NFU1 -Related Disorders as Key Differential Diagnosis of Cavitating Leukoencephalopathy.

Genetic leukoencephalopathies represent an expanding group of inherited disorders associated with involvement of brain white matter. Cystic degeneration has been previously described with some acquired or inherited leukoencephalopathies. We describe a 6-month-old Brazilian boy with a 2-month history of severe and rapidly progressive developmental and psychomotor regression and seizures. Neurological examination showed spastic tetraparesis and lethargy. Neuroimaging showed diffuse and symmetric cavitating cystic leukoencephalopathy. Whole-exome sequencing revealed compound heterozygous mutations in the NFU1 gene, providing definite genetic diagnosis of multiple mitochondrial dysfunction syndrome type 1. We report a rare presentation of early-onset cystic leukoencephalopathy in the context of multiple mitochondrial dysfunction syndrome type 1.

Early-onset axonal Charcot-Marie-Tooth disease due to SACS mutation.

Axonal Charcot-Marie-Tooth disease (CMT) represents an expanding group of inherited motor and sensory neuropathies in clinical practice. SACS-gene related disorders have been associated with complex neurological phenotypes of early-onset cerebellar ataxia, spastic-ataxia, spastic paraplegia, demyelinating neuropathy and variable ophthalmological, cognitive and psychiatric disturbances, but never related to pure axonal neuropathy phenotypes. Two unrelated Brazilian men with early-onset axonal CMT-like presentations associated with SACS gene mutations are presented. Both patients presented with pure sensorimotor axonal neuropathy without cerebellar ataxia, spastic paraplegia or other systemic and neurological involvement. Classical neuroimaging findings observed in other sacsinopathies were observed in both cases. Homozygous pathogenic mutations were found in SACS gene in both patients. SACS gene mutations can be associated with pure axonal sensorimotor neuropathy without other neurological features, but with typical neuroimaging features of other sacsinopathies, disclosing the importance of performing neuroimaging studies in patients with suspected axonal CMT.

New genetic causes for complex hereditary spastic paraplegia.

INTRODUCTION: Hereditary Spastic Paraplegia (HSP) represents a complex and heterogeneous group of rare neurodegenerative disorders that share a common clinical feature of weakness and lower limb spasticity that can occur alone or in combination with a constellation of other neurological or systemic signs and symptoms. Although the core clinical feature of weakness and lower limb spasticity is virtually universal, the genetic heterogeneity is almost uncountable with more than 70 genetic forms described so far. We performed review of medical records from twenty-one patients from seventeen Brazilian families with complex phenotype of HSP. All cases have previously negative mutations in SPG11/KIAA1840 and SPG7 gene and were evaluated by whole-exome sequencing. An extensive description of systemic and neurological signs has been described. RESULTS: Whole-exome sequencing was unremarkable in eight patients and established a definite genetic diagnosis in thirteen patients of twelve non-related families. Mutations were found in genes previously implicated in other neurodegenerative disorders such as Amyotrophic Lateral Sclerosis, Hereditary Neuropathy, Spastic Ataxias, Neurodegeneration with Brain Iron Accumulation, Glycogen Metabolism, Congenital Lipodystrophy and aminoacyl-tRNA synthetases disorders. CONCLUSIONS: We report thirteen new genetically-proven cases of complex HSP, expanding the clinical spectrum of presentations of HSP, providing new pathophysiological mechanisms and disclosing new potential therapeutic targets.