Very late-onset Krabbe disease with concomitant dementia: case description and a critical review of the literature.

backgroundKrabbe disease (KD) is a rare autosomal recessive lysosomal storage disorder caused by pathogenic variants in GALC. Despite accounting only for 5% of forms, reports of adult-onset KD cases are increasingly described.

methodsA female patient manifesting KD after the age of 60 years, presenting with spastic paraplegia and cognitive decline, is described. The scientific literature of KD with onset > 10 years has been extensively reviewed to refine the spectrum of later-onset KD manifestations.

resultsIncluding ours, we identified 84 KD adolescent/adult-onset patients (mean age at onset 28.7 ± 14.2 years). Most patients had limb spasticity as main characterizing neurological feature (58/84, 70.2%), followed by polyneuropathy (11/ 84, 13.1%), both upper and lower motor neuron signs (2/84, 2.4%), and epilepsy (2/84, 2.4%). Five out of 84 patients (6.0%) were asymptomatic. Most patients had cortico-spinal tracts involvement at brain MRI. The most common pathogenic GALC variants were the c.1901 T > C (18 patients), the c.857G > A (13 patients), and the c.1161 + 6532_polyA + 9kbdel (13 patients).

conclusionsComplicated spastic paraplegia is the most common manifestation in later-onset KD, rarely with normal brain MRI. KD should be always considered also in cases with very late-onset spastic paraplegia.