Clinical manifest x-linked recessive adrenoleukodystrophy in a female

Eight novel mutations in the ABCD1 gene and clinical characteristics of 25 Chinese patients with X-linked adrenoleukodystrophy

BACKGROUND

X-linked adrenoleukodystrophy (X-ALD) is a fatal neurodegenerative disease caused by mutations in the adenosine triphosphate-binding cassette D1 (ABCD1) gene. This study aimed to retrospectively investigate the clinical characteristics of 25 patients with X-ALD including members of large pedigrees, to analyze ABCD1 gene mutations, the effect of gene novel variants on ALD protein (ALDP) structure and function, and to expand gene mutation spectrum of Chinese patients.

METHODS

Twenty-five male patients diagnosed with X-ALD were enrolled in this study. The clinical characteristics of the patients were retrospectively summarized by reviewing medical records or telephone consultation. ABCD1 gene mutations were analyzed. The pathogenicity of novel missense variants was analyzed using cobalt constraint-based multiple protein alignment tool, polymorphism phenotyping, sorting intolerant from tolerant, Align-Grantham variation and Grantham deviation, and Swiss-Program Database Viewer 4.04 software, respectively.

RESULTS

Childhood cerebral form ALD (CCALD) is the most common phenotype (64%) in the 25 patients with X-ALD. The progressive deterioration of neurological and cognitive functions is the main clinical feature. The demyelination of the brain white matter and elevated plasma very long chain fatty acids (VLCFAs) were found in all patients. Different phenotypes were also presented within family members of the patients. Twenty-two different mutations including 8 novel mutations in the ABCD1 gene were identified in the 25 patients. Of the mutations, 63.6% were missense mutations and 34.8% located in exon 1. The amino acid residues of three novel missense mutations in eight species were highly conserved, and were predicted to be "probably" damaging to ALDP function. The other five novel mutations were splice, nonsense, deletion or duplication mutations.

CONCLUSIONS

CCALD is the most common phenotype (64%) in our patients with X-ALD. Eight novel mutations in the ABCD1 gene identified are disease-causing mutations. Brain magnetic resonance imaging and plasma VLCFA determination should be performed for the patients who present with progressive deterioration of neurological development.

X-linked adrenoleukodystrophy presenting as attention deficit hyperactivity disorder

X-linked adrenoleukodystrophy (X-ALD) is one the leukodystrophies causing a progressive decline in neurological function mainly affecting the children. The most common symptoms are changes in behavior, including social withdrawal or aggression, poor memory or poor scholastic performance. Here, we present a 7-year-old boy who presented with symptoms of inattention and hyperactivity and later turned out to be a case of X-ALD.