C9orf72 and mild neurocognitive disorder: Except for 4 subjects with C9orf72 mutations presenting with motor neuron disease (MND) [37, 85] and another 2 subjects also with C9orf72 mutations presenting with MD and MND [82, 85], all subjects with movement symptoms at onset presented with a movement disorder including clinical syndromes of Parkinsonism, CBS or PSPS.