= SPONGIFORM LEUKODYSTROPHY

= rare form of leukodystrophy as an autosomal recessive disorder, most common in Ashkenazi Jews

Incidence:<100 reported cases

Cause: deficiency of aspartoacyclase leading to accumulation of N-acetylaspartic acid in brain, plasma, urine, CSF

Histo: spongy degeneration of white matter with astrocytic swelling + mitochondrial elongation

Age: 3–6 months

• marked hypotonia, spasticity, seizures
• progressive megalencephaly
• failure to attain motor milestones, intellectual failure
• optic atrophy with blindness, swallowing impairment
• diffuse symmetric white matter abnormality
• may involve basal ganglia
• cortical atrophy

CT:

• low-density white matter

MR:

• white matter hypointense on T1WI + hyperintense on T2WI

Prognosis: death in 2^nd–5^th year of life

Dx:

1. elevation of N-acetylaspartic acid in urine
2. deficiency of aspartoacyclase in cultured skin fibroblasts