Normal composition of the major lipids and the distribution of their fatty acids in central nervous system myelin further discriminate mld from shiverer mice.

The primary defect in myelin deficiency (mld), an autosomal recessive mutation in mice with severe hypomyelination of the central nervous system (CNS), is a reduction in the synthesis of myelin basic protein (MBP) due to reduced amounts of MBP-specific mRNA. The present study was performed to determine whether alterations of myelin lipid composition might be associated with this defect. Although a 20-fold reduction of myelin was found in mld brain, the lipid/protein and the phospholipid/sulfatide ratios of purified myelin were unchanged. The analysis of polar lipids demonstrated no striking difference. However, phosphatidylethanolamine (including plasmalogens of the ethanolamine type) was decreased by 7.7% in mld. Fatty acids of total and polar lipids (phospholipids + glycolipids) exhibited a slight decrease in 20:1(n-11) and 20:1(n-9). In conclusion, these results further differentiate mld from its allele shiverer, which shares with mld a dramatic reduction of MBP and absence of major dense line but, in contrast, presents other important biochemical differences in CNS myelin.