Charcot-Marie-Tooth disease (CMT) is a complex disorder with wide genetic heterogeneity. Here we present a new axonal Charcot-Marie-Tooth disease form, associated with the gene microrchidia family CW-type zinc finger 2 (MORC2). Whole-exome sequencing in a family with autosomal dominant segregation identified the novel MORC2 p.R190W change in four patients. Further mutational screening in our axonal Charcot-Marie-Tooth disease clinical series detected two additional sporadic cases, one patient who also carried the same MORC2 p.R190W mutation and another patient that harboured a MORC2 p.S25L mutation. Genetic and in silico studies strongly supported the pathogenicity of these sequence variants. The phenotype was variable and included patients with congenital or infantile onset, as well as others whose symptoms started in the second decade. The patients with early onset developed a spinal muscular atrophy-like picture, whereas in the later onset cases, the initial symptoms were cramps, distal weakness and sensory impairment. Weakness and atrophy progressed in a random and asymmetric fashion and involved limb girdle muscles, leading to a severe incapacity in adulthood. Sensory loss was always prominent and proportional to disease severity. Electrophysiological studies were consistent with an asymmetric axonal motor and sensory neuropathy, while fasciculations and myokymia were recorded rather frequently by needle electromyography. Sural nerve biopsy revealed pronounced multifocal depletion of myelinated fibres with some regenerative clusters and occasional small onion bulbs. Morc2 is expressed in both axons and Schwann cells of mouse peripheral nerve. Different roles in biological processes have been described for MORC2. As the silencing of Charcot-Marie-Tooth disease genes have been associated with DNA damage response, it is tempting to speculate that a deregulation of this pathway may be linked to the axonal degeneration observed in MORC2 neuropathy, thus adding a new pathogenic mechanism to the long list of causes of Charcot-Marie-Tooth disease.
Background-The influence of age on the main epidemiological, clinical, echocardiographic, microbiological, and prognostic features of patients with infective endocarditis remains unknown. We present the series with the largest numbers and range of ages of subjects to date that analyzes the influence of age on the main characteristics of patients with isolated left-sided infective endocarditis. Furthermore, this series is the first one in which patients have been distributed according to age quartile. Methods and Results-A total of 600 episodes of left-sided endocarditis consecutively diagnosed in 3 tertiary centers were stratified into age-specific quartiles and 107 variables compared between the different groups. With increasing age, the percentage of women, previous heart disease, predisposing disease (diabetes mellitus and cancer), and infection by enterococci and Streptococcus bovis also increased. Valvular insufficiency and perforation and Staphylococcus aureus infection were more common in younger patients. The therapeutic approach differed depending on patient age because of the growing proportion of older patients who only received medical treatment. Clinical course and hospital prognosis were worse in the older patients because of increased surgical mortality among them. Conclusions-Increasing age is associated with less valvular impairment (insufficiency and perforation), a more favorable microbiological profile, and increased surgical mortality among adults with left-sided infective endocarditis. (Circulation. 2010;121:892-897.)
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