PTPRQ and early-onset autosomal dominant Alzheimer disease: Recently, Nakajima et al. reported that iNPH patients had significantly higher concentration of the protein tyrosine phosphatase receptor type Q (PTPRQ) in the lumbar CSF (mean: 619 pg/mL), compared with either healthy control individuals (296 pg/mL), patients with Alzheimer’s disease (365 pg/mL) or Parkinson’s disease (338 pg/mL) [100].