A Japanese family with adrenoleukodystrophy with a codon 291 deletion: a clinical, biochemical, pathological, and genetic report

Brainstem dominant form of X-linked adrenoleukodystrophy with a novel ABCD1 missense variant: A case report and literature review

BACKGROUND

X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder attributed to ABCD1 mutations. Case reports with predominant brainstem involvement are rare.

CASE PRESENTATION

In this study, we reported a plateau male worker of X-ALD characterized by progressive weakness accompanied by gait instability, mild nystagmus, and constipation. After 2 years of onset, a brain Magnetic Resonance Image (MRI) scan showed no abnormality but genetic analysis revealed a heterozygous mutation (c.1534G>A) in the ABCD1 gene. After 7 years of onset, although the patient was given aggressive dietary and symptomatic treatment in the course of the disease, a brain MRI scan showed predominantly brainstem damage, but serum concentrations of very long-chain fatty acids were normal, and he had been bedridden for almost 2 years with severe bladder dysfunction, forcing him to undergo cystostomy. The patient was discharged with improved urinary retention and renal function.

CONCLUSIONS

We reported an X-ALD patient with a novel ABCD1 variation characterized by brainstem damage and retrospectively summarized the clinical manifestation, MRI features, and genetic features of X-ALD patients with brainstem damage.

S149R, a novel mutation in the ABCD1 gene causing X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder. It is a heterogeneous disorder caused by mutations in the ATP-binding cassette protein subfamily D1 (ABCD1) gene, encoding the peroxisomal membrane protein ALDP, which is involved in the transmembrane transport of very long-chain fatty acids. For the first time, we report a case of olivopontocerebellar X-ALD on the Chinese mainland. In this study, a novel mutation (c.447T>A; p.S149R) in ABCD1 was detected in a patient diagnosed with X-ALD. The mutant amino acid is well conserved among species. Bioinformatics analysis predicted the substitution to be deleterious and to cause structural changes in the adrenoleukodystrophy protein. Immunofluorescence showed an altered subcellular localization of the S149R mutant protein, which may lead to defects in the degradation of very long chain fatty acids in peroxisomes. We therefore suggest that the novel mutation, which alters ALDP structure, subcellular distribution and function, is responsible for X-ALD.

Unmasking adrenoleukodystrophy in a cohort of cerebellar ataxia

Adrenoleukodystrophy (ALD) is a rare and progressive neurogenetic disease that may manifest disparate symptoms. The present study aims at investigating the role of ataxic variant of ALD (AVALD) in patients with adult-onset cerebellar ataxia, as well as characterizing their clinical features that distinguish AVALD from other cerebellar ataxias. Mutations in the ATP binding cassette subfamily D member 1 gene (ABCD1) were ascertained in 516 unrelated patients with ataxia. The patients were categorized into three groups: molecularly unassigned hereditary ataxia (n = 118), sporadic ataxia with autonomic dysfunctions (n = 296), and sporadic ataxia without autonomic dysfunctions (n = 102). Brain MRIs were scrutinized for white matter hyperintensity (WMH) in the parieto-occipital lobes, frontal lobes, corticospinal tracts, pons, middle cerebellar peduncles and cerebellar hemispheres. Two ABCD1 mutations (p.S108L and p.P623fs) previously linked to cerebral ALD and adrenomyeloneuropathy but not AVALD were identified. ALD accounts for 0.85% (1/118) of the patients with molecularly unassigned hereditary ataxia and 0.34% (1/296) of the patients with sporadic ataxia with autonomic dysfunctions. WMH in the corticospinal tracts and WMH in the cerebellar hemispheres were strongly associated with AVALD rather than other ataxias. To conclude, ALD accounts for approximately 0.39% (2/516) of adult-onset cerebellar ataxias. This study expands the mutational spectrum of AVALD and underscores the importance of considering ALD as a potential etiology of cerebellar ataxia.

Adult-onset cerebello-brainstem dominant form of X-linked adrenoleukodystrophy presenting as multiple system atrophy: case report and literature review

X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder and is caused by ABCD1 mutations. A cerebello-brainstem dominant form that mainly involves the cerebellum and brainstem is summarized in a review of the literature, with autopsy-confirmed cases exceedingly rare. We report a 69-year-old White man who was diagnosed with this rare disorder and describe neuropathologic, ultrastructural and genetic analyses. He did not have adrenal insufficiency or a family history of X-ALD or Addison's disease. His initial symptom was temporary loss of eyesight at age 34 years. His major symptoms were chronic and progressive gait disorder, weakness in his lower extremities and spasticity, as well as autonomic failure and cerebellar ataxia suggesting possible multiple system atrophy (MSA). He also had seizures, hearing loss and sensory disturbances. His brain MRI showed no obvious atrophy or significant white matter pathology in cerebrum, brainstem or cerebellum. He died at age 69 years with a diagnosis of MSA. Microscopic analysis showed mild, patchy myelin rarefaction with perivascular clusters of PAS-positive, CD68-positive macrophages in the white matter most prominent in the cerebellum and occipital lobe, but also affecting the optic tract and internal capsule. Electron microscopy of cerebellar white matter showed cleft-like trilamellar cytoplasmic inclusions in macrophages typical of X-ALD, which prompted genetic analysis that revealed a novel ABCD1 mutation, p.R163G. Given the relatively mild pathological findings and long disease duration, it is likely that the observed pathology was the result of a slow and indolent disease process. We described a patient who had sporadic cerebello-brainstem dominant form of X-ALD with long clinical course, mild pathological findings, and an ABCD1 p.R163G substitution. We also review a total of 34 cases of adult-onset cerebello-brainstem dominant form of X-ALD. Although rare, X-ALD should be considered in the differential diagnosis of MSA.

Leukoencephalopathy in adults: is it adrenoleukodystrophy? A case report and molecular analysis

Adult onset cerebral X-ALD (AOCALD) is a rare disease, but should be considered an important differential diagnosis in adults presenting with leukencephalopathy. We here report the case of a 40-year-old man with a history of progressive cognitive decline who presented with a first-time seizure. Initial workup included magnetic resonance imaging (MRI) of the brain which showed extensive frontotemporal leukoencephalopathy. A subsequent brain biopsy showed demyelination and perivascular macrophages. Further workup included serum very long chain fatty acid concentration (VLCFA), which was found to be elevated. An MRI of the total spine showed diffuse atrophy, but no intrinsic cord signal changes, and the diagnosis of AOCALD was established. Genomic sequencing revealed a nonsense mutation in exon 8 (2188G-->A, W601X), to our knowledge not reported in context with AOCALD. A family pedigree was obtained, and other family members at risk were identified and underwent genetic counseling. In conclusion, AOCALD is an important differential diagnosis in adults presenting with cognitive decline. While treatment for affected patients is often supportive only, molecular diagnosis serves as a basis for genetic counseling, identification of relatives at risk and timely referral to a treatment program.

Positron emission tomography in juvenile Alexander disease

A 13-year-old boy with cervical kyphosis was diagnosed as having juvenile Alexander disease because of the typical MRI findings, abnormally elevated alphaB-crystallin and heat shock protein 27 in the cerebrospinal fluid. Positron emission tomography with 18F-fluorodeoxyglucose demonstrated hypometabolism in the frontal white matter corresponding to the areas with leukodystrophy. However, the overlying gray matter preserved normal glucose metabolism.