Hi @edammer,
We received a question from some investigators who are downloading data from the proteomics-based [ROSMAP subtyping project](syn28722696) for secondary use. They would like to know how the 'JohnsonDx' categories were derived in the [traits file](syn28723027) (i.e. where did the AD/Control/Asymptomatic/Exclude assignments come from?) Can you supply a data dictionary for the traits file, or at least define these terms so we can add them to the wiki for interested data downloaders?
Thanks!
Laura
@asli , @apodder
Created by Laura Heath lheath Yes. That is correct. Each individual in the "Exclude" category has amyloid, tau, and or cognition not fitting within the criteria for AD, AsymAD, or Control cases per the above.
Note it is possible to execute logic using an Excel formula to obtain JohnsonDx. This is demonstrated in a newly uploaded [sample traits file without identifiable information on 1620 autopsied ROSMAP individuals](https://synapse.org/Synapse:syn62784533).
Of 1620 autopsied cases as of November 2019, 271 did not meet JohnsonDx criteria and were labeled by the formula as "Exclude".
Eric Thanks @edammer, that is helpful!
One last question regarding the JohnsonDx category. Just to confirm my assumption: does "Exclude" just mean these individuals had CERAD/BRAAK/cognition criteria that fell outside of the criteria for AD/AsymAD/Control definitions?
Best,
Laura The rubric for case classification was developed with a clinical scientist, Erik C.B. Johnson, first published in Johnson et al, Nat Med, (2020): https://www.nature.com/articles/s41591-020-0815-6
Briefly, here is the relevant methods section. Different cohorts have different measures for cognitive score, but for ROS/MAP it is MMSE.
Methods
Brain tissue samples and case classification
Brain tissue used in this study was obtained from the autopsy collections of the BLSA57, Banner58, MSSB, ACT, Mayo Clinic Brain Bank, ROS/MAP59, University of Pennsylvania School of Medicine Brain Bank and the Baltimore Coroner?s Office. Tissue was from the dorsolateral prefrontal cortex (Brodmann Area 9 where available) or temporal cortex and precuneus regions where indicated. Human postmortem tissues were acquired under Institutional Review Board protocols at each respective institution. Postmortem neuropathological evaluation of neuritic plaque distribution was performed according to CERAD criteria15, while extent of spread of neurofibrillary tangle pathology was assessed with the Braak staging system60. Other neuropathologic diagnoses were made in accordance with established criteria and guidelines61. All case metadata, including age, sex, PMI, cognitive function, APOE genotype, neuropathological criteria and disease status, are provided in Supplementary Table 1. Case classification harmonization across cohorts was performed using the following rubric: cases with CERAD 0?1 and Braak 0?3 without dementia at last evaluation were defined as control (if Braak equals 3, then CERAD must equal 0); cases with CERAD 1?3 and Braak 3?6 without dementia at last evaluation were defined as AsymAD; cases with CERAD 2?3 and Braak 3?6 with dementia at last evaluation were defined as AD. Dementia was defined as MMSE?24, Cognitive Abilities Screening Instrument (CASI) score <81 or CDR???1, based on previous comparative study62.
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