A novel mutation in the ABCD1 gene causes adrenomyeloneuropathy by impairing autophagy level / 中华神经科杂志

ABSTRACT

Objective:To report a Chinese family with a novel ABCD1 gene mutation at c.332T>G (p.V111G) site and discuss its clinical characteristics and molecular mechanism.Methods:The clinical data, laboratory examination, and imaging examination results were analyzed to make the clinical diagnosis of a middle-aged onset patient from the First Affiliated Hospital of Zhengzhou University in May 2017. High-throughput sequencing was used to discover a novel ABCD1 gene mutation. Sanger sequencing was used to find out whether other family members contain the same ABCD1 gene mutation. The pathogenicity of this mutation was explored by protein structure prediction and pathogenicity analysis. Adrenoleukodystrophy protein-green fluorescent protein (ALDP-GFP) and ALDP-GFP (V111G) plasmids were constructed and human embryonic kidney 293 cells were transfected, then immunofluorescence and Western blotting were used to explore the molecular mechanism of this mutation (completed in Henan Provincial People′s Hospital).Results:The proband (a 39-year-old male) was diagnosed as adrenomyeloneuropathy, a subset of X-linked adrenoleukodystrophy, with a novel heterozygous missense mutation in the ABCD1 gene at c.332T>G (p.V111G) site, and his mother and two daughters were all carriers. Protein structure prediction and pathogenicity results suggested that this mutation is pathogenic. Overexpression of ALDP-GFP (V111G) in the human embryonic kidney 293 cells resulted in a significant decrease in the expression levels of ALDP and the abnormal localization from the peroxisomal membrane to the cytoplasm, accompanied by significant down-regulation of LC3-Ⅱ/LC3-Ⅰ and beclin-1.Conclusion:c.332T>G (p.V111G) is a novel pathogenic mutation in the ABCD1 gene, which causes adrenomyeloneuropathy by impairing autophagy.