Table 1. Biochemical and enzymology analyses.

Plasma VLCFA	Patient 1	Patient 2	Unaffected reference range	X-ALD hemizygote reference range	Zellweger syndrome reference range
C26:0 (μg/ml)	2.22*	1.04*	0.24±0.14	1.30±0.45	3.93±1.50
C26:1 (μg/ml)	1.13*	1.69*	0.11 ±0.04	0.34±0.16	4.08±2.30
C26/C22 ratio	0.11*	0.12*	0.01±0.003	0.07±0.03	0.50±0.16
C24/C22 ratio	1.582*	1.284*	0.78±0.10	1.71±0.23	2.07±0.28
Phytanic acid (μg/ml)	0.47	0.04	0.54±0.29	0.57±0.46	0.40±0.28
Pristanic acid (μg/ml)	0.04	0.05	0.05±0.04	0.06±0.06	0.09±0.16
Fibroblast studies
Phytanic acid oxidation (pmol/48 h/mg protein)	832.3		942.6±111.4
C26:1 (μg/mg protein)	0.537*		0.09±0.07
C26:0 (μg/mg protein)	0.448*		0.07±0.04
C22:0 (μg/mg protein)	0.33*		0.90±0.40
C26:0/C22:0	1.355*		0.08±0.03
C16 oxidation capacity (nmol/hr/mg prot)	1.67		1.68
C24 oxidation capacity (nmol/hr/mg prot)	0.11*		0.29
C24:C16 oxidation ratio	0.068*		0.17
Neural stem cell studies
C16 oxidation capacity (pmol/hr/mg protein)	703		1336
C24 oxidation capacity (pmol/hr/mg protein)	255*		981
C24:C16 oxidation ratio	0.362*		0.739

Plasma VLCFA levels and ratios were elevated in both patients compared to normal, above the ranges of X-ALD hemizygotes and below the ranges seen in Zellweger syndrome. Phytanic and pristanic acid levels were normal. β-Oxidation of [1-¹⁴ C]C16:0 or [1-¹⁴ C]C24:0 in skin fibroblasts or neural stem cells demonstrated intact mitochondrial long chain fatty acid oxidation but defective peroxisomal oxidation of C24:0 VLCFA in both fibroblasts and neural stem cells from patient 1. Abnormal values are highlighted with asterisks