MAPT and amyotrophic lateral sclerosis: Furthermore, increased levels of phosphorylated tau protein were observed in patients with limb-onset ALS (median 41.2 ng/l in limb-onset ALS vs. median 29 ng/l in the control group; p = 0.027, post hoc test) and in those with bulbar-onset ALS (median 52.7 ng/l in bulbar-onset ALS vs. median 29 ng/l in the control group; p = 0.005, post hoc test).