates in the brain and causes the characteristic symptoms of FFI.

Since FFI is an autosomal dominant disorder, an affected individual has a 50% chance of passing the mutated gene to each of their children. This means that if one parent has FFI, each child they have has a 50% chance of inheriting the disorder.

It is important to note that not everyone who inherits the mutated gene will develop FFI. The age of onset and severity of symptoms can vary among individuals. Some individuals may never develop symptoms, while others may experience them later in life.

Genetic testing can be performed to determine if an individual carries the PRNP gene mutation associated with FFI. However, since FFI is an extremely rare disorder, genetic testing is typically only recommended for individuals with a family history of the disease or those who are experiencing unexplained sleep disturbances.

In conclusion, Fatal Familial Insomnia is hereditary and can be passed down through generations due to a mutation in the PRNP gene. However, not everyone who inherits the mutated gene will develop the disorder, and the age of onset and severity of symptoms can vary.