Canavan Disease
Canavans disease sets in during early infancy, and usually leads to death by the age of ten years. This form of leukodystrophy causes the white matter of the brain to be replaced by microscopic fluid filled spaces, and is characterised by structural abnormalities and the deterioration of motor, sensory, and intellectual functions. Curiously, this form seems to affect persons of Eastern European Jewish ancestry most frequently.
Feeding difficulties are often the first symptom, followed by progressive mental retardation and apathy. Physical symptoms include muscular flaccidity (floppiness) and weakness, especially in the muscles supporting the head. The brain swells, causing the head to progressively enlarge as the bones of the skull fail to fuse normally. Vision and sometimes hearing may deteriorate due to nerve degeneration, and spasticity and paralysis develop. Mental deterioration progresses with time.
Decreased muscle tone (floppiness) is revealed on neurologic examination, and damage to the optic nerve (optic atrophy). The brain itself is enlarged. Cyst-like spaces pervade the white matter, with large quantities of fluid accumulating in the membranes covering the brain.
The myelin sheath is destroyed in most parts of the brain, as demonstrated by computerized axial tomography (CAT scan), which shows severe white matter changes, and helps to rule out hydrocephalus. Pneumonia may develop due to depressed chest movement while breathing.
Canavans disease can affect both boys and girls, and is inherited through an autosomal recessive mechanism. Excessive amounts of N-acetylaspartic acid in body fluids appear in biochemical testing, as does deficiency of the enzyme aspartoacylase. Carrier detection and prenatal diagnosis are possible through the research efforts and from the laboratory of Dr. Reuben Matalon at the University of Texas in Galveston Texas.
Treatment of Canavans disease is symptomatic, and discomfort may be alleviated by means of supportive care.
Further information can be obtained from:
Canavan Disease [external]