GRN and frontotemporal dementia: One study identified a missense mutation in a patient with FTD-ALS (p.S120Y) and in a single case of limb onset sporadic ALS (p.T182M) (Schymick et al., 2006), while a later study identified clinical features compatible with MND in 5.4% of patients carrying a GRN mutation; in this cohort, concomitant motor neuron disease was much more common in patients with FTD-TDP pathology not bearing a GRN mutation (26.3%) (Chen-Plotkin et al., 2011).