Familial Amyloidosis, Finnish Type

Familial Amyloidosis, Finnish Type (FAF), also known as Finnish Type Amyloidosis or Meretoja’s Syndrome, is a rare genetic disorder characterized by the accumulation of amyloid protein in various tissues of the body. This condition is part of a group of diseases known as amyloidosis, where misfolded proteins aggregate and deposit in organs, leading to dysfunction. FAF specifically is caused by mutations in the gelsolin gene, leading to an abnormal variant of the gelsolin protein. This disease was first described in Finland, hence its name, and is more prevalent in individuals of Finnish descent, although cases have been reported worldwide.

Symptoms and Signs

The symptoms of Familial Amyloidosis, Finnish Type, typically begin to manifest in adulthood, usually around the age of 30 to 40. The disease is characterized by a triad of main symptoms: corneal lattice dystrophy, cutis laxa (loose skin), and polyneuropathy (nerve damage). Other symptoms may include:

• Facial paralysis
• Dry eyes and mouth
• Sensory loss in the extremities
• Autonomic nervous system dysfunction, leading to issues such as orthostatic hypotension
• Cardiac abnormalities

Genetics

FAF is inherited in an autosomal dominant manner, meaning that only one copy of the mutated gene is necessary for an individual to be at risk of developing the disease. The mutation responsible for FAF occurs in the gelsolin gene, which is located on chromosome 9. This gene normally codes for a protein involved in actin filament assembly and disassembly, crucial for cell movement and stability. The mutation leads to the production of an abnormal gelsolin protein, which then misfolds and aggregates as amyloid fibrils in tissues.

Diagnosis

Diagnosis of Familial Amyloidosis, Finnish Type involves a combination of clinical evaluation, family history, and genetic testing. Ophthalmological examination can reveal corneal lattice dystrophy, a key indicator of the disease. Nerve conduction studies and biopsy of affected tissues may also be utilized to detect amyloid deposits. Genetic testing is definitive, identifying the specific mutation in the gelsolin gene.

Treatment

There is no cure for FAF, and treatment focuses on managing symptoms and preventing complications. This may include:

• Lubricating eye drops for dry eyes
• Physical therapy and pain management for neuropathy
• Surgical interventions for severe corneal dystrophy
• Monitoring and treating cardiac and autonomic nervous system involvement

Prognosis

The prognosis for individuals with Familial Amyloidosis, Finnish Type varies. While the disease tends to progress slowly, it can significantly impact quality of life due to vision loss and neuropathy. Early diagnosis and management of symptoms are crucial in improving outcomes.

Epidemiology

FAF is most common in individuals of Finnish descent, but it has been identified in various populations worldwide. The exact prevalence is unknown due to the rarity of the condition.

See Also

• Amyloidosis
• Genetic Disorders
• Neuropathy
• Corneal Dystrophy