Body odor is usually normal, but when it's extreme it can be a sign of something gone wrong.
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Sources:
Trimethylaminuria
https://ghr.nlm.nih.gov/condition/trimethylaminuria
https://rarediseases.org/rare-diseases/trimethylaminuria/
http://dmd.aspetjournals.org/content/29/4/517.short
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848652/
http://www.bmj.com/content/307/6917/1497.5
http://jamanetwork.com/journals/jamadermatology/fullarticle/410589
http://omim.org/entry/136132
https://www.ncbi.nlm.nih.gov/books/NBK1103/

Isovaleric acidemia
https://ghr.nlm.nih.gov/condition/isovaleric-acidemia
https://rarediseases.org/rare-diseases/acidemia-isovaleric/
http://www.omim.org/entry/243500
http://newenglandconsortium.org/for-professionals/acute-illness-protocols/organic-acid-disorders/isovaleric-acidemia/
https://www.ncbi.nlm.nih.gov/pubmed/19210957
https://www.ncbi.nlm.nih.gov/pubmed/3137519

Hypermethioninemia
https://ghr.nlm.nih.gov/condition/hypermethioninemia
http://www.sciencedirect.com/science/article/pii/S1096719213002710
http://www.omim.org/entry/250850
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1288087/
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"Mister Exposition" Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
http://creativecommons.org/licenses/by/3.0/
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Images:
https://commons.wikimedia.org/wiki/File:Trimethylamine-3D-balls.png
https://commons.wikimedia.org/wiki/File:L-Leucine.svg
https://commons.wikimedia.org/wiki/File:Isovalerians%C3%A4ure.svg
https://commons.wikimedia.org/wiki/File:Sulfur-sample.jpg
https://commons.wikimedia.org/wiki/File:Nervous_system_diagram_unlabeled.svg