Metachromatic leukodystrophy

Alternative names:

MLD

Definition:

An inherited metabolic storage disease characterized by the absence of the enzyme arylsulfatase A and increased storage of sulfatide.

Causes, incidence, and risk factors:

Metachromatic leukodystrophy (MLD) is transmitted as an autosomal recessive trait. MLD has a wide range of symptoms. As with many other storage diseases, there are forms of early and delayed onset (late infant, juvenile and adult types). The most common (and the most severe form) is the late infant onset form, which has symptoms such as irritability, decreased muscle tone, muscle wasting, the loss of the ability to walk. Debility is progressive with blindness, seizures, and partial paralysis. Death occurs usually before age 10.

Both the juvenile and adult forms have later onset but similar symptoms. In the adult and juvenile forms, psychosis and emotional disturbances are an important part of the illness. The juvenile form is fatal within a few years of diagnosis. The adult form may be drawn out over many years.