What is hATTR amyloidosis?

Hereditary ATTR (hATTR) amyloidosis (ama-loy-doh-sis) is a rare, inherited condition that can progress rapidly and affects an estimated 50,000 people worldwide

It runs in the family

hATTR amyloidosis is caused by a variant (or change) in the transthyretin (TTR) gene. This change in the TTR gene may also be referred to as a mutation. If one parent has hATTR amyloidosis, each child will have a 50% chance of inheriting the genetic variant that causes the condition. However, inheriting a TTR gene variant doesn’t necessarily mean that they will develop hATTR amyloidosis.

Do you know how to discuss hATTR amyloidosis with your family?

Sharing accurate information with your family is key. It can help to involve your doctor or get in touch with an Alnylam Patient Education Liaison (PEL) to help with these conversations.

Symptoms of hATTR amyloidosis

hATTR amyloidosis can cause a range of symptoms that do not seem connected. Because of this, and because each person may experience different symptoms, people with hATTR amyloidosis are often misdiagnosed with other, more common conditions.

Some symptoms of hATTR amyloidosis are caused by polyneuropathy, which is damage to nerves that affects sensation, movement, strength, and bodily functions such as digestion, urination, and sexual function.

Click to reveal the polyneuropathy symptoms below

Symptoms related to the nerves in hands and feet, arms and legs:

  • Tingling and/or numbness
  • Burning pain
  • Loss of sensitivity to temperature
  • Carpal tunnel syndrome
  • Decreased reflexes
  • Weakness
  • Difficulty walking

Symptoms related to the digestive system:

  • Diarrhea
  • Severe constipation
  • Nausea and vomiting
  • Unintentional weight loss

Symptoms related to the heart:

  • Shortness of breath
  • Fatigue
  • Leg swelling (edema)
  • Palpitations and abnormal heart rhythms (atrial fibrillation)

Other symptoms:

  • Dizziness upon standing
  • Abnormal sweating
  • Urinary tract infections
  • Sexual dysfunction

This is not a complete list of symptoms that may be experienced with hATTR amyloidosis.
ONPATTRO® (patisiran) does not treat all of these symptoms.

As the disease progresses, quality of life can continue to decline

  • Decreased mobility
  • Trouble with self-care
  • Difficulty performing usual activities
  • Anxiety
  • Depression

Worsening symptoms may require a loved one to help you from time to time. Becoming a caregiver comes with a lot of responsibility, but there are tips and information in this downloadable Guide for Caregivers that may be helpful during the transition into this role.

How hATTR amyloidosis is diagnosed

hATTR amyloidosis is commonly misdiagnosed, as the symptoms may be similar to those of other conditions. Consider compiling your family’s medical history and tracking your symptoms to help your doctor determine the right course of action. If your doctor suspects you may be at risk for, or are currently exhibiting, symptoms related to hATTR amyloidosis, they may order a number of tests to confirm a diagnosis.

Some of the most common tests:

  • Neurological and/or cardiac evaluations, such as nerve conduction study (NCS), electrocardiography (ECG/EKG), and echocardiography (echo)
  • Tissue biopsy
  • Genetic testing