The ABCC11 gene is known to determine axillary body odor and the type of earwax.[5][18][19][20] The loss of a functional ABCC11 gene is caused by a 538G>A single-nucleotide polymorphism, resulting in a loss of body odor in people who are specifically homozygous for it.[20][21] Firstly, it affects apocrine sweat glands by reducing secretion of odorous molecules and its precursors.[5] The lack of ABCC11 function results in a decrease of the odorant compounds 3M2H, HMHA, and 3M3SH via a strongly reduced secretion of the precursor amino-acid conjugates 3M2H–Gln, HMHA–Gln, and Cys–Gly–(S) 3M3SH; and a decrease of the odoriferous steroids androstenone and androstenol, possibly due to the reduced levels and secretion of DHEAS and DHEA (possibly bacterial substrates for odoriferous steroids).[5] Secondly, it is also associated with a strongly reduced/atrophic size of apocrine sweat glands and a decreased protein (such as ASOB2) concentration in axillary sweat.[5]