03507nas a2200517 4500008004100000022001400041245007400055210006900129260001300198300001000211490000800221520209300229653001002322653000902332653001202341653001002353653003202363653001102395653002002406653001102426653001102437653000902448653000902457653001602466653001302482653001302495653001402508653001802522653001602540653002602556653001602582100002002598700001902618700002902637700001802666700001902684700002502703700002402728700003102752700001802783700002002801700002202821700002002843700002102863856010502884 2016 eng d a1460-215600aMutations in the MORC2 gene cause axonal Charcot-Marie-Tooth disease.0 aMutations in the MORC2 gene cause axonal CharcotMarieTooth disea c2016 Jan a62-720 v1393 a
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.
10aAdult10aAged10aAnimals10aAxons10aCharcot-Marie-Tooth Disease10aFemale10agene expression10aHumans10aInfant10aMale10aMice10aMiddle Aged10amutation10aPedigree10aPhenotype10aSciatic Nerve10aSural Nerve10aTranscription Factors10aYoung Adult1 aSevilla, Teresa1 aLupo, Vincenzo1 aMartínez-Rubio, Dolores1 aSancho, Paula1 aSivera, Rafael1 aChumillas, María, J1 aGarcía-Romero, Mar1 aPascual-Pascual, Samuel, I1 aMuelas, Nuria1 aDopazo, Joaquin1 aVílchez, Juan, J1 aPalau, Francesc1 aEspinós, Carmen uhttps://www.clinbioinfosspa.es/content/mutations-morc2-gene-cause-axonal-charcot-marie-tooth-disease