Proportions of various straight and branched fatty acid chain types in the sebaceous wax esters of young children.

The fatty acid composition of sebaceous wax esters was examined in 20 children, ages 6-8, using quartz capillary gas chromatography. The results were compared with a previously reported study of wax ester composition in 10 adults, in which the same analytical techniques were used. The children's wax esters showed more variability in the proportions of all fatty acid chain types than was found in adults. The most striking difference between the 2 age groups was in the proportions of iso-branched fatty acids with odd numbers of carbon atoms. These ranged from 1-26% of fatty acids in the children's wax esters but were not more than 3% of fatty acids in the adults' wax esters. Some of the variability in wax ester fatty acid composition in children seemed to be related to variation in rates of sebum production. The highest percentages of terminally branched (iso-even, iso-odd, and anteiso) and the lowest percentages of internally branched fatty acids were found in the children with the lowest rates of sebum secretion. However, even in children with similar rates of sebum secretion there were considerable differences in wax ester fatty acid composition, especially with respect to iso-even fatty acids. The results suggest that sebum fatty acid composition is influenced both by genetic factors and by limitations on the supply of precursors for terminally branched, but not internally branched, fatty acids.