Type II Familial Amyloid Polyneuropathy (FAP) is a rare, hereditary disorder characterized by the abnormal buildup of amyloid proteins in various tissues throughout the body, leading to peripheral neuropathy.
Amyloid proteins are produced normally by the liver and play essential roles in various bodily functions, including cell signaling and metabolism. However, in individuals with Type II FAP, a specific genetic mutation causes the liver to produce abnormal forms of a protein called transthyretin (TTR), leading to its misfolding and aggregation into amyloid fibrils. These fibrils gradually accumulate in the peripheral nerves, heart, gastrointestinal tract, and other organs, interfering with their proper functioning.
The hallmark symptom of Type II FAP is peripheral neuropathy, which refers to damage or dysfunction of the peripheral nerves that control sensation and movement in the limbs. This often presents as numbness, tingling, and weakness, initially affecting the lower limbs and gradually progressing towards the upper body. Other symptoms may include autonomic dysfunction, such as dizziness and urinary incontinence, as well as cardiac abnormalities, gastrointestinal disturbances, and visual impairments.
Diagnosis of Type II FAP involves a combination of clinical evaluation, family history assessment, genetic testing to identify the specific mutation causing the disorder, and biopsy of affected tissues for confirmation of amyloid deposition. Unfortunately, there is currently no cure for Type II FAP, but treatment primarily focuses on managing symptoms, slowing the progression of the disease, and improving patients' quality of life. This may involve the use of medications to stabilize or reduce TTR levels, symptomatic relief through pain management and physical therapy, and potentially liver transplantation in advanced cases. Ongoing research is actively exploring the development of novel therapies to target the underlying mechanisms of the
