Impaired FMO3 activity leads to trimethylaminuria, where individuals excrete large amounts of TMA.

“in this abstract, they say impaired FMO3 activity, so FMO3 activity that goes the other direction, gives rise to the inherited disorder trimethylaminuria. Affected individuals cannot produce TMAO, and consequently, excrete large amounts of TMA. Isn't that fascinating? That in this situation, there is actually a congenital known disorder in which people cannot produce TMAO, and it has consequences. They have trimethylaminuria. They have trimethylaminuria, and it probably has many associated bad side effects when you can't actually produce TMAO.”