Question

Question Posted 06/30/14:
I downloaded the plink data(812) with missing phynotype and after linking it with clinical data(879) to know AD,MCI and control subjects, i don't found 495 subjects and found 281 subjects out of 812 normal, 21 subjects out of 812 AD and 15 subjects out of 812 MCI .
can you explain why i did not find subjects?
and how can i reach your 818 ADNI participants( 128 with AD, 415 with MCI, 267 controls)
Response posted 06/30/14 by Sungeun Kim:
ADNI PLINK files use patient ID (PTID) as an individual ID (IID) and other ADNI data files use RID. So, in order to link PTID to RID, you need to look at "Roster.csv" and can find all available DX information from "DXSUM_PDXCONV_ADNIALL.csv". You should be able to find DX information for all 818 individuals at the baseline visit. However if you want DX at any longitudinal visit, you may not be able to get it for all 818 individuals because some individuals skipped certain visits and dropped out from the study during the follow-up.