Early infantile Krabbe disease: deceptively normal magnetic resonance imaging and serial neurophysiological studies

Early infantile Krabbe disease is a progressive neurodegenerative disease caused by deficiency of lysosomal enzyme galactocerebroside β-galactosidase, with onset before the age of 6 months. We present serial clinical, radiological and neurophysiological findings of a patient with early infantile Krabbe disease, presenting at the third day of life with hypotonia, macrocephaly and neonatal seizures. The patient had a deceptively normal initial magnetic resonance imaging examination at the age of 3 months, with progression of the white matter disease over the following 9 months, showing a clinical picture of profound hypotonia with pyramidal and pseudobulbar signs, as well as mild optic atrophy. Assay of galactocerebroside β-galactosidase activity in leukocyte culture disclosed a marked deficiency of the enzyme (0.00 nmol/mg protein per h with normal values >0.7 nmol/mg protein per h), thus confirming the diagnosis of Krabbe disease. Nerve conduction velocity and evoked potential studies, as well as the electroencephalogram, were abnormal at the age of 6 months, while serial neurophysiological studies at the age of 12 and 18 months demonstrated the progressive nature of the disease.