Alpha Mannosidosis

Definition

Definition of Alpha Mannosidosis
Alpha-mannosidosis is a lysosomal storage disorder caused by deficient activity of the enzyme alpha-D-mannosidase (see Alpha-Mannosidase). In humans it is known to be caused by an autosomal recessive genetic mutation. In livestock it is caused by chronic poisoning with swainsonine (see Locoweed).

Symptoms

Symptoms of Alpha Mannosidosis
Symptoms range widely in their onset and severity. The onset of the most severe form, type III, begins within the first months of life and includes a quick progression of mental retardation, liver and spleen enlargement (splenomegaly), hearing loss, respiratory infections and skeletal abnormalities. Often the appearance of an affected individual includes the following facial features: protruding forehead, leveled nasal bridge, small nose and wide mouth. Muscular weakness or spinal abnormalities can occur due to the build up of storage materials in the muscle. A milder form of Alpha-mannosidosis involves mild to moderate mental retardation which develops during childhood or adolescence.

Causes

Causes of Alpha Mannosidosis
Alpha-mannosidosis is a rare inherited disorder that causes problems in many organs and tissues of the body.

Diagnosis

Diagnosis of Alpha Mannosidosis
A diagnosis is made by measuring the enzymatic activity of alpha-D-mannosidase in white blood cells. If there is a decreased level of the enzyme in comparison to standard levels, a diagnosis can be made. It is thought that this disorder might be under-diagnosed for a few different reasons - the diagnosis is often made late in the disease's progression, symptoms are often mild, or the biochemical diagnosis does not yield conclusive results.

Treatment

Treatment of Alpha Mannosidosis
There is no cure for congenital Alpha-Mannosidosis. Treatment is limited to reducing or controlling the symptoms of this disorder by, for example, taking medication to control seizures, using a hearing aid to assist with hearing loss, and by having routine physical therapy to assist with muscular pain and weakness. In some cases, a wheelchair is recommended if muscle or spinal impairments immobilize the individual affected. Despite early reports to the contrary, bone marrow transplants performed at an early age have shown promise in halting the progression of this disorder.

Prognosis

Prognosis of Alpha Mannosidosis
The long-term prognosis is poor. There is an insidiously slow progression of neuromuscular and skeletal deterioration over several decades, making most patients wheel-chair dependent. No patients manage to be completely socially independent. Many patients are over 50 years of age.

Prevention

Prevention of Alpha Mannosidosis
Consult with your doctor.