X-linked adrenoleukodystrophy with olivopontocerebellar atrophy

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.

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.

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

Therapy of X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD; OMIM #300100) is caused by defects of the ABCD1 gene on chromosome Xq28, resulting in an impairment of peroxisomal beta-oxidation and the accumulation of saturated very long chain fatty acids (VLCFAs). Primary manifestations occur in the CNS, the adrenal cortex and the testes' Leydig cells. The clinical presentation shows a marked variability which is not explained by the different X-ALD genotypes. Phenotypes range from rapidly progressive cerebral disease with childhood (childhood cerebral ALD [CCALD]) or adulthood (adult cerebral ALD [ACALD]) onset leading to death within a few years, over adult-onset adrenomyeloneuropathy (AMN) with or without focal CNS demyelination, AMN converting into a rapidly progressive, cerebral demyelinating phenotype resembling CCALD, to slow disease progression over decades, or adrenal insufficiency only. Approximately 50% of female heterozygotes develop moderate spastic paresis resembling the AMN phenotype. This review focuses on current experiences with different therapeutic approaches. Lorenzo's oil did not prove to be effective in cerebral inflammatory disease variants, but asymptomatic patients, and speculatively AMN variants without cerebral involvement, as well as female carriers may benefit from early intake of oleic and erucic acids in addition to VLCFA restriction. Hormone-replacement therapy is necessary in all patients with adrenal insufficiency. Hematopoietic stem cell transplantation has been reported to be effective in presymptomatic or early symptomatic CCALD, and may well also be a final therapeutic option in early ACALD patients. Early detection of mutation carriers and timely initiation of therapy is important for the effectiveness of all therapeutic efforts. Gene therapy of endogenous hematopoietic stem cells, pharmacological upregulation of other genes encoding proteins involved in peroxisomal beta-oxidation, reduction of oxidative stress, and possibly lovastatin are candidates for future X-ALD therapies.

Neurological and psychiatric aspects of some endocrine diseases. The role of neurosteroids and neuroactive steroids

A neuroaktív szteroid bármely szervben képződik, módosítani képes a neurális aktivitást különböző membránreceptorok modulálása útján. A neuroszteroid de novo a neuronban és gliában szintetizálódik, a központi idegrendszerben megtalálhatók a szteroidképző enzimek. A citoplazmában klasszikus, genomikus úton szabályzó, hosszú idejű hatásokat kiváltó szteroidhormon-receptorok vannak, a membránban rövid időtartamú, nem klasszikus szteroidreceptorok. Lényeges szerepet játszanak a szteroidreceptorokkal interferáló vagy az aktivitásukat fokozó korepresszorok és koaktivátorok. A kortikoszteroidok a stresszben betöltött funkciójukon túl bizonyított szerepet játszanak a félelemben, szorongásban és memóriafunkciókban, így Cushing-szindrómában gyakran fordul elő hangulatzavar, reverzíbilis cerebrális atrófia a kognitív funkciók átmeneti csökkenésével, ritkábban delírium vagy pszichózis. A periféria részéről közismert a szteroid-myopathia. Az Addison-kórra izomgyengeség, energiacsökkenés, a mentális funkciók és az életminőség csökkenése jellemző. Az ösztrogén és progeszteron saját receptorral rendelkezik, az allopregnanolon a GABA-receptorokon keresztül fejti ki hatását. Alapvető szerepük van az agy fejlődésének, az idegkörök és dendritek architektúrájának, az axonkapcsolatok sűrűségének és a sejtszámnak az alakulásában. Befolyásolják a maturációt, neuroprotekciót, görcskészséget, a kognitív funkciókat, hangulatot, szorongást, fájdalmat és a perifériás idegek restitúcióját. Az androgéneknek is van kapcsolatuk a kognitív funkciókkal, fájdalommal, szorongással, hangulatzavarokkal, valamint az agresszivitással is.