It is characterized by early-onset enlargement of the head (macrocephaly) as well as delayed-onset neurological deterioration to include spasticity, epilepsy, and lack of muscular coordination.
Other significant central nervous system symptoms include diffuse spongiform leukoencephalopathy and vacuolizing myelinopathy.
In vacuolizing myelinopathy, the protective myelin sheath on neurons pulls away from their cells, forming small holes in nerve fibers.
[citation needed] Diagnosis of Megalencephalic leukoencephalopathy with subcortical cysts is made with a combination of physical and clinical evaluations.
[11] In the late stages of the disease, patients have been noted to develop impaired coordination, overresponsive reflexes, and even seizures.
A study conducted on four patients with this disease yielded similar MRI results despite their slightly differing symptoms.
[13] Nonetheless, Megalencephalic leukoencephalopathy with subcortical cysts does not show genetic heterogeneity which means that there are no mutations in other loci expressing similar phenotypes.
[citation needed] A series of cases with megalencephalic leukodystrophy were described by the Indian neurologist Bhim Sen Singhal (1933-)in 1991.