# Why microarray expression profile is missing for specific brain structures in the human donors?

**URL:** <https://community.brain-map.org/t/why-microarray-expression-profile-is-missing-for-specific-brain-structures-in-the-human-donors/527>\
**Category:** Technical\
**Tags:** analysis, atlas-human-brain-adult\
**Created:** [April 26, 2020, 11:07am UTC](https://community.brain-map.org/t/why-microarray-expression-profile-is-missing-for-specific-brain-structures-in-the-human-donors/527 "2020-04-26T11:07:58Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Sreekala](https://avatars.discourse-cdn.com/v4/letter/s/ecb155/32.png) [@Sreekala](https://community.brain-map.org/u/Sreekala)\
**Post date:** [April 26, 2020, 11:07am UTC](https://community.brain-map.org/t/why-microarray-expression-profile-is-missing-for-specific-brain-structures-in-the-human-donors/527/1 "2020-04-26T11:07:58Z")

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Hello everyone,  
While trying to analyse the expression profile for individual donors, I realized that the data is missing for specific structures in the brain and this is different in different donors. For example, I found that the expression data for certain hypothalamic structures are missing in donor9861 when compared to other donors. It holds true for other structures in the brain and donors as well.  
On checking the gene correlates, the expression columns for those structures are simply empty.  
Is there a specific reason for these differences? Or these structures were not profiled for those donors?

I appreciate your help!  
Thank you

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**Author:** ![jeremyinseattle](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/jeremyinseattle/32/50_2.png) [@jeremyinseattle](https://community.brain-map.org/u/jeremyinseattle)\
**Post date:** [April 27, 2020, 6:21pm UTC](https://community.brain-map.org/t/why-microarray-expression-profile-is-missing-for-specific-brain-structures-in-the-human-donors/527/2 "2020-04-27T18:21:52Z")

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All structures that were successfully profiled for each donor are included on the website. Some structures (which did not necessarily match between donors) had to be excluded for various technical reasons (e.g., damaged or missing tissue, low quality RNA, etc.).