The ovarioleukodystrophy

Ovarioleukodystrophy Due to EIF2B Genes: Systematic Review and Case Report

Leukodystrophies comprise a spectrum of genetic disorders affecting white matter (WM) formation in the central nervous system (CNS), of which vanishing white matter disease (VWMD) is one. VWMD presents with progressive neurological deterioration and a variety of manifestations. Ovarioleukodystrophy, a subtype of VWMD, exhibits a distinctive clinical profile encompassing both CNS WM alterations and ovarian dysfunction. Variants in genes of the eukaryotic translation initiation factor 2B (EIF2B) complex affect the full form and are implicated in VWMD, including ovarioleukodystrophy. This work aimed to systematically review all published cases of ovarioleukodystrophy associated with variants in the EIF2B1-5 gene complex based on the first case identified in a Mexican population. We performed a systematic review according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines of published cases of ovarioleukodystrophy associated with the EIF2B gene complex, including a newly identified case from Mexico. We identified 207 publications using PUBMED, SCOPUS, and PMC databases. One hundred fifty-one publications were eliminated due to duplicates, titles, abstracts, or other reasons, while 56 publications were revised, of which 29 were eliminated because they dealt with other genes or non-human research, and 27 reports were assessed for eligibility. Finally, 14 reports describing ovarian involvement, neuroimaging, and molecular variants were included. Our review identified 20 cases worldwide, with a median age of onset of 19 years. Clinical features included WM involvement, ovarian abnormalities, gait disturbances, epilepsy, cognitive and language impairment, and other neurological manifestations. Neuroimaging showed characteristic WM changes, highlighting the importance of MRI in diagnosis. Missense variants predominated among the identified genetic mutations, especially in the EIF2B4 and EIF2B5 genes. Ovarioleukodystrophy is an ultra-rare disorder with a wide range of clinical manifestations and ovarian changes. Gynecological evaluation is crucial in suspected cases of ovarioleukodystrophy, as ovarian manifestations may precede neurological symptoms. The role of MRI is crucial in the diagnostic approach to this entity. Continued collaborative efforts are essential to elucidate genotype-phenotype correlations, improve clinical management, and promote therapeutic advances for this rare disorder.

Vanishing white matter disease: imaging, clinical and molecular correlation in Brazilian families

PURPOSE

To characterize Vanishing White Matter Disease (VWM) cases from a Brazilian University Tertiary hospital, focusing on brain magnetic resonance image (MRI) aspects, clinical and molecular data.

METHODS

Medical records and brain MRI of 13 genetically confirmed VWM patients were reviewed. Epidemiological data such as age at symptom onset, gender and main symptoms were analyzed, along with genetic mutations and MRI characteristics, such as the distribution of white matter lesions and atrophy.

RESULTS

The majority of patients were female, with the age of symptom onset ranging from 1 year and 6 months to 40 years. All mutations were identified in the EIF2B5 gene, the most prevalent being c.338G > A (p.Arg113His), and a novel mutation related to the disease was discovered, c.1051G > A (p.Gly351Ser). Trauma or infection were significant triggers. The most frequent symptoms were ataxia and limb spasticity. All MRI scans displayed deep white matter involvement, cystic degeneration, with U-fibers relatively spared and a predilection for the frontoparietal region. Lesions in the corpus callosum and posterior fossa were present in all patients. Follow-up exams revealed the evolution of white matter lesions and cerebral atrophy, which correlated with clinical deterioration.

CONCLUSIONS

VWM affects various age groups, with a significant clinical and genetic variability. A novel mutation associated with the disease is highlighted. MRI reveals a typical pattern of white matter involvement, characterized by diffuse lesions in the periventricular and deep regions, with subsequent extension to the subcortical areas, accompanied by cystic degeneration, and plays a crucial role in diagnosis and follow-up.

Vanishing White Matter Disease Presenting as Dementia and Infertility: A Case Report

Objectives

Vanishing white matter (VWM), an inherited leukoencephalopathy affecting the brain and the spinal cord, is most often a childhood-onset progressive disorder, generally presenting with ataxia. The adult-onset VWM is relatively rare with slowly progressive cognitive dysfunction dominating the clinical presentation. We report a case of adult-onset VWM from the Indian subcontinent.

Methods

Exome sequencing.

Results

A 58-year-old woman with young-onset diabetes and hypertension presented with gradually progressive cognitive decline beginning at age 40 years. She had early and predominant executive dysfunction and emotional lability and late involvement of memory and navigation. In addition to cognitive dysfunction, the patient experienced bladder and bowel incontinence along with a spastic gait. She also had primary infertility and menopause at age 40 years. Two of the patient's sisters had primary infertility; one of them had urine and stool incontinence along with gait disturbance. An MRI examination of the brain showed diffuse, symmetrical T2/fluid-attenuated inversion recovery white matter hyperintensities. On genetic testing, the patient was found to be homozygous for c.687T>G variation in the EIF2B3 gene.

Discussion

Adult-onset VWM is rare. Infertility in an adult patient with progressive cognitive decline should raise a suspicion of VWM.

A (dis)integrated stress response: Genetic diseases of eIF2α regulators

The integrated stress response (ISR) is a conserved mechanism by which eukaryotic cells remodel gene expression to adapt to intrinsic and extrinsic stressors rapidly and reversibly. The ISR is initiated when stress-activated protein kinases phosphorylate the major translation initiation factor eukaryotic translation initiation factor 2ɑ (eIF2ɑ), which globally suppresses translation initiation activity and permits the selective translation of stress-induced genes including important transcription factors such as activating transcription factor 4 (ATF4). Translationally repressed messenger RNAs (mRNAs) and noncoding RNAs assemble into cytoplasmic RNA-protein granules and polyadenylated RNAs are concomitantly stabilized. Thus, regulated changes in mRNA translation, stability, and localization to RNA-protein granules contribute to the reprogramming of gene expression that defines the ISR. We discuss fundamental mechanisms of RNA regulation during the ISR and provide an overview of a growing class of genetic disorders associated with mutant alleles of key translation factors in the ISR pathway. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA in Disease and Development > RNA in Disease Translation > Translation Regulation RNA in Disease and Development > RNA in Development.

Optimizing Fertility in Primary Ovarian Insufficiency: Case Report and Literature Review

Primary ovarian insufficiency (POI) is a clinical spectrum of ovarian dysfunction. Overt POI presents with oligo/amenorrhea and hypergonadotropic hypogonadism before age 40 years. Overt POI involves chronic health problems to include increased morbidity and mortality related to estradiol deficiency and the associated osteoporosis and cardiovascular disease as well as psychological and psychiatric disorders related to the loss of reproductive hormones and infertility. Presently, with standard clinical testing, a mechanism for Overt POI can only be identified in about 10% of cases. Now discovery of new mechanisms permits an etiology to be identified in a research setting in 25-30% of overt cases. The most common genetic cause of Overt POI is premutation in FMR1. The associated infertility is life altering. Oocyte donation is effective, although many women prefer to conceive with their own ova. Surprisingly, the majority who have Overt POI still have detectable ovarian follicles (70%). The major mechanism of follicle dysfunction in Overt POI has been histologically defined by a prospective NIH study: inappropriate follicle luteinization due to the tonically elevated serum LH levels. A trial of physiologic hormone replacement therapy, clinically proven to suppress the elevated LH levels in these women, may improve follicle function and increase the chance of ovulation. Here, we report the case of a woman with Overt POI diagnosed at age 35 years. To attempt pregnancy, she elected a trial of intrauterine insemination (IUI) in conjunction with follicle monitoring and physiologic hormone replacement therapy. She conceived on the eighth cycle of treatment and delivered a healthy baby. Our report calls for a concerted effort to define the best methods by which to optimize fertility for women who have POI.

Vanishing white matter: a leukodystrophy due to astrocytic dysfunction

VWM is one of the most prevalent leukodystrophies with unique clinical, pathological and molecular features. It mostly affects children, but may develop at all ages, from birth to senescence. It is dominated by cerebellar ataxia and susceptible to stresses that act as factors provoking disease onset or episodes of rapid neurological deterioration possibly leading to death. VWM is caused by mutations in any of the genes encoding the five subunits of the eukaryotic translation initiation factor 2B (eIF2B). Although eIF2B is ubiquitously expressed, VWM primarily manifests as a leukodystrophy with increasing white matter rarefaction and cystic degeneration, meager astrogliosis with no glial scarring and dysmorphic immature astrocytes and increased numbers of oligodendrocyte progenitor cells that are restrained from maturing into myelin-forming cells. Recent findings point to a central role for astrocytes in driving the brain pathology, with secondary effects on both oligodendroglia and axons. In this, VWM belongs to the growing group of astrocytopathies, in which loss of essential astrocytic functions and gain of detrimental functions drive degeneration of the white matter. Additional disease mechanisms include activation of the unfolded protein response with constitutive predisposition to cellular stress, failure of astrocyte-microglia crosstalk and possibly secondary effects on the oxidative phosphorylation. VWM involves a translation initiation factor. The group of leukodystrophies due to defects in mRNA translation is also growing, suggesting that this may be a common disease mechanism. The combination of all these features makes VWM an intriguing natural model to understand the biology and pathology of the white matter.

New Insights in Vanishing White Matter Disease: Isolated Bilateral Optic Neuropathy in Adult Onset Disease

BACKGROUND

Vanishing white matter disease (VWMD) is a rare disease affecting cerebral white matter. The adult form is even rarer and manifests with motor symptoms, behavioral problems, and dementia. There is no treatment and progression is inevitable. We describe a case with atypical manifestations and an unusual course.

METHODS

Description of a 42-year-old man with VWMD complaining of progressive visual loss in the right eye.

RESULTS

The patient's visual acuity was 20/60, right eye, and 20/25, left eye, with pale optic nerves bilaterally. MRI showed atrophy of the corpus callosum, diffuse rarefaction of cerebral white matter including the anterior and posterior visual pathways.

CONCLUSION

Our patient had no further symptoms besides loss of visual acuity, which is rare in patients with VWMD of the same age and genetic mutation.

Genetics of primary ovarian insufficiency

Primary ovarian insufficiency (POI) is characterized by a loss of ovarian function before the age of 40 and account for one major cause of female infertility. POI relevance is continuously growing because of the increasing number of women desiring conception beyond 30 years of age, when POI prevalence is >1%. POI is highly heterogeneous and can present with ovarian dysgenesis and primary amenorrhea, or with secondary amenorrhea, and it can be associated with other congenital or acquired abnormalities. In most cases POI remains classified as idiopathic. However, the age of menopause is an inheritable trait and POI has a strong genetic component. This is confirmed by the existence of several candidate genes, experimental and natural models. The variable expressivity of POI defect may indicate that, this disease may frequently be considered as a multifactorial or oligogenic defect. The most common genetic contributors to POI are the X chromosome-linked defects. Here, we review the principal X-linked and autosomal genes involved in syndromic and non-syndromic forms of POI with the expectation that this list will soon be upgraded, thus allowing the possibility to predict the risk of an early age at menopause in families with POI.

The first Japanese case of leukodystrophy with ovarian failure arising from novel compound heterozygous AARS2 mutations

Even now, only a portion of leukodystrophy patients are correctly diagnosed, though various causative genes have been identified. In the present report, we describe a case of adult-onset leukodystrophy in a woman with ovarian failure. By whole-exome sequencing, a compound heterozygous mutation consisting of NM_020745.3 (AARS2_v001):c.1145C>A and NM_020745.3 (AARS2_v001):c.2255+1G>A was identified. Neither of the mutations has been previously reported, and this is the first report of alanyl-transfer RNA synthetase 2 mutation in Asia. We anticipate that further studies of the molecular basis of leukodystrophy will provide insight into its pathogenesis and hopefully lead to sophisticated diagnostic and treatment strategies.

Genetics of primary ovarian insufficiency: new developments and opportunities

BACKGROUND

Primary ovarian insufficiency (POI) is characterized by marked heterogeneity, but with a significant genetic contribution. Identifying exact causative genes has been challenging, with many discoveries not replicated. It is timely to take stock of the field, outlining the progress made, framing the controversies and anticipating future directions in elucidating the genetics of POI.

METHODS

A search for original articles published up to May 2015 was performed using PubMed and Google Scholar, identifying studies on the genetic etiology of POI. Studies were included if chromosomal analysis, candidate gene screening and a genome-wide study were conducted. Articles identified were restricted to English language full-text papers.

RESULTS

Chromosomal abnormalities have long been recognized as a frequent cause of POI, with a currently estimated prevalence of 10-13%. Using the traditional karyotype methodology, monosomy X, mosaicism, X chromosome deletions and rearrangements, X-autosome translocations, and isochromosomes have been detected. Based on candidate gene studies, single gene perturbations unequivocally having a deleterious effect in at least one population include Bone morphogenetic protein 15 (BMP15), Progesterone receptor membrane component 1 (PGRMC1), and Fragile X mental retardation 1 (FMR1) premutation on the X chromosome; Growth differentiation factor 9 (GDF9), Folliculogenesis specific bHLH transcription factor (FIGLA), Newborn ovary homeobox gene (NOBOX), Nuclear receptor subfamily 5, group A, member 1 (NR5A1) and Nanos homolog 3 (NANOS3) seem likely as well, but mostly being found in no more than 1-2% of a single population studied. Whole genome approaches have utilized genome-wide association studies (GWAS) to reveal loci not predicted on the basis of a candidate gene, but it remains difficult to locate causative genes and susceptible loci were not always replicated. Cytogenomic methods (array CGH) have identified other regions of interest but studies have not shown consistent results, the resolution of arrays has varied and replication is uncommon. Whole-exome sequencing in non-syndromic POI kindreds has only recently begun, revealing mutations in the Stromal antigen 3 (STAG3), Synaptonemal complex central element 1 (SYCE1), minichromosome maintenance complex component 8 and 9 (MCM8, MCM9) and ATP-dependent DNA helicase homolog (HFM1) genes. Given the slow progress in candidate-gene analysis and relatively small sample sizes available for GWAS, family-based whole exome and whole genome sequencing appear to be the most promising approaches for detecting potential genes responsible for POI.

CONCLUSION

Taken together, the cytogenetic, cytogenomic (array CGH) and exome sequencing approaches have revealed a genetic causation in ∼20-25% of POI cases. Uncovering the remainder of the causative genes will be facilitated not only by whole genome approaches involving larger cohorts in multiple populations but also incorporating environmental exposures and exploring signaling pathways in intragenic and intergenic regions that point to perturbations in regulatory genes and networks.

Adult-onset vanishing white matter disease due to a novel EIF2B3 mutation

OBJECTIVE

To report a novel mutation in the gene EIF2B3 responsible for a late-onset form of vanishing white matter disease.

DESIGN

Case report.

SETTING

University teaching hospital.

PATIENT

A 29-year-old pregnant woman with a history of premature ovarian failure and hemiplegic migraines presented with a 10-week history of progressive confusion and headaches. Magnetic resonance imaging of the brain revealed a diffuse leukoencephalopathy.

RESULTS

Sequencing of the exons and intron boundaries of EIF2B3 uncovered 2 missense mutations: c.260C>T(p.Ala87Val) and c.272G>A(p.Arg91His). To our knowledge,the latter missense mutation has never been previously reported.

CONCLUSION

This is the second report of adult-onset vanishing white matter disease due to mutations in EIF2B3 and the first report of the c.272G>A (p.Arg91His) missense mutation.

Ovarioleukodystrophy: report of a case with the c.338G>A (p.Arg113His) mutation on exon 3 and the c.896G>A (p.Arg299His) mutation on exon 7 of the EIF2B5 gene

The authors present a 28-year-old lady with progressive neurological deterioration beginning in childhood. She had clinical, radiological and genetic features of ovarioleukodystrophy. This is part of the spectrum of vanishing white matter disease and the first such case reported in the UK. The authors also discuss the literature on the disease.

Leukoencephalopathy with vanishing white matter: a review

Vanishing white matter (VWM) is one of the most prevalent inherited childhood leukoencephalopathies, but this may affect people of all ages, including neonates and adults. It is a progressive disorder clinically dominated by cerebellar ataxia and in which minor stress conditions, such as fever or mild trauma, provoke major episodes of neurologic deterioration. Typical pathological findings include increasing white matter rarefaction and cystic degeneration, oligodendrocytosis with highly characteristic foamy oligodendrocytes, meager astrogliosis with dysmorphic astrocytes, and loss of oligodendrocytes by apoptosis. Vanishing white matter is caused by mutations in any of the genes encoding the 5 subunits of the eukaryotic translation initiation factor 2B (eIF2B), EIF2B1 through EIF2B5. eIF2B is a ubiquitously expressed protein complex that plays a crucial role in regulating the rate of protein synthesis. Vanishing white matter mutations reduce the activity of eIF2B and impair its function to couple protein synthesis to the cellular demands in basal conditions and during stress. Reduced eIF2B activity leads to sustained improper activation of the unfolded protein response, resulting in concomitant expression of proliferation, prosurvival, and proapoptotic downstream effectors. Consequently, VWM cells are constitutively predisposed and hyperreactive to stress. In view of the fact that VWM genes are housekeeping genes, it is surprising that the disease is primarily a leukoencephalopathy. The pathophysiology of selective glial vulnerability in VWM remains poorly understood.

Leukodystrophies with late disease onset: an update

PURPOSE OF REVIEW

Knowledge of the metabolic and genetic basis of known and previously unknown leukodystrophies is constantly increasing, opening new treatment options such as enzyme replacement or cell-based therapies. This brief review highlights some recent work, particularly emphasizing results from studies in adulthood leukodystrophies.

RECENT FINDINGS

Evidence from recent studies suggests increasing importance of metabolic dysfunctions, for example, in peroxisomal lipid metabolism or energy homeostasis, influencing axonal integrity and oligodendrocyte function and leading to white matter demyelination. In addition, diagnostic and therapeutic progress in metachromatic leukodystrophy, X-linked adrenoleukodystrophy, Krabbe diseases and other rare leukodystrophies with late onset are summarized.

SUMMARY

Better understanding of leukodystrophies in neurological routine practice is of crucial importance for differentiating between other white matter diseases such as toxic, inflammatory or vascular leukoencephalopathies. Many leukodystrophies are particularly important to recognize because specific treatments already exist or are currently under investigation. The article also provides an overview of currently known leukodystrophies in adulthood.

Leukoencephalopathies and leukodystrophies

The leukoencephalopathies encompass a heterogeneous group of disorders that involve the brain white matter. The cause may be acquired or inherited; in the latter case, mutations have been found in genes that encode protein components of the myelin membrane or enzymes implicated in the turnover of myelin. In patients with cognitive dysfunction and white matter lesions evident on MRI, analysis of the type, pattern, and distribution of lesions can enable a presumptive diagnosis, which can be confirmed by biochemical and/or molecular testing. The presence or absence of peripheral neuropathy and/or autonomic dysfunction can be a helpful clue in differentiating individual diagnoses. Often, patients may be suspected of having and being initially treated inappropriately for a case of primary or secondary progressive multiple sclerosis. In a significant number of patients, the diagnosis may not be made, even after an extensive search. Establishing the cause enables counseling regarding prognosis, family planning, monitoring for disease-related complications, and introducing therapy, when available.