Question

Question Posted 06/29/14:
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 non found subjects?
and how can i reach your 818 ADNI participants( 128 with AD, 415 with MCI, 267 controls)
Response posted 07/07/14 by Sungeun Kim:
ADNI PLINK files use PTIS as an individual ID and other ADNI DB files including DX info file use RID. Therefore, you need to look at "ROSTER.csv" to link PTID to RID. Then, you can find the diagnostic information for all individuals from "DXSUM_PDXCONV_ADNIALL.csv" at baseline visit. However, you may not be able to find DX info for all 818 individuals at some longitudinal visits because some participants skipped some visits and were dropped out during the study due to various reasons.
Response posted 07/08/14 by fayroz:
first of all thanks for your help
I have three questions:
1. WGS SNPs data available in PLink format Version:2014-02-20 has 812 subjects not 818 subjects, there is a mistake in serial numbers(missing serial no: 46, 293, 345, 441, 580, 705)

2. Does genetic data change with exam date or not?

3.I have found more than one diagnosis for the same patient (at different exam dates) and just one genetic code. does it mean sense to take the diagnosis status at last exam date instead of baseline, for the subjects in (WGS SNPs data available in PLink format Version:2014-02-20)
Response posted 07/08/14 by Sungeun Kim:
1. Among 818 WGS samples, 1 was a duplicated sample and 5 couldn't be shared outside the ADNI cores due to limited consents for data sharing. That is the reason that there are 812 individuals.
2. People believe that genetic information is relatively stable compared to other measures. So, you can simple say that genetic data don't change with exam date.
3. ADNI is a longitudinal study following all participants. So, their diagnosis can change over time. Which diagnosis you need to use will totally depend on your questions and testing hypotheses.