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Charcot Marie Tooth (CMT) due to myelin protein zero (MPZ) mutations, may cause a wide variation of phenotypes, depending on the localization of the mutation within the gene. Among the most common phenotypes are: an infantile onset disease with extremely slow nerve conduction velocities (CMT1B) and an adult onset phenotype with nerve velocities in the axonal range (CMT2I). We reported a patient with CMT1B (MPZ p.Ser63del mutation) which developed an overlapping immune mediated polyradiculoneuropathy with recurrent episodes of quadriparesis and cranial nerve involvement. We observed reversible conduction block on serial neurophysiologic studies, non-uniform demyelination and good clinical response to prednisone and cyclophosphamide, as evidenced by objective functional recovery. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)-like characteristics have not yet been described associated with a MPZ p.Ser63del mutation. This description adds evidence indicating that a defective structural myelin protein may predispose peripheral nerves to immune attacks.

Leigh syndrome represents a complex inherited neurometabolic and neurodegenerative disorder associated with different clinical, genetic and neuroimaging findings in the context of bilateral symmetrical lesions involving the brainstem and basal ganglia. Heterogeneous neurological manifestations such as spasticity, cerebellar ataxia, dystonia, choreoathetosis and parkinsonism are associated with multisystemic and ophthalmological abnormalities due to >75 different monogenic causes. Here, we describe the clinical and genetic features of a Brazilian cohort of patients with Leigh Syndrome in which muscle biopsy analysis showed mitochondrial DNA defects and determine the utility of whole exome sequencing for a final genetic diagnostic in this cohort.

An 11-year-old Brazilian boy presented with worsening left thigh weakness. At age 2 years, he presented with left lower limb weakness after 4 days of a severe asthma episode. Examination showed amyotrophy, weakness, and areflexia of the left lower limb (figure). Spine MRI and CSF analysis (including serology and PCR for herpesvirus, enterovirus, and arbovirus) were unremarkable. Neurophysiologic studies exhibited ongoing denervation and chronic reinnervation changes involving the left lower limb muscle groups. Our patient was diagnosed with Hopkins syndrome, a rare childhood-onset lower motor neuron disease presenting with monomelic amyotrophy after an acute asthma attack.1,2

Atypical motor neurone disease (MND) represents a challenging and expanding group of neurodegenerative disorders involving the upper or lower motor neurones, and rarely both. Neuro-ophthalmological disturbances such as gaze-evoked downbeat nystagmus are extremely rare in the context of typical and atypical MND. Finger extension weakness and downbeat nystagmus motor neurone disease (FEWDON-MND) syndrome has been recently recognised as a distinct syndromic phenotype of MND, with a characteristic clinical picture. We describe a 63-year-old woman with long-standing lower motor neurone involvement of the upper limbs, who on examination had gaze-evoked downbeat nystagmus. After extensive negative investigation for secondary causes of MND and downbeat nystagmus, we diagnosed FEWDON-MND syndrome.

Background Hypomyelinating leukodystrophies represent an expanding group of neurogenetic disorders characterized primarily by central nervous system hypomyelination and variable neurological and non-neurological involvement. Hypomyelinating disorders have been rarely associated with gonadal dysfunction, being mainly represented by hypogonadotrophic hypogonadism in 4H syndrome. WT1 gene-associated disorders are classically associated with complex phenotypes including early carcinogenic risk for gonadoblastoma and Wilms' tumor, chronic renal failure, nephrotic syndrome and sex developmental disorders in intersex disorders and ambiguous genitalia. Methods The authors describe three non-related Brazilian patients with hypomyelinating leukodystrophy associated with complex neurological and systemic dysfunction with WT1 gene mutations. Results All described patients presented with similar neuroimaging features including thin corpus callosum, mild to moderate cerebellar atrophy and diffuse periventricular and profound hypomyelinating leukodystrophy involving supratentorial white matter with classical compromise linked to inherited non-somatic WT1 gene mutations in a similar pattern to Denys-Drash syndrome, including nephrotic syndrome with different glomerular disease, chronic renal failure, intersex disorder with ambiguous genitalia, and early occurrence of specific tumors, such as Wilms' tumor and gonadoblastoma. Conclusions Clinicians must include WT1 gene mutations in the differential diagnosis of hypomyelinating leukodystrophy with nephrotic syndrome, chronic renal failure, ambiguous genitalia or sex developmental disorders.