Earlier work from our laboratory provided evidence for myelin abnormalities (decreased quantities of proteins associated with myelin compaction, decreased sheath thickness) in cortex and hippocampus of Aldh5a1(-/-) mice, which have a complete ablation of the succinate semialdehyde dehydrogenase protein [E.A. Donarum, D.A. Stephan, K. Larkin, E.J. Murphy, M. Gupta, H. Senephansiri, R.C. Switzer, P.L. Pearl, O.C. Snead, C. Jakobs, K.M. Gibson, Expression profiling reveals multiple myelin alterations in murine succinate semialdehyde dehydrogenase deficiency, J. Inher. Metab. Dis. 29 (2006) 143-156]. In the current report, we have extended these findings via comprehensive analysis of brain phospholipid fractions, including quantitation of fatty acids in individual phospholipid subclasses and estimation of hexose-ceramide in Aldh5a1(-/-) brain. In comparison to wild-type littermates (Aldh5a1(+/+)), we detected a 20% reduction in the ethanolamine glycerophospholipid content of Aldh5a1(-/-)mice, while other brain phospholipids (choline glycerophospholipid, phosphatidylserine and phosphatidylinositol) were within normal limits. Analysis of individual fatty acids in each of these fractions revealed consistent alterations in n-3 fatty acids, primarily increased 22:6n-3 levels (docosahexaenoic acid; DHA). In the phosphatidyl serine fraction there were marked increases in the proportions of polyunsaturated fatty acids with corresponding decreases of monounsaturated fatty acids. Interestingly, the levels of hexose-ceramide (glucosyl- and galactosylceramide, principal myelin cerebrosides) were decreased in Aldh5a1(-/-) brain tissue (one-tailed t test, p=0.0449). The current results suggest that lipid and myelin abnormalities in this animal may contribute to the pathophysiology.