Peripheral nerve enlargement on nerve ultrasound parallels neuropathological changes in adult-onset Krabbe disease

Adult-onset Krabbe disease presenting with progressive myoclonic epilepsy and asymmetric occipital lesions: A case report

Krabbe disease (KD), also known as globoid cell leukodystrophy, is a rare autosomal recessive condition caused by mutations in the galactocerebrosidase (GALC) gene. KD is more common in infants and young children than in adults. We reported the case of an adult-onset KD presenting with progressive myoclonic epilepsy (PME) and cortical lesions mimicking mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. The whole-exome sequencing (WES) identified a pathogenic homozygous missense mutation of the GALC gene. Parents of the patient were heterozygous for the mutation. The clinical, electrophysiological, and radiological data of the patient were retrospectively analyzed. The patient was a 24-year-old woman presenting with generalized seizures, progressive cognitive decline, psychiatric symptoms, gait ataxia, and action-induced myoclonus. The brain magnetic resonance imaging (MRI) revealed a right occipital cortical ribbon sign without any other damage. This single case expands the clinical phenotypes of adult-onset KD.

Hereditary neuropathies: A pathological perspective

Hereditary neuropathies may result from mutations in genes expressed by Schwann cells or neurons that affect selectively the peripheral nervous system (PNS) or may represent a minor or major component of complex inherited diseases that involve also the central nervous system and/or other organs and tissues. The chapter is constantly expanding and reworking, thanks to advances of molecular genetics; next-generation sequencing is identifying a plethora of new genes and is revolutionizing the diagnostic approach. In the past, diagnostic sural nerve biopsies paved the way to the discovery and elucidation of major genes and molecular pathways associated to most frequent hereditary motor-sensory neuropathies. Nowadays, a sural nerve biopsy may prove useful in selected cases for the differential diagnosis of an acquired neuropathy when clinical examination, nerve conduction studies, and molecular tests are not sufficiently informative. Skin biopsy has emerged as a minimally invasive window on the PNS, which may provide biomarkers of progression and clues to the physiopathology and molecular pathology of inherited neuropathies. The aim of our review is to illustrate the pathological features of more frequent and paradigmatic hereditary neuropathies and to highlight their correlations with the roles of the involved genes and functional consequences of related molecular defects.