Hereditary Transthyretin Amyloidosis
What is Hereditary Transthyretin Amyloidosis?
Hereditary Transthyretin Amyloidosis (hATTR) is an inherited, progressive, and debilitating disease that affects an individual's peripheral nerves, sensory organs, heart, and autonomic nervous systems. It is caused by a mutation in the transthyretin (TTR) gene, which produces an abnormal protein called transthyretin (TTR). This protein accumulates in tissues and organs in the body, leading to tissue and organ damage and eventually organ failure. In some cases, the disease is slowly progressive, but in others it can cause a rapid decline in health status, leading to organ failure and death.
Symptoms of Hereditary Transthyretin Amyloidosis
Common symptoms of hATTR include sensory and motor nerve damage, affecting the hands and feet; autonomic nerve damage, which affects the bladder, intestine, and eyes; and cardiac issues caused by a build-up of the abnormal transthyretin protein in the heart. The most common symptom is a gradual progressive sensory and motor neuropathy, which can cause numbness, tingling, pain, and muscle weakness in the limbs. Other symptoms may include:
- Difficulties with vision
- Abnormal sweating
- Sensitivity to temperature
- Abnormal heartbeat and/or high blood pressure
- Loss of appetite and/or weight loss
- Breathlessness
- Pain and/or cramps
Diagnosis of Hereditary Transthyretin Amyloidosis
In order to diagnose hATTR, a physician may perform a physical exam and neurological assessment, as well as order tests such as an electrocardiogram (ECG) and electromyography (EMG). These tests help to assess the integrity of the nerves and muscles in the body. In some cases, a biopsy may be performed to detect the abnormal transthyretin protein in the affected organs. Other tests may also be requested to check for organ dysfunction, such as a blood test or imaging tests such as an MRI or CT scan.
Treatment of Hereditary Transthyretin Amyloidosis
Treatment of hATTR depends on the stage and severity of the disease. In early stages, medications such as vitamin B supplements and antidepressants may be prescribed to improve nerve symptoms and improve quality of life. In the later stages, medications such as tafamidis, an oral medication designed to stabilize the abnormal protein, or patisiran, an RNA interference therapy, may be used to slow down the progression of the disease. In some cases, a liver transplant may also be considered.