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Adrenomyeloneuropathy (AMN)

Adrenomyeloneuropathy (AMN) is the most common form of adrenoleukodystrophy (ALD). It affects adult men, typically presenting with a gradual onset of stiffness and weakness in the legs, difficulty with walking, and pain or discomfort due to nerve damage. Other symptoms can include bladder and bowel dysfunction, and sexual dysfunction. Unlike cerebral ALD, AMN progresses more slowly and does not usually involve severe cognitive decline, but it can lead to significant disability over time. While there is currently no cure for AMN, management focuses on symptom relief, physical therapy, and regular monitoring to address complications. Men with AMN might be eligible for a clinical trial with an investigational drug that might improve symptoms or slow progression of disease. Early recognition and supportive care are essential to improving quality of life for individuals living with AMN.

Diagnosis

Adrenomyeloneuropathy (AMN) is diagnosed through a combination of clinical evaluation, family history, and specialized testing. A definitive diagnosis is made through genetic testing, which identifies mutations in the ABCD1 gene. Biochemical tests measuring very long-chain fatty acids (VLCFAs) in the blood can also support the diagnosis, as elevated levels are indicative of the condition. Additional tests, such as nerve conduction studies or MRI, may be used to assess neurological involvement. Accurate diagnosis of AMN is essential for appropriate management and care.

Adrenomyeloneuropathy (AMN)

Symptoms

The symptoms of adrenomyeloneuropathy (AMN) can vary widely among individuals. Common symptoms include stiffness, weakness, and pain in the legs, which typically start gradually and may worsen over time. The nerves controlling the bladder, bowel, and sexual function can also be affected, leading to a range of complications. Mobility may gradually deteriorate, and while some individuals may eventually require a wheelchair, others may never reach that point. It’s important to note that the symptoms and progression of AMN can differ significantly from person to person. Below are some potential symptoms, though each individual’s experience with AMN is unique:

Adrenal insufficiency: Inadequate hormone production by the adrenal glands, affecting approximately 70% of men with AMN.
Ataxia: Loss of muscle coordination, impacting movement and balance.
Falling or tripping: Resulting from balance and coordination difficulties.
Fatigue and sleep disturbances: Persistent tiredness and challenges with sleep.
Hypertonia: Excessive muscle tone, leading to stiffness and rigidity.
Peripheral neuropathy: Pain, numbness, or tingling sensations in the legs or feet.
Sexual dysfunction: Issues with obtaining or maintaining an erection.
Spastic paraparesis: Progressive weakness and stiffness in the legs.
Thinning hair or balding: Less commonly associated directly with AMN but can occur in some cases, often related to the hormonal imbalances caused by adrenal insufficiency rather than the neurological aspects of AMN itself.
Urinary and bowel dysfunction: Urinary urgency, incontinence, or bowel urgency and incontinence.
Walking and balance problems: General leg weakness, stiffness, and decreased balance, which can progress to difficulty walking or an unusual gait. Mobility aids such as canes, walkers, or wheelchairs may be needed over time.

Newborn Screening/Monitoring

Standard of Care

International consensus guidelines recommend that all boys and men with ALD be monitored by MRI for the development of cerebral ALD and by bloodwork for the development of adrenal insufficiency even in the absence of symptoms. Managing adrenomyeloneuropathy (AMN) requires a comprehensive and proactive approach to care. Men with AMN should establish care with a multidisciplinary team, including a neurologist and endocrinologist, to address the wide range of symptoms associated with the disease. Neurological care is essential, as annual MRIs are recommended to monitor for the development of cerebral ALD. Endocrinological care is equally important; all men with AMN should be screened annually for adrenal insufficiency, even if they have not yet been diagnosed with it. For those already diagnosed with adrenal insufficiency, daily steroid replacement therapy is crucial, as it helps prevent potentially fatal complications.

Symptom management is another key aspect of care. This may include medications to alleviate spasticity, manage bladder and bowel dysfunction, and address other neurological symptoms. Physical and occupational therapy can help maintain mobility and improve quality of life. It’s important for men with AMN to work closely with their healthcare providers to tailor a care plan that meets their individual needs. Education about the signs of adrenal insufficiency and the importance of stress dosing during illness or injury is also vital to ensure quick and effective responses to any health changes.

CLINICAL TRIALS

Men with AMN might be eligible for a clinical trial with an investigational drug that might improve symptoms or slow progression of disease. Visit our Clinical Trials page to learn more.

Download MRI Information Sheet

Resources

ALD Connect hosts a Community Call for AMN Men each month. This call is usually on the fourth Tuesday of each month at 7 PM Eastern. Be sure to follow us on social media and subscribe to our newsletter to watch for the announcements. You can also bookmark our Community Calendar, which is where we post the links to register for the Community Calls. ALD Connect also hosts a peer mentor program, which connects less experienced community members to more experienced members of a similar phenotype. You can apply for a peer mentor here.

On May 7, 2021, ALD Connect hosted a Listening Session with the FDA regarding Men with AMN. Read the summary here. On July 22, 2022, ALD Connect hosted an Externally-Led Patient-Focused Drug Development Meeting to educate the FDA on adult manifestations of ALD, including AMN and adult cerebral ALD. View the recording and our resulting Voice of the Patient Report here.

On June 12, 2021, ALD Connect hosted a Bootcamp for Men with AMN. The recordings are below.

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