Familial Amyloid Neuropathy (FAN), also known as Familial Amyloid Polyneuropathy (FAP), is a rare genetic disorder characterized by the accumulation of amyloid proteins in various nerves throughout the body. These proteins are abnormal and misfolded, leading to the formation of amyloid fibrils, which can accumulate and deposit in tissues, causing inflammation and damage.
FAN is typically an inherited condition, passed down through generations in an autosomal dominant pattern. It is caused by mutations in the transthyretin (TTR) gene, which produces a protein primarily synthesized in the liver. Defects in the TTR gene result in the production of unstable transthyretin, which forms amyloid deposits, primarily affecting peripheral nerves, but also potentially impacting other organs, such as the heart and kidneys.
Symptoms of Familial Amyloid Neuropathy may vary depending on the individual, but frequently include sensory disturbances, such as numbness, tingling, and pain in the limbs, muscle weakness, and autonomic dysfunction, which can manifest as abnormalities in blood pressure, heart rate, and gastrointestinal function.
Diagnosis of FAN often involves a combination of clinical evaluation, genetic testing, nerve biopsies, and imaging techniques to identify amyloid deposits. Treatment options for FAN are limited, and management primarily focuses on symptom relief and slowing disease progression. Liver transplantation may be considered in some cases, as it can provide a source of functional and non-mutated transthyretin protein.
In summary, Familial Amyloid Neuropathy is a hereditary disorder characterized by the accumulation of misfolded amyloid proteins, primarily in peripheral nerves, leading to a variety of neurological symptoms and potential organ damage.
