X-linked adrenoleukodystrophy: spinocerebellar variant

A female adult-onset X-ALD patient with pure cerebellar symptoms:a case report

X-linked adrenoleukodystrophy (X-ALD) caused by ATP-binding cassette subfamily D member 1 (ABCD1) gene defects is the most common inherited peroxisomal disorder.The female cerebello-brainstem dominant type in which cerebellum and brainstem are mainly involved is very rare. We report a 40-year-old female who was diagnosed as the rare disorder with magnetic resonance imaging (MRI) and genetic analysis mainly. Her initial symptoms were progressive slurred speech and writing disturbance. Her brain MRI showed obvious atrophy of brainstem and cerebellum. She did not have adrenal insufficiency. Genetic analysis showed a heterozygous missense mutation in exon 4 of the coding region of ABCD1 (c.1252C > T, p.Arg418Trp).This is the first report of this particular mutation being associated with the cerebello-brainstem dominant phenotype of X-ALD, as well as the first description of this X-ALD variant in a (heterozygous) female patient.X-ALD should be considered in young and middle-aged patients with slow-progressing ataxia and dysarthria.

Cerebello-brainstem dominant form of X-linked adrenoleukodystrophy with intrafamilial phenotypic variability

Objectives

This study aimed to describe the clinical and radiological characteristics of a cerebello-brainstem dominant form of X-linked adrenoleukodystrophy (X-ALD).

Methods

Three affected members from a family with cerebellar ataxia received full neurological, laboratory and radiological examinations. Genetic diagnoses were confirmed using whole-exome sequencing and protein structural modeling.

Results

All affected members presented with slurred speech, ataxia, and spasticity, but showed obvious differences in phenotypic severity and radiological findings. The levels of very long-chain fatty acids (VLCFA) were elevated in each member, while only one had adrenal dysfunction. Genetic analysis identified a hemizygous missense mutation (c.887A>G, p.Tyr296Cys) of the ATP-binding cassette subfamily D member 1 gene (ABCD1) in all affected members, which is likely to destabilize the overall structure of the ABCD1 protein.

Conclusions

We report a cerebello-dominant form of X-ALD caused by a missense variant in ABCD1. This report highlights intrafamilial phenotypic variability in X-ALD.

Leukoencephalopathy With Predominant Infratentorial Involvement Caused by a Novel ABCD1 Mutation: Does the Spinocerebellar Variant of Adrenoleukodystrophy Exist?

INTRODUCTION

X-linked adrenoleukodystrophy (X-ALD) encompasses several clinical and neuroimaging phenotypes, including cerebral X-ALD, the most common phenotype in children, and adrenomyeloneuropathy, the most common phenotype in adults. A spinocerebellar variant of X-ALD has been described in individuals from the Far East, but the criteria for its diagnosis are unclear.

CASE REPORT

A 35-year-old man from Albania was assessed because of a familial, slowly progressive spastic-ataxic gait associated with neurogenic bladder, sexual dysfunctions, and manic-like behavior. There was no definite clinical feature that suggested cerebellar involvement (eg, cerebellar limb ataxia, nystagmus, and dysarthria). A few months earlier, he had received a diagnosis of Addison disease. Brain magnetic resonance imaging showed a leukoencephalopathy with predominant cerebellum and brainstem involvement, and FDG-PET revealed marked cerebellar hypometabolism. The diagnosis of X-ALD was made because we found an increase of very long chain fatty acids, and a new ABCD1 mutation (c.1627C>T, p.Pro543Ser).

CONCLUSIONS

X-ALD should be included in the differential diagnosis of adult leukoencephalopathies with predominant involvement of infratentorial structures, that is, the cerebellum and brainstem. From a classification perspective, our patient (of white origin), like others (all of Asian origin), should be considered as suffering from a variant of adrenomyeloneuropathy rather than from spinocerebellar X-ALD. Actually, the term "spinocerebellar" or similar ones, such as "cerebello-brainstem dominant form," should be limited to those exceptional cases, in which both the clinical and neuroimaging findings point exclusively (or at least predominantly) to the involvement of infratentorial structures.

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.

Autosomal Dominant Spinocerebellar Ataxias: An Asian Perspective

Autosomal dominant cerebellar ataxias, frequently referred to as spinocerebellar ataxias (SCAs) have been under intense scientific research limelight since expansions of coded CAG trinucleotide repeats were demonstrated to cause several dominantly inherited SCAs. The number of new SCA loci has expanded dramatically in recent years. At least ten genes have been identified for SCAs 1, 2, 3, 6, 7, 8, 10, 12, 17, dentatorubral-pallidoluysian atrophy (DRPLA), and six loci responsible for SCAs 4, 5, 11,13, 14, and 16 have been mapped. Genetic testing is essential for diagnosis due to the overlapping and varied phenotypic features of the different SCAs. While there is no effective treatment available, genetic counseling is important for addressing the many ethical, social, legal, and psychological issues facing SCA patients. Researchers have recently provided valuable information on the pathogenesis of the disease and hopefully a cure will be available in the near future.

Isolated cerebellar variant of adrenoleukodystrophy with a de novo adenosine triphosphate-binding cassette D1 (ABCD1) gene mutation

X-linked adrenoleukodystrophy (X-ALD) shows a wide range of phenotypic expression, but clinical presentation as an isolated lesion of the cerebellar white matter and dentate nuclei has not been reported. We report an unusual presentation of X-ALD only with an isolated lesion of the cerebellar white matter and dentate nuclei. The proband, a 37-year-old man presented with bladder incontinence, slurred speech, dysmetria in all limbs, difficulties in balancing, and gait ataxia. Brain magnetic resonance imaging showed an isolated signal change of white matter around the dentate nucleus in cerebellum. With high level of very long chain fatty acid, gene study showed a de novo mutation in exon 1 at nucleotide position c.277_296dup20 (p.Ala100Cysfs*10) of the adenosine triphosphate-binding cassette D1 gene. It is advised to consider X-ALD as a differential diagnosis in patients with isolated cerebellar degeneration symptoms.

Clinical and genetic aspects in twelve Korean patients with adrenomyeloneuropathy

PURPOSE

This study was designed to investigate the characteristics of Korean adrenomyeloneuropathy (AMN) patients.

MATERIALS AND METHODS

We retrospectively selected 12 Korean AMN patients diagnosed by clinical analysis and increased plasma content of very long chain fatty acids.

RESULTS

All 12 patients were men. Patient ages at symptom onset ranged from 18 to 55 years. Family history was positive in two patients. The phenotype distributions consisted of AMN without cerebral involvement in seven patients, AMN with cerebral involvement in two patients, and the spinocerebellar phenotype in three patients. Nerve conduction studies revealed abnormalities in four patients and visual evoked tests revealed abnormalities in three patients. Somatosensory evoked potential tests revealed central conduction defects in all of the tested patients. Spinal MRI showed diffuse cord atrophy or subtle signal changes in all 12 patients. Brain MRI findings were abnormal in six of the nine tested patients. These brain abnormalities reflected the clinical phenotypes. Mutational analysis identified nine different ABCD1 mutations in 10 of 11 tested patients. Among them, nine have been previously reported and shown to be associated with various phenotypes; one was a novel mutation.

CONCLUSION

In conclusion, the present study is the first to report on the clinical and mutational spectrum of Korean AMN patients, and confirms various clinical presentations and the usefulness of brain MRI scan.

Spinocerebellar variant of adrenoleukodystrophy with a novel ABCD1 gene mutation

X-linked adrenoleukodystrophy (X-ALD) shows a wide range of phenotypic expression, and clinical presentation as adult-onset spinocerebellar ataxia has been rarely reported. Here, we report a Taiwanese family with X-ALD. The proband, a 37-year-old man presented with dysarthria, cerebellar ataxia and mild spastic paraparesis, and had atrophy of cerebellum and upper cervical cord on MRI. One of his nephews, a 9-year-old boy had a classic childhood cerebral ALD phenotype. This family harbors a novel deletion of 1 base pair in exon 8 at nucleotide position 2245 (2245delA) in the ABCD1 gene. This is the first report of the 2245delA mutation presenting with a spinocerebellar variant of X-ALD.

A case of adrenoleukodystrophy presenting as progressive cerebellar dysfunction

X-linked adrenoleukodystrophy (X-ALD) is a hereditary neurological disorder affecting the nervous system and adrenal cortex. The phenotype of X-ALD ranges from the rapidly progressive cerebral form to milder adrenomyeloneuropathy. However, cerebellar manifestations are rare. We report a case of adrenoleukodystrophy presenting as progressive cerebellar dysfunction resembling olivopontocerebellar degeneration, with a review of the literature

Manifestation of neurofibromatosis 1 in a patient with X-linked adrenoleukodystrophy

A patient with X-linked adrenoleukodystrophy exhibited a phenotype of neurofibromatosis 1. He had large and multiple café-au-lait spots, and had elevated serum levels of very long chain fatty acids. The patient's mother and elder sister also had X-linked adrenoleukodystrophy. This case represents novel manifestations of neurofibromatosis 1 in a patient with X-linked adrenoleukodystrophy.

X-linked adrenoleukodystrophy with olivopontocerebellar atrophy

X-linked adrenoleukodystrophy (X-ALD) is a rare neurological disorder characterized by adrenal, gonadal and nervous system dysfunction. Patients usually develop spinal cord degeneration with involvement of the cerebral white matter. While a spinocerebellar variant has been described, the selective involvement of cerebellar white matter is very rare. We report the case of a patient affected by X-ALD whose clinical and magnetic resonance imaging (MRI) results resembled olivopontocerebellar atrophy. He was a 29-year-old mentally retarded man, who began to complain of slowly progressive gait ataxia after an 8-year history of Addison's disease. Serial MRI revealed marked cerebellar atrophy involving the inferior cerebellar vermis and brainstem, but sparing the supratentorial white matter. The diagnosis of X-ALD was confirmed by elevated levels of very long-chain fatty acids in the serum. After 2 years follow-up, the patient developed spastic paraparesis. The patient represents an unusual clinical presentation of X-ALD, as further confirmed by the MRI results. Consequently, cerebellar symptoms should be considered as a clinical presentation of X-ALD. Early recognition of this rare disorder would be useful for genetic counselling and therapy.