To elucidate the mechanisms underlying the phenotypic variability of ALD, we studied the expression of ABCD1, three other peroxisomal transporter genes of the same family (ABCD2, ABCD3 and ABCD4) and two VLCFA synthetase genes (VLCS and BG1) involved in VLCFA metabolism, as well as the VLCFA concentrations in the normal white matter (WM) from ALD patients with CCER, AMN-C and AMN phenotypes.
X-linked adrenoleukodystrophy in Spain. Identification of 26 novel mutations in the ABCD1 gene in 80 patients. Improvement of genetic counseling in 162 relative females.
In mice, ABCD1 loss causes late onset axonal degeneration in the spinal cord in association with locomotor disability resembling the most common phenotype in patients, adrenomyeloneuropathy.
We assessed spinal cord microglia in humans and mice with AMN and investigated the role of ABCD1 in microglial activity toward neuronal phagocytosis in cell culture.
We combined an untargeted metabolome assay of plasma and peripheral blood mononuclear cells (PBMC) of AMN patients, which used liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (LC-Q-TOF), with a functional genomics analysis of spinal cords of Abcd1(-) mouse.
Pipecolic acid was elevated, often markedly, in most of the patients with NALD but in none of those with X-linked ALD or adrenomyeloneuropathy, or in normal adults and children, or children with cirrhosis or other neurodegenerative disorders.
In the mouse, Abcd1 loss causes late onset axonal degeneration in the spinal cord, associated with locomotor disability resembling the most common phenotype in patients, adrenomyeloneuropathy.
Among adult X-ALD phenotypes, the myo-inositol to creatine ratio was 46% higher and the choline to creatine ratio was 21% higher in normal-appearing white matter of those with adult cerebral ALD compared with those with AMN (P < .05).
Moreover, the normal oxidation of lignoceroyl-CoA as compared with the deficient oxidation of lignoceric acid in isolated peroxisomes also supports the conclusion that peroxisomal lignoceroyl-CoA ligase is impaired in both C-ALD and AMN.
To gain insights into these questions, we undertook a transcriptomic approach followed by a functional-enrichment analysis in spinal cords of the animal model of AMN, the Abcd1(-) null mice, and in normal-appearing white matter of cAMN and cALD patients.
Incidence of Abcd1 level on the induction of cell death and organelle dysfunctions triggered by very long chain fatty acids and TNF-α on oligodendrocytes and astrocytes.
The disruptive nature of two mutations (i.e., the frameshift and the nonsense mutation) in patients with biochemically proved childhood ALD and AMN further strongly supports the hypothesis that alterations in this gene play a crucial role in the pathogenesis of X-ALD.
The two main clinical phenotypes of X-ALD are adrenomyeloneuropathy (AMN) and inflammatory cerebral ALD that manifests either in children or more rarely in adults.
The two most common forms of X-linked adrenoleukodystrophy (X-ALD), the childhood cerebral form (CCER) and the adult form, adrenomyeloneuropathy (AMN), arise from the same mutations in the X-ALD gene at Xq28.
ABCD1 mutations lead to a variety of phenotypes, including cerebral X-ALD and adrenomyeloneuropathy (AMN) in affected males and 80% of carrier females.
The nearly complete novel spectrum of ALD gene mutations identified has revealed no obvious correlation between the type of mutation and age of AMN onset in this small series.