Leigh's Disease

Leigh's disease is an inherited metabolic disorder that damages the central nervous system (brain, spinal cord, and optic nerves). Leigh's disease is caused by problems in the mitochondria, the energy centers in the body's cells.

A genetic disorder that causes Leigh's disease can be inherited in three different ways. It may be inherited on the X (female) chromosome as a genetic deficiency of an enzyme called pyruvate dehydrogenase complex (PDH-Elx).

It may be inherited as an autosomal recessive condition that affects the assembly of an enzyme called cytochrome-c-oxidase (COX). It may also be inherited as a mutation in the DNA in the cell mitochondria.

Symptoms

The symptoms of Leigh's disease usually begin between the ages of 3 months and 2 years. Since the disease affects the central nervous system, symptoms may include:

• poor sucking ability
• difficulty holding up the head
• losing motor skills the infant had such as grasping a rattle and shaking it
• loss of appetite
• vomiting
• irritability
• continuous crying
• seizures

As Leigh's disease becomes worse over time, the symptoms may include:

• generalized weakness
• lack of muscle tone (hypotonia)
• episodes of lactic acidosis (accumulation of lactic acid in the body and brain) that may impair breathing and kidney function
• heart problems

Diagnosis

Diagnosis of Leigh's disease is based on the symptoms the infant or child has.

Tests may show a deficiency of pyruvate dehydrogenase or the presence of lactic acidosis. Individuals with Leigh's disease may have symmetrical patches of damage in the brain that may be discovered by brain scan. In some individuals, genetic testing may be able to identify the presence of a genetic mutation.

Treatment

Treatment of Leigh's disease usually includes vitamins such as thiamine (vitamin B1). Other treatments may focus on the symptoms present, such as anti-seizure drugs or heart or kidney medicines. Physical, occupational, and speech therapy can help a child reach his or her developmental potential.

_Sources:

"NINDS Leigh's Disease Information Page." Disorders. 13 Feb 2007. National Organization for Neurological Disorders and Stroke.

"Leigh's Disease." Index of Rare Diseases. 17 Dec 2007. National Organization for Rare Disorders.

Macnair, Trisha. "Leigh's Disease." BBC Health. July 2006.