Adrenomyeloneuropathy (AMN)is a rare X-linked genetic disorder and a form of adrenoleukodystrophy (ALD). Though it affects men more severely, AMN also affects women. Symptoms begin between ages 20-40. AMN is caused by a buildup of very long chain fatty acids (VLCFAs). This buildup damages myelin, the fatty covering of the nerve and brain cells. When myelin breaks down, the nervous system has a hard time sending messages. Symptoms of AMN include urinary and genital tract infections and progressive stiffness and weakness in the legs. The VLCFAs will severely damage the brain and nervous system of 10-20% of men with AMN, leading to early death. Most people with AMN also have adrenocortical insufficiency or Addison’s disease, because the extra VLCFAs can damage the adrenal glands. These glands make hormones which help balance sugar and salt levels, and our response to infection, surgery and injury. The damaged adrenal glands don’t make enough of the hormones causing weakness, weight loss, skin changes and vomiting.
All forms of ALD are caused by a mutation (change) in the ABCD1 gene. This gene makes the ALD protein (ALDP). ALDP helps the peroxisome (small sacs in each of our cells) break down VLCFAs. If there is not enough ALDP, the VCFA’s are not broken down and instead build up. ALDs are the most common type of peroxisomal disorder.
Blood tests detect the buildup of VLCFAs. A brain scan (MRI) can show if myelin is breaking down. If the brain is involved, the disorder may be more progressive and require extensive therapy. Medication and steroids effectively treat Addison’s disease. Many babies are screened for ALD at birth. For more information, visit Baby’s First Test. Research is ongoing, so talk with your doctor about current treatment options. Genetic counselors and support groups are also good sources of information.