Likewise, stratification of subjects according to their CSF biomarker status, i.e., including only CSF biomarker-negative CN and CSF biomarker-positive MCI and AD individuals), did not result in significant changes in CSF HPX (F = 0.437, p = 0.646), Hbα (F = 0.230, p = 0.795) or Hbβ (F = 0.074, p = 0.929) between diagnostic groups. This evidence concerns the gene HBB and Alzheimer disease.