Glutamine
Glutamine is the most abundant naturally occurring, nonessential amino acid in the human body, and one of the few amino acids that can directly cross the blood–brain barrier. Humans obtain glutamine through catabolism of proteins in foods they eat. In states where tissue is being built or repaired, like growth of babies, or healing from wounds or severe illness, glutamine becomes conditionally essential.
TMEM249
There exist a number of SNPs for TMEM 249 in humans. The mutations are scattered for the most part, with the largest changes in amino acids occurring in the domain of unknown function.