Severe deficiency of docosahexaenoic acid in peroxisomal disorders: a defect of delta 4 desaturation?

In confirmation of previous findings, patients with Zellweger's syndrome had extremely low levels of docosahexaenoic acid (22:6 omega 3) in the brain, liver, and kidneys. The other product of delta 4 desaturation, 22:5 omega 6, was also very significantly decreased, as were the ratios 22:6 omega 3/22:5 omega 3 and 22:5 omega 6/22:4 omega 6, especially in the brain and liver of the Zellweger patients. The infant with pseudo-Zellweger's syndrome also had very low levels of 22:6 omega 3 and of the ratio 22:6 omega 3/22:5 omega 3 in all tissues, especially in the brain, where the index 22:5 omega 6/22:4 omega 6 was also very significantly reduced. The ratio 22:6 omega 3/22:4 omega 6 was markedly decreased in all tissues, in Zellweger's as well as in pseudo-Zellweger's syndrome. The findings reported here strongly reinforce the hypothesis of a new enzymatic defect in peroxisomal disorders involving the desaturation of long polyunsaturated fatty acids, especially of the omega 3 family.