ALD - Adrenoleukodystrophy
Adrenoleukodystrophy, or ALD, is a deadly genetic disease that affects 1 in 17,000 people. As it is an X-chromosome linked genetic disease, it most severely affects boys and men (see “Men ALD”, below). This brain disorder destroys myelin, the protective sheath that surrounds the brain’s neurons — the nerve cells that allow us to think and to control our muscles. It knows no racial, ethnic or geographic barriers.
The most devastating form of ALD appears in childhood, generally between the ages of four and ten years old. Normal, healthy boys suddenly begin to regress. At first, they simply show behavioral problems, such as withdrawal or difficulty concentrating, vision problems, or coordination issues. Gradually, as the disease ravages their brain, their symptoms grow worse, including blindness, deafness, seizures, loss of muscle control, and progressive dementia.
This relentless downward spiral leads to a vegetative state or death usually within 2-5 years of diagnosis. Demyelination is the stripping away of the fatty coating that keeps nerve pulses confined and maintains the integrity of nerve signals. This process inhibits the nerves ability to conduct properly, thereby causing neurological deficits. Demyelination is an inflammatory response and nerve cells throughout the brain are destroyed.
AMN - Adrenomyeloneuropathy
The majority of other cases of the disease occur as the adult form of ALD, known as Adrenomyeloneuropathy (AMN). In about half of the sons who inherit the mutated ALD gene, symptoms of the disease do not develop until young adulthood, and in general, they progress more slowly. Beginning in their 20s and 30s, these young men exhibit neurological based motor lesions in their extremities. These lesions progress over many years and are inevitably accompanied by moderate to severe handicap. In approximately one third of these patients the central nervous system also becomes involved. These young men undergo the same mental and physical deterioration as the previously described boys. The progress of the disease is slower, usually declining to a vegetative state and/or death in 5 years or longer.
Addison’s Disease - Hypoadrenocorticism
90% of boys and men with ALD/AMN have Addison’s disease, a disorder of the adrenal gland; in about 10% of ALD cases, this is the only clinical sign of the disorder. The adrenal glands produce a variety of hormones that control levels of sugar, sodium, and potassium in the body, and help it respond to stress. In Addison’s disease, the body produces insufficient levels of the adrenal hormone, which can be life-threatening. Fortunately, this aspect of ALD is easily treated, simply by taking a steroid pill daily (and adjusting the dose in times of stress or illness).
Although women who carry the ALD gene mutation do not generally develop the brain disease itself, some display mild symptoms of the disorder. These symptoms usually develop after age 35, and primarily include progressive stiffness, weakness, or paralysis of the lower limbs, numbness, pain in the joints, and urinary problems.