Molecular, clinical and peripheral neuropathy study of Tunisian patients with ataxia with vitamin E deficiency

Ataxia in Africa: current efforts and recommendations

Ataxia which is a disorder of the nervous system with the primary symptom being unsteady mobility is becoming more prevalent especially within the African continent. Nonetheless, it is suggested that there may be more cases of ataxia that are still undiagnosed roughly and this has to do with very few health care facilities offering genetic testing. This disease is most commonly associated with a variety of neurological illnesses, including stroke and brain damage leading to the uncontrollable moving of the limbs. However, in Africa, the primary contributors to the increase in ataxia are infectious diseases and food scarcity caused by drought. In our article, we analyze the different types of ataxia according to their epidemiology and describe how sociological factors aggravate the situation. We detail existing national strategies and programs aimed at solving this problem, particularly increasing funding for the infrastructure necessary for genetic testing, imagining and brain studies. Even with these measures, there remain a number of gaps with regard to epidemiology studies that need painting so as aid in accurating in the diagnosis. Awareness of the problem regarding patient education and active healthcare personnel has to be raised too. We advocate working on various fronts, including nutritional intervention, support groups for the patients, or modifying occupation therapy programs. Such measures are necessary to increase the effectiveness of ataxia treatment and improve the quality of life of patients.

Clinical and biochemical footprints of inherited metabolic diseases: Ia. Movement disorders, updated

Movement disorders are a common manifestation of inherited metabolic diseases (IMDs), categorized into hyperkinetic movement disorders, hypokinetic-rigid syndromes, ataxia, and spasticity. We reviewed and updated the list of known metabolic disorders associated with movement disorders, identifying a total of 559 IMDs. We outlined the more common and treatable causes, sorted by the dominant movement disorder phenomenology, and provided a practical clinical approach for suspected IMDs presenting with movement disorders. This work represents an updated catalog in a series of articles aimed at creating and maintaining a comprehensive list of clinical and metabolic differential diagnoses based on system involvement.

A TTPA deletion is associated with retinopathy with vitamin E deficiency in the English Cocker Spaniel dog

Retinopathy with vitamin E deficiency is a familial disease in the English Cocker Spaniel dog breed. Ophthalmic abnormalities observed in retinopathy with vitamin E deficiency-affected English Cocker Spaniel include lipofuscin granule deposition within the tapetal fundus and subsequent retinal degeneration resulting in visual deficits. Affected dogs may also exhibit neurological signs that include ataxia and hindlimb proprioceptive deficits. In all cases, circulating plasma concentrations of α-tocopherol are low. This study sought to investigate the genetic basis of retinopathy with vitamin E deficiency in the English Cocker Spaniel breed. We undertook a genome-wide association study comprising 30 English Cocker Spaniels with normal fundic examinations aged 6 years or older (controls) and 20 diagnosed with retinopathy with vitamin E deficiency (cases) and identified a statistically associated signal on chromosome 29 (Praw = 1.909 × 10-17). Whole genome sequencing of 2 cases identified a 102 bp deletion in exon 1 of the alpha-tocopherol transfer protein gene (TTPA), truncating the protein by 34 amino acids. The c.23_124del variant segregated with retinopathy with vitamin E deficiency in a total of 30 cases and 43 controls. Variants in TTPA are causal for ataxia with vitamin E deficiency in humans which is a phenotypically similar disease to retinopathy with vitamin E deficiency. The identification of the canine variant is extremely significant as the availability of a DNA test will allow for identification of presymptomatic dogs and early therapeutic intervention which may prevent development of retinopathy and improve neurological signs. Breeders can also use the DNA test to efficiently eradicate the disease from this breed.

Autosomal Recessive Ataxias in Northeast Brazil: A Regional Multicenter Case Series

Hereditary cerebellar ataxias are a diverse group of neurodegenerative disorders characterized by progressive cerebellar dysfunction and possible multisystemic involvement. While significant advancements have been made in understanding autosomal dominant cerebellar ataxias (ADCAs), autosomal recessive cerebellar ataxias (ARCAs) remain less extensively investigated than autosomal dominant ataxias, particularly in regions with high consanguinity. This study aimed to characterize 57 patients with ARCAs in Ceará, northeast Brazil. We analyzed 57 patients diagnosed with ARCAs caused by biallelic variants in ARCA-associated genes. Patients underwent clinical evaluations, including neurological examinations and functional assessments.

RESULTS

Friedreich's ataxia (FRDA) was the most prevalent diagnosis, accounting for 12 cases (21%), followed by Ataxia-Telangiectasia (A-T) with (N = 9; 15.8%) and Niemann-Pick Disease Type C (NPC) (N = 9; 15.8%). Metabolic disorders, including Cerebrotendinous Xanthomatosis (N = 6;10.5%) were also common causes. The cohort demonstrated a broad age distribution, with childhood-onset conditions such as A-T predominantly affecting younger patients. In contrast, adult-onset conditions like FRDA and NPC were more common in those aged 18 years and older.

DISCUSSION

This study highlights the heterogeneity of ARCAs in a region with high consanguinity, reflecting these disorders' diverse genetic and clinical spectrum.

CONCLUSION

The clinical and genetic characterization of ARCAs presented in this case series emphasizes the importance of early diagnosis, genetic confirmation, and targeted management strategies. Our findings highlight the need for continued research and expanded diagnostic programs, particularly in regions with high consanguinity, to improve patient outcomes and advance therapeutic development.

Syndromic retinitis pigmentosa

Retinitis pigmentosa (RP) is a progressive inherited retinal dystrophy, characterized by the degeneration of photoreceptors, presenting as a rod-cone dystrophy. Approximately 20-30% of patients with RP also exhibit extra-ocular manifestations in the context of a syndrome. This manuscript discusses the broad spectrum of syndromes associated with RP, pathogenic mechanisms, clinical manifestations, differential diagnoses, clinical management approaches, and future perspectives. Given the diverse clinical and genetic landscape of syndromic RP, the diagnosis may be challenging. However, an accurate and timely diagnosis is essential for optimal clinical management, prognostication, and potential treatment. Broadly, the syndromes associated with RP can be categorized into ciliopathies, inherited metabolic disorders, mitochondrial disorders, and miscellaneous syndromes. Among the ciliopathies associated with RP, Usher syndrome and Bardet-Biedl syndrome are the most well-known. Less common ciliopathies include Cohen syndrome, Joubert syndrome, cranioectodermal dysplasia, asphyxiating thoracic dystrophy, Mainzer-Saldino syndrome, and RHYNS syndrome. Several inherited metabolic disorders can present with RP, including Zellweger spectrum disorders, adult Refsum disease, α-methylacyl-CoA racemase deficiency, certain mucopolysaccharidoses, ataxia with vitamin E deficiency, abetalipoproteinemia, several neuronal ceroid lipofuscinoses, mevalonic aciduria, PKAN/HARP syndrome, PHARC syndrome, and methylmalonic acidaemia with homocystinuria type cobalamin (cbl) C disease. Due to the mitochondria's essential role in supplying continuous energy to the retina, disruption of mitochondrial function can lead to RP, as seen in Kearns-Sayre syndrome, NARP syndrome, primary coenzyme Q10 deficiency, SSBP1-associated disease, and long chain 3-hydroxyacyl-CoA dehydrogenase deficiency. Lastly, Cockayne syndrome and PERCHING syndrome can present with RP, but they do not fit the abovementioned hierarchy and are thus categorized as miscellaneous. Several first-in-human clinical trials are underway or in preparation for some of these syndromic forms of RP.

Autosomal recessive cerebellar ataxias: a diagnostic classification approach according to ocular features

Autosomal recessive cerebellar ataxias (ARCAs) are a heterogeneous group of neurodegenerative disorders affecting primarily the cerebellum and/or its afferent tracts, often accompanied by damage of other neurological or extra-neurological systems. Due to the overlap of clinical presentation among ARCAs and the variety of hereditary, acquired, and reversible etiologies that can determine cerebellar dysfunction, the differential diagnosis is challenging, but also urgent considering the ongoing development of promising target therapies. The examination of afferent and efferent visual system may provide neurophysiological and structural information related to cerebellar dysfunction and neurodegeneration thus allowing a possible diagnostic classification approach according to ocular features. While optic coherence tomography (OCT) is applied for the parametrization of the optic nerve and macular area, the eye movements analysis relies on a wide range of eye-tracker devices and the application of machine-learning techniques. We discuss the results of clinical and eye-tracking oculomotor examination, the OCT findings and some advancing of computer science in ARCAs thus providing evidence sustaining the identification of robust eye parameters as possible markers of ARCAs.

Metabolic and Toxic Myelopathies

OBJECTIVE

This article reviews the clinical presentation, diagnostic evaluation, and treatment of metabolic and toxic myelopathies resulting from nutritional deficiencies, environmental and dietary toxins, drugs of abuse, systemic medical illnesses, and oncologic treatments.

LATEST DEVELOPMENTS

Increased use of bariatric surgery for obesity has led to higher incidences of deficiencies in nutrients such as vitamin B12 and copper, which can cause subacute combined degeneration. Myelopathies secondary to dietary toxins including konzo and lathyrism are likely to become more prevalent in the setting of climate change leading to drought and flooding. Although modern advances in radiation therapy techniques have reduced the incidence of radiation myelopathy, patients with cancer are living longer due to improved treatments and may require reirradiation that can increase the risk of this condition. Immune checkpoint inhibitors are increasingly used for the treatment of cancer and are associated with a wide variety of immune-mediated neurologic syndromes including myelitis.

ESSENTIAL POINTS

Metabolic and toxic causes should be considered in the diagnosis of myelopathy in patients with particular clinical syndromes, risk factors, and neuroimaging findings. Some of these conditions may be reversible if identified and treated early, requiring careful history, examination, and laboratory and radiologic evaluation for prompt diagnosis.

Atypical retinopathy in ataxia with vitamin E deficiency: report of a sibship

Typical retinitis pigmentosa (RP) may not be the only retinal phenotype encountered in ataxia with vitamin E deficiency (AVED). The following short case series describes a novel form of retinopathy in AVED. We describe two patients with AVED belonging to the same consanguineous sibship. Both presented an unusual retinopathy consisting of scattered, multifocal, nummular, hyperautofluorescent atrophic retinal patches. The retinopathy remained stable under vitamin E supplementation. We hypothesize these changes to be the result of arrested AVED-related RP following early supplementation with α-tocopherol acetate.

Genetic heterogeneity within a consanguineous family involving TTPA and SETX genes

Autosomal recessive cerebellar ataxias (ARCA) constitute a highly heterogeneous group of progressive neurodegenerative disorders that typically occur prior to adulthood. Despite some clinical resemblance between these disorders, different genes are involved. We report in this study four Tunisian patients belonging to the same large consanguineous family, sharing autosomal recessive cerebellar ataxia phenotypes but with clinical, biological, electrophysiological, and radiological differences leading to the diagnosis of two distinct ARCA caused by two distinct gene defects. Two of our patients presented ataxia with the vitamin E deficiency (AVED) phenotype, and the other two presented ataxia with oculo-motor apraxia 2 (AOA2). Genetic testing confirmed the clinical diagnosis by the detection of a frameshift c.744delA pathogenic variant in the TTPA gene, which is the most frequent in Tunisia, and a new variant c.1075dupT in the SETX gene. In Tunisia, data suggest that genetic disorders are common. The combined effects of the founder effect and inbreeding, added to genetic drift, may increase the frequency of detrimental rare disorders. The genetic heterogeneity observed in this family highlights the difficulty of genetic counseling in an inbred population. The examination and genetic testing of all affected patients, not just the index patient, is essential to not miss a treatable ataxia such as AVED, as in the case of this family.

Ataxia in Neurometabolic Disorders

Ataxia is a movement disorder that manifests during the execution of purposeful movements. It results from damage to the structures of the cerebellum and its connections or the posterior cords of the spinal cord. It should be noted that, in addition to occurring as part of many diseases, pediatric ataxia is a common symptom in neurometabolic diseases. To date, there are more than 150 inherited metabolic disorders that can manifest as ataxia in children. Neuroimaging studies (magnetic resonance imaging of the head and spinal cord) are essential in the diagnosis of ataxia, and genetic studies are performed when metabolic diseases are suspected. It is important to remember that most of these disorders are progressive if left untreated. Therefore, it is crucial to include neurometabolic disorders in the differential diagnosis of ataxia, so that an early diagnosis can be made. Initiating prompt treatment influences positive neurodevelopmental outcomes.

Effect of Overexpression of γ-Tocopherol Methyltransferase on α-Tocopherol and Fatty Acid Accumulation and Tolerance to Salt Stress during Seed Germination in Brassica napus L

Rapeseed (Brassica napus L.) is an important oil crop and a major source of tocopherols, also known as vitamin E, in human nutrition. Enhancing the quality and composition of fatty acids (FAs) and tocopherols in seeds has long been a target for rapeseed breeding. The gene γ-Tocopherol methyltransferase (γ-TMT) encodes an enzyme catalysing the conversion of γ-tocopherol to α-tocopherol, which has the highest biological activity. However, the genetic basis of γ-TMT in B. napus seeds remains unclear. In the present study, BnaC02.TMT.a, one paralogue of Brassica napus γ-TMT, was isolated from the B. napus cultivar "Zhongshuang11" by nested PCR, and two homozygous transgenic overexpression lines were further characterised. Our results demonstrated that the overexpression of BnaC02.TMT.a mediated an increase in the α- and total tocopherol content in transgenic B. napus seeds. Interestingly, the FA composition was also altered in the transgenic plants; a reduction in the levels of oleic acid and an increase in the levels of linoleic acid and linolenic acid were observed. Consistently, BnaC02.TMT.a promoted the expression of BnFAD2 and BnFAD3, which are involved in the biosynthesis of polyunsaturated fatty acids during seed development. In addition, BnaC02.TMT.a enhanced the tolerance to salt stress by scavenging reactive oxygen species (ROS) during seed germination in B. napus. Our results suggest that BnaC02.TMT.a could affect the tocopherol content and FA composition and play a positive role in regulating the rapeseed response to salt stress by modulating the ROS scavenging system. This study broadens our understanding of the function of the Bnγ-TMT gene and provides a novel strategy for genetic engineering in rapeseed breeding.

Treatable Ataxias: How to Find the Needle in the Haystack?

Treatable ataxias are a group of ataxic disorders with specific treatments. These disorders include genetic and metabolic disorders, immune-mediated ataxic disorders, and ataxic disorders associated with infectious and parainfectious etiology, vascular causes, toxins and chemicals, and endocrinopathies. This review provides a comprehensive overview of different treatable ataxias. The major metabolic and genetic treatable ataxic disorders include ataxia with vitamin E deficiency, abetalipoproteinemia, cerebrotendinous xanthomatosis, Niemann-Pick disease type C, autosomal recessive cerebellar ataxia due to coenzyme Q10 deficiency, glucose transporter type 1 deficiency, and episodic ataxia type 2. The treatment of these disorders includes the replacement of deficient cofactors and vitamins, dietary modifications, and other specific treatments. Treatable ataxias with immune-mediated etiologies include gluten ataxia, anti-glutamic acid decarboxylase antibody-associated ataxia, steroid-responsive encephalopathy associated with autoimmune thyroiditis, Miller-Fisher syndrome, multiple sclerosis, and paraneoplastic cerebellar degeneration. Although dietary modification with a gluten-free diet is adequate in gluten ataxia, other autoimmune ataxias are managed by short-course steroids, plasma exchange, or immunomodulation. For autoimmune ataxias secondary to malignancy, treatment of tumor can reduce ataxic symptoms. Chronic alcohol consumption, antiepileptics, anticancer drugs, exposure to insecticides, heavy metals, and recreational drugs are potentially avoidable and treatable causes of ataxia. Infective and parainfectious causes of cerebellar ataxias include acute cerebellitis, postinfectious ataxia, Whipple's disease, meningoencephalitis, and progressive multifocal leukoencephalopathy. These disorders are treated with steroids and antibiotics. Recognizing treatable disorders is of paramount importance when dealing with ataxias given that early treatment can prevent permanent neurological sequelae.

Ataxia due to vitamin E deficiency: A case report and updated review

Ataxia with vitamin E deficiency (AVED) is a rare cause of hereditary ataxia in developing countries with unknown prevalence. AVED is an autosomal-recessive disorder, which is characterized by ataxia, areflexia, and proprioceptive and vibratory sensory loss. The disease is characterized clinically by symptoms with often resembling to those of Friedreich ataxia (FRDA). Vitamin E supplementation improves symptoms and prevents the progression of the disease. In this case report, we reviewed the recently updated findings in AVED in regard to the management and present a case of AVED in a 16-year-old boy, who was initially misdiagnosed as FRDA, prior to the genetic test.

Clinical and genetic study of ataxia with vitamin E deficiency: A case report

BACKGROUND

Ataxia with vitamin E deficiency (AVED) is a type of autosomal recessive cerebellar ataxia. Clinical manifestations include progressive cerebellar ataxia and movement disorders. TTPA gene mutations cause the disease.

CASE SUMMARY

We report the case of a 32-year-old woman who presented with progressive cerebellar ataxia, dysarthria, dystonic tremors and a remarkably decreased serum vitamin E concentration. Brain magnetic resonance images showed that her brainstem and cerebellum were within normal limits. Acquired causes of ataxia were excluded. Whole exome sequencing subsequently identified a novel homozygous variant (c.473T>C, p.F158S) of the TPPA gene. Bioinformatic analysis predicted that F185S is harmful to protein function. After supplementing the patient with vitamin E 400 mg three times per day for 2 years, her symptoms remained stable.

CONCLUSION

We identified an AVED patient caused by novel mutation in TTPA gene. Our findings widen the known TTPA gene mutation spectrum.

Role of Vitamin E in Neonatal Neuroprotection: A Comprehensive Narrative Review

Vitamin E (Vit E) is an essential lipophilic antioxidant and anti-inflammatory agent that has potential as a neuroprotectant in newborn infants with brain injury. Vit E has shown promise in many in vitro studies, but success in translation to in vivo animal studies and the clinical setting has been mixed, with concern of adverse effects at high intravenous doses in preterm infants. However, a recent rise in knowledge of the beneficial effects of fat emulsions containing higher levels of Vit E, along with associated improved outcomes in some neonatal co-morbidities, has led many to reconsider Vit E administration as a potential therapeutic modality to improve neurological outcomes in the setting of neonatal brain injury. This narrative review discusses Vit E's structure, mechanism(s) of action, evidence in animal models, and association with health outcomes in neonates, including both dietary and supplemental Vit E and their bioavailability and pharmacokinetics as it relates to the brain. Lastly, long-term neurodevelopmental outcomes along with gaps in current knowledge are critiqued, which to date suggests that additional translational studies in larger animal models and assessment of safety profiles of different routes and doses of administration should be explored prior to large clinical trials. Importantly, a greater understanding of the brain region(s) and cell type(s) affected by Vit E may help to target the use of Vit E as a beneficial neuroprotective agent to specific populations or types of injury seen in newborns.

Discovery of Therapeutics Targeting Oxidative Stress in Autosomal Recessive Cerebellar Ataxia: A Systematic Review

Autosomal recessive cerebellar ataxias (ARCAs) are a heterogeneous group of rare neurodegenerative inherited disorders. The resulting motor incoordination and progressive functional disabilities lead to reduced lifespan. There is currently no cure for ARCAs, likely attributed to the lack of understanding of the multifaceted roles of antioxidant defense and the underlying mechanisms. This systematic review aims to evaluate the extant literature on the current developments of therapeutic strategies that target oxidative stress for the management of ARCAs. We searched PubMed, Web of Science, and Science Direct Scopus for relevant peer-reviewed articles published from 1 January 2016 onwards. A total of 28 preclinical studies fulfilled the eligibility criteria for inclusion in this systematic review. We first evaluated the altered cellular processes, abnormal signaling cascades, and disrupted protein quality control underlying the pathogenesis of ARCA. We then examined the current potential therapeutic strategies for ARCAs, including aromatic, organic and pharmacological compounds, gene therapy, natural products, and nanotechnology, as well as their associated antioxidant pathways and modes of action. We then discussed their potential as antioxidant therapeutics for ARCAs, with the long-term view toward their possible translation to clinical practice. In conclusion, our current understanding is that these antioxidant therapies show promise in improving or halting the progression of ARCAs. Tailoring the therapies to specific disease stages could greatly facilitate the management of ARCAs.

Rice: a potential vehicle for micronutrient fortification

The choices of consumer towards food have been changed. Consumer prefers to eat food which is not only safe but also nutritious. Now a day, they like to eat the food which promote their health and help in minimizing nutrition related health hazards. Rice is a staple food in many countries, but most emerging issue is that rice is deficit in minerals. Rice ranks second among cereals in dietary uses around the world. Rice is deficit in iron (Fe) zinc (Zn) and these are important micronutrients for infants, men and women. Fortification of rice with iron and zinc would help to minimize nutrient deficient disorders among humans. Present study is aimed to introduce nutrients rich rice for consumers and also to encourage food-fortification organizations for diverting their focus on rice fortification. In south Asian countries, micronutrient deficiency especially Fe and Zn deficiency is very common. The rice because of its use as a staple food can be utilized as a carrier medium for transporting micronutrients from plants sources to human beings. Hence, rice fortification with microminerals can prove as a miracle for the virtual eradication of nutrition related diseases in humans.

Clinical and genetic spectrums of 413 North African families with inherited retinal dystrophies and optic neuropathies

Background

Inherited retinal dystrophies (IRD) and optic neuropathies (ION) are the two major causes world-wide of early visual impairment, frequently leading to legal blindness. These two groups of pathologies are highly heterogeneous and require combined clinical and molecular diagnoses to be securely identified. Exact epidemiological studies are lacking in North Africa, and genetic studies of IRD and ION individuals are often limited to case reports or to some families that migrated to the rest of the world. In order to improve the knowledge of their clinical and genetic spectrums in North Africa, we reviewed published data, to illustrate the most prevalent pathologies, genes and mutations encountered in this geographical region, extending from Morocco to Egypt, comprising 200 million inhabitants.

Main body

We compiled data from 413 families with IRD or ION together with their available molecular diagnosis. The proportion of IRD represents 82.8% of index cases, while ION accounted for 17.8%. Non-syndromic IRD were more frequent than syndromic ones, with photoreceptor alterations being the main cause of non-syndromic IRD, represented by retinitis pigmentosa, Leber congenital amaurosis, and cone-rod dystrophies, while ciliopathies constitute the major part of syndromic-IRD, in which the Usher and Bardet Biedl syndromes occupy 41.2% and 31.1%, respectively. We identified 71 ION families, 84.5% with a syndromic presentation, while surprisingly, non-syndromic ION are scarcely reported, with only 11 families with autosomal recessive optic atrophies related to OPA7 and OPA10 variants, or with the mitochondrial related Leber ION. Overall, consanguinity is a major cause of these diseases within North African countries, as 76.1% of IRD and 78.8% of ION investigated families were consanguineous, explaining the high rate of autosomal recessive inheritance pattern compared to the dominant one. In addition, we identified many founder mutations in small endogamous communities.

Short conclusion

As both IRD and ION diseases constitute a real public health burden, their under-diagnosis in North Africa due to the absence of physicians trained to the identification of inherited ophthalmologic presentations, together with the scarcity of tools for the molecular diagnosis represent major political, economic and health challenges for the future, to first establish accurate clinical diagnoses and then treat patients with the emergent therapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02340-7.

Recessive cerebellar and afferent ataxias - clinical challenges and future directions

Cerebellar and afferent ataxias present with a characteristic gait disorder that reflects cerebellar motor dysfunction and sensory loss. These disorders are a diagnostic challenge for clinicians because of the large number of acquired and inherited diseases that cause cerebellar and sensory neuron damage. Among such conditions that are recessively inherited, Friedreich ataxia and RFC1-associated cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) include the characteristic clinical, neuropathological and imaging features of ganglionopathies, a distinctive non-length-dependent type of sensory involvement. In this Review, we discuss the typical and atypical phenotypes of Friedreich ataxia and CANVAS, along with the features of other recessive ataxias that present with a ganglionopathy or polyneuropathy, with an emphasis on recently described clinical features, natural history and genotype-phenotype correlations. We review the main developments in understanding the complex pathology that affects the sensory neurons and cerebellum, which seem to be most vulnerable to disorders that affect mitochondrial function and DNA repair mechanisms. Finally, we discuss disease-modifying therapeutic advances in Friedreich ataxia, highlighting the most promising candidate molecules and lessons learned from previous clinical trials.

MRI CNS Atrophy Pattern and the Etiologies of Progressive Ataxias

MRI shows the three archetypal patterns of CNS volume loss underlying progressive ataxias in vivo, namely spinal atrophy (SA), cortical cerebellar atrophy (CCA) and olivopontocerebellar atrophy (OPCA). The MRI-based CNS atrophy pattern was reviewed in 128 progressive ataxias. A CNS atrophy pattern was identified in 91 conditions: SA in Friedreich’s ataxia, CCA in 5 acquired and 72 (24 dominant, 47 recessive,1 X-linked) inherited ataxias, OPCA in Multi-System Atrophy and 12 (9 dominant, 2 recessive,1 X-linked) inherited ataxias. The MRI-based CNS atrophy pattern may be useful for genetic assessment, identification of shared cellular targets, repurposing therapies or the enlargement of drug indications in progressive ataxias.

Vincristine-Induced Peripheral Neuropathy in Childhood Acute Lymphoblastic Leukemia: Genetic Variation as a Potential Risk Factor

Vincristine (VCR) is the first-line chemotherapeutic medication often co-administered with other drugs to treat childhood acute lymphoblastic leukemia. Dose-dependent neurotoxicity is the main factor restricting VCR’s clinical application. VCR-induced peripheral neuropathy (VIPN) sometimes results in dose reduction or omission, leading to clinical complications or affecting the patient’s quality of life. With regard to the genetic basis of drug responses, preemptive pharmacogenomic testing and simultaneous blood level monitoring could be helpful for the transformation of various findings into individualized therapies. In this review, we discussed the potential associations between genetic variants in genes contributing to the pharmacokinetics/pharmacodynamics of VCR and VIPN incidence and severity in patients with acute lymphoblastic leukemia. Of note, genetic variants in the CEP72 gene have great potential to be translated into clinical practice. Such a genetic biomarker may help clinicians diagnose VIPN earlier. Besides, genetic variants in other genes, such as CYP3A5, ABCB1, ABCC1, ABCC2, TTPA, ACTG1, CAPG, SYNE2, SLC5A7, COCH, and MRPL47, have been reported to be associated with the VIPN, but more evidence is needed to validate the findings in the future. In fact, a variety of complex factors jointly determine the VIPN. In implementing precision medicine, the combination of genetic, environmental, and personal variables, along with therapeutic drug monitoring, will allow for a better understanding of the mechanisms of VIPN, improving the effectiveness of VCR treatment, reducing adverse reactions, and improving patients’ quality of life.

A first description of ataxia with vitamin E deficiency associated with MT-TG gene mutation

Ataxia with isolated vitamin E deficiency (AVED) is a rare autosomal recessive cerebellar ataxia disorder that is caused by a mutation in the alpha-tocopherol transfer protein gene TTPA, leading to a lower level of serum vitamin E. Although it is almost clinically similar to Friedreich's ataxia, its devastating neurological features can be prevented with appropriate treatment. In this study, we present a patient who was initially diagnosed with Friedreich's ataxia, but was later found to have AVED. Frataxin gene screening revealed the absence of GAA expansion in homozygous or heterozygous state. However, TTPAgene sequencing showed the presence of the c.744delA mutation, leading to a premature stop codon (p.E249fx). In addition, the result of mutational analysis of MT-DNA genes revealed the presence of several variants, including the m.10044A>G mutation in MT-TG gene. Here, we report for the first time the coexistence of both mitochondrial and nuclear genes mutations in AVED.

Vitamin E: How much is enough, too much and why!

α-Tocopherol (α-T) is a required dietary nutrient for humans and thus is a vitamin. This narrative review focuses on vitamin E structures, functions, biological determinants and its deficiency symptoms in humans. The mechanisms for the preferential α-T tissue enrichment in the human body include the α-T transfer protein (TTPA) and the preferential metabolism of non-α-T forms. Potential new α-T biomarkers, pharmacokinetic data, and whether there are better approaches to evaluate and set the α-T dietary requirement are discussed. Finally, the possible role of α-T supplements in delay of chronic diseases and the evaluation of vitamin E safety are considered.

Eye motor manifestations in children with neurometabolic disorders

Neurometabolic diseases are complex group of rare neurogenetic disorders, which are difficult to diagnose. Patients may have toxic metabolite accumulation, inadequate energy supply, or neurotransmitter deficiency, resulting in a variety of clinical manifestations and severity with enzyme activity or transporter function defects. Multiple organ involvement is frequently seen, among which neurological symptoms and signs are one of the most encountered problems. Ocular motor problems deserve special attention for it occurs in some inborn error of metabolism. Furthermore, some are early signs or characteristic findings of certain diseases, such as the gaze palsy in Niemann-Pick disease type C and Gaucher disease or oculogyric crisis in neurotransmitter diseases. Early recognition and intervention are important for better prognosis in treatable neurometabolic disorders. In addition, ways to evaluate and describe eye movement problems also help to demonstrate the severity or clinical progression for those diagnosed with certain neurometabolic diseases. However, the complexity of eye movement and ocular motor control renders our clinical observation, recording and even anatomic localization of abnormal eye movements. Clinicians are more likely to detect early signs and unravel problems by gaining awareness of abnormal eye movement. This study amied to approach neurometabolic diseases in children via eye motor manifestations.

Autosomal recessive adult onset ataxia

Autosomal recessive ataxias (ARCA) represent a complex group of diseases ranging from primary ataxias to rare and complex metabolic disorders in which ataxia is a part of the clinical picture. Small number of ARCA manifest exclusively in adulthood, while majority of typical childhood onset ARCA may also start later with atypical clinical presentation. We have systematically searched the literature for ARCA with adult onset, both in the group of primary ataxias including those that are less frequently described in isolated or in a small number of families, and also in the group of complex and metabolic diseases in which ataxia is only part of the clinical picture. We propose an algorithm that could be used when encountering a patient with adult onset sporadic or recessive ataxia in whom the acquired causes are excluded. ARCA are frequently neglected in the differential diagnosis of adult-onset ataxias. Rising awareness of their clinical significance is important, not only because some of these disorders may be potentially treatable, but also for prognostic implications and inclusion of patients to future clinical trials with disease modifying agents.

Precision medicine for genetic childhood movement disorders

Increasingly effective targeted precision medicine is either already available or in development for a number of genetic childhood movement disorders. Patient-centred, personalized approaches include the repurposing of existing treatments for specific conditions and the development of novel therapies that target the underlying genetic defect or disease mechanism. In tandem with these scientific advances, close collaboration between clinicians, researchers, affected families, and stakeholders in the wider community will be key to successfully delivering such precision therapies to children with movement disorders. What this paper adds Precision medicine for genetic childhood movement disorders is developing rapidly. Accurate diagnosis, disease-specific outcome measures, and collaborative multidisciplinary work will accelerate the progress of such strategies.

Increased anxiety-like behaviour is an early symptom of vitamin E deficiency that is suppressed by adrenalectomy in rats

We previously reported that dietary vitamin E deficiency increased anxiety-like behaviour in rats exposed to social isolation. Here, we performed a detailed investigation of this phenomenon and its underlying mechanism. First, we fed Wistar rats with a vitamin E-free diet for 3 d, 1 week or 2 weeks and found an increase in anxiety-like behaviour after 1 and 2 weeks of vitamin E deficiency based on behavioural indicators. Next, we examined the effect of a control diet (150 mg all-racemic α-tocopheryl acetate/kg) on anxiety-like behaviours in rats that received a 4-week vitamin E-free diet. We found that increased anxiety-like behaviour was reversed to control levels after refeeding vitamin E for 7 d but not for 1 or 3 d. Further, anxiety-like behaviour increased or decreased gradually based on the amount of vitamin E intake; however, it had a quicker progression than physical symptoms of vitamin E deficiency. Moreover, rats fed with excess vitamin E (500 mg all-racemic α-tocopherol/kg diet) showed less anxiety-like behaviour than control rats, indicating that vitamin E supplementation is effective for preventing anxiety increase under social isolation stress. Since plasma corticosterone levels were higher in vitamin E-deficient rats, we investigated the effect of adrenalectomy on anxiety-like behaviour and found that adrenal hormones played an essential role in the increased anxiety-like behaviour induced by vitamin E deficiency. In conclusion, increased anxiety-like behaviour is a symptom that emerges earlier than physical vitamin E deficiency and is caused by adrenal hormone-dependent mechanisms.

Genome wide association studies for treatment-related adverse effects of pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric hematological malignancy; notwithstanding the success of ALL therapy, severe adverse drugs effects represent a serious issue in pediatric oncology, because they could be both an additional life threatening condition for ALL patients per se and a reason to therapy delay or discontinuation with important fallouts on final outcome. Cancer treatment-related toxicities have generated a significant need of finding predictive pharmacogenomic markers for the a priori identification of at risk patients. In the era of precision medicine, high throughput genomic screening such as genome wide association studies (GWAS) might provide useful markers to tailor therapy intensity on patients' genetic profile. Furthermore, these findings could be useful in basic research for better understanding the mechanistic and regulatory pathways of the biological functions associated with ALL treatment toxicities. The purpose of this review is to give an overview of high throughput genomic screening of the last 10 years that had investigated the landscape of ALL treatment-associated toxicities. This article is categorized under: Cancer > Genetics/Genomics/Epigenetics.

Vitamin E: necessary nutrient for neural development and cognitive function

Vitamin E, discovered in 1922, is essential for pregnant rats to carry their babies to term. However, 100 years later, the molecular mechanisms for the vitamin E requirement during embryogenesis remain unknown. Vitamin E's role during pregnancy has been difficult to study and thus, a vitamin E-deficient (E-) zebrafish embryo model was developed. Vitamin E deficiency in zebrafish embryos initiates lipid peroxidation, depletes a specific phospholipid (DHA-phosphatidyl choline), causes secondary deficiencies of choline, betaine and critical thiols (such as glutathione), and dysregulates energy metabolism. Vitamin E deficiency not only distorts the carefully programmed development of the nervous system, but it leads to defects in several developing organs. Both the α-tocopherol transfer protein and vitamin E are necessary for embryonic development, neurogenesis and cognition in this model and likely in human embryos. Elucidation of the control mechanisms for the cellular and metabolic pathways involved in the molecular dysregulation caused by vitamin E deficiency will lead to important insights into abnormal neurogenesis and embryonic malformations.

Integrating disease and drug-related phenotypes for improved identification of pharmacogenomic variants

Aim: To improve the identification and interpretation of pharmacogenetic variants through the integration of disease and drug-related traits. Materials & methods: We hypothesized that integrating genome-wide disease and pharmacogenomic data may drive new insights into drug toxicity and response by identifying shared genetic architecture. Pleiotropic variants were identified using a methodological framework incorporating colocalization analysis. Results: Using genome-wide association studies summary statistics from the UK Biobank, European Bioinformatics Institute genome-wide association studies catalog and the Pharmacogenomics Research Network, we validated pleiotropy at the ABCG2 locus between allopurinol response and gout and identified novel pleiotropy between antihypertensive-induced new-onset diabetes, Crohn's disease and inflammatory bowel disease at the IL18RAP/SLC9A4 locus. Conclusion: New mechanistic insights and genetic loci can be uncovered by identifying pleiotropy between disease and drug-related traits.

Sensory neuronopathies: new genes, new antibodies and new concepts

Degeneration of dorsal root ganglia (DRG) and its central and peripheral projections provokes sensory neuronopathy (SN), a rare disorder with multiple genetic and acquired causes. Clinically, patients with SN usually present with proprioceptive ataxia, patchy and asymmetric sensory abnormalities, widespread areflexia and no weakness. Classic causes of SN include cancer, Sjögren's syndrome, vitamin deficiency, chemotherapy, mitochondrial disorders and Friedreich ataxia. More recently, new genetic and dysimmune disorders associated with SN have been described, including RFC1 gene-linked cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) and anti-FGFR3 antibodies. In this review, we detail the pathophysiology of DRG degeneration, and the genetic and acquired causes of SN, with a special focus on the recently described CANVAS and anti-FGFR3 antibodies. We also propose a user-friendly and easily implemented SN diagnostic strategy.

Synthetic α-Tocopherol, Compared with Natural α-Tocopherol, Downregulates Myelin Genes in Cerebella of Adolescent Ttpa-null Mice

BACKGROUND

Vitamin E (α-tocopherol; α-T) deficiency causes spinocerebellar ataxia. α-T supplementation improves neurological symptoms, but little is known about the differential bioactivities of natural versus synthetic α-T during early life.

OBJECTIVE

We assessed the effects of dietary α-T dose and source on tissue α-T accumulation and gene expression in adolescent α-tocopherol transfer protein-null (Ttpa-/-) mice.

METHODS

Three-week-old male Ttpa-/- mice (n  = 7/group) were fed 1 of 4 AIN-93G-based diets for 4 wk: vitamin E deficient (VED; below α-T limit of detection); natural α-T, 600 mg/kg diet (NAT); synthetic α-T, 816 mg/kg diet (SYN); or high synthetic α-T, 1200 mg/kg diet (HSYN). Male Ttpa+/+ littermates fed AIN-93G [75 mg synthetic α-T (CON)] served as controls (n  = 7). At 7 wk of age, tissue α-T concentrations and stereoisomer profiles were measured for all groups. RNA-sequencing was performed on cerebella of Ttpa-/- groups.

RESULTS

Ttpa-/- mice fed VED had undetectable brain α-T concentrations. Cerebral cortex α-T concentrations were greater in Ttpa-/- mice fed NAT (9.1 ± 0.7 nmol/g), SYN (10.8 ± 1.0 nmol/g), and HSYN (13.9 ± 1.6 nmol/g) compared with the VED group but were significantly lower than in Ttpa+/+ mice fed CON (24.6 ± 1.2 nmol/g) (P < 0.001). RRR-α-T was the predominant stereoisomer in brains of Ttpa+/+ mice (∼40%) and Ttpa-/- mice fed NAT (∼94%). α-T stereoisomer composition was similar in brains of Ttpa-/- mice fed SYN and HSYN (2R: ∼53%; 2S: ∼47%). Very few of the 16,774 genes measured were differentially expressed. However, compared with the NAT diet, HSYN significantly downregulated 20 myelin genes, including 2 transcription factors: SRY-box transcription factor 10 (Sox10) and myelin regulatory factor (Myrf), and several downstream target genes (false discovery rate <0.05).

CONCLUSIONS

High-dose synthetic α-T compared with natural α-T alters myelin gene expression in the adolescent mouse cerebellum, which could lead to morphological and functional abnormalities later in life.

Movement Disorders in Genetic Pediatric Ataxias

Background

Genetic pediatric ataxias are heterogeneous rare disorders, mainly inherited as autosomal-recessive traits. Most forms are progressive and lack effective treatment, with relevant socioeconomical impact. Albeit ataxia represents the main clinical feature, the phenotype can be more complex, with additional neurological and nonneurological signs being described in several forms.

Methods and Results

In this review, we provide an overview of the occurrence and spectrum of movement disorders in the most relevant forms of childhood-onset genetic ataxias. All types of hypokinetic and hyperkinetic movement disorders of variable severity have been reported. Movement disorders occasionally represent the symptom of onset, predating ataxia even of a few years and therefore challenging an early diagnosis. Their pathogenesis still remains poorly defined, as it is not yet clear whether movement disorders may directly relate to the cerebellar pathology or result from an extracerebellar dysfunction, including the basal ganglia.

Conclusion

Recognition of the complete movement disorder phenotype in genetic pediatric ataxias has important implications for diagnosis, management, and genetic counseling.

Association of Circulating Retinol and α-TOH Levels with Cognitive Function in Aging Subject with Type 2 Diabetes Mellitus

OBJECTIVES

Malnutrition of vitamin A (retinol) and vitamin E (α-tocopherol, α-TOH) was observed in type 2 diabetes mellitus (T2DM) or dementia patients. However, how these vitamins affect cognitive function of subjects with T2DM was seldom reported. The objective of this study was to determine the association of circulating retinol and α-TOH with cognition in aging subjects with T2DM.

METHODS

A total of 448 T2DM subjects and 448 age, gender and education matched control subjects (aged 55-75 years) were included in the study. Demographic characters of the participants were collected. Food frequency questionnaire (FFQ) method was used to collect dietary intake information. To assess the status of cognition, the MoCA test was used. Circulating retinol and α-TOH levels were compared between T2DM and non-T2DM subjects. Correlation of circulating retinol and α-TOH levels with cognitive function was analyzed in T2DM subjects. The effect of serum retinol and α-TOH levels on the risk of MCI in T2DM patients was explored.

RESULTS

We found that T2DM-MCI subjects demonstrate lower serum retinol level than T2DM-nonMCI subjects (P < 0.01). Serum retinol level was positively correlated to cognitive function in T2DM subject (P < 0.05). T2DM subjects with higher circulating retinol level demonstrate higher cognitive scores in visual and executive, attention, language, memory and delayed recall domains (P < 0.05).

CONCLUSION

Diminished circulating retinol predicts an increased risk of MCI in T2DM patients. Our findings provide suggestions that optimal retinol nutritional status might benefit cognition and decrease the risk of MCI in aging subjects with T2DM.

The Classification of Autosomal Recessive Cerebellar Ataxias: a Consensus Statement from the Society for Research on the Cerebellum and Ataxias Task Force

There is currently no accepted classification of autosomal recessive cerebellar ataxias, a group of disorders characterized by important genetic heterogeneity and complex phenotypes. The objective of this task force was to build a consensus on the classification of autosomal recessive ataxias in order to develop a general approach to a patient presenting with ataxia, organize disorders according to clinical presentation, and define this field of research by identifying common pathogenic molecular mechanisms in these disorders. The work of this task force was based on a previously published systematic scoping review of the literature that identified autosomal recessive disorders characterized primarily by cerebellar motor dysfunction and cerebellar degeneration. The task force regrouped 12 international ataxia experts who decided on general orientation and specific issues. We identified 59 disorders that are classified as primary autosomal recessive cerebellar ataxias. For each of these disorders, we present geographical and ethnical specificities along with distinctive clinical and imagery features. These primary recessive ataxias were organized in a clinical and a pathophysiological classification, and we present a general clinical approach to the patient presenting with ataxia. We also identified a list of 48 complex multisystem disorders that are associated with ataxia and should be included in the differential diagnosis of autosomal recessive ataxias. This classification is the result of a consensus among a panel of international experts, and it promotes a unified understanding of autosomal recessive cerebellar disorders for clinicians and researchers.

Autosomal Recessive Cerebellar Ataxias: Paving the Way toward Targeted Molecular Therapies

Autosomal-recessive cerebellar ataxias (ARCAs) comprise a heterogeneous group of rare degenerative and metabolic genetic diseases that share the hallmark of progressive damage of the cerebellum and its associated tracts. This Review focuses on recent translational research in ARCAs and illustrates the steps from genetic characterization to preclinical and clinical trials. The emerging common pathways underlying ARCAs include three main clusters: mitochondrial dysfunction, impaired DNA repair, and complex lipid homeostasis. Novel ARCA treatments might target common hubs in pathogenesis by modulation of gene expression, stem cell transplantation, viral gene transfer, or interventions in faulty pathways. All these translational steps are addressed in current ARCA research, leading to the expectation that novel treatments for ARCAs will be reached in the next decade.

Peripheral nerve disease secondary to systemic conditions in children

This review is an overview of systemic conditions that can be associated with peripheral nervous system dysfunction. Children may present with neuropathic symptoms for which, unless considered, a causative systemic condition may not be recognized. Similarly, some systemic conditions may be complicated by comorbid peripheral neuropathies, surveillance for which is indicated. The systemic conditions addressed in this review are critical illness polyneuropathy, chronic renal failure, endocrine disorders such as insulin-dependent diabetes mellitus and multiple endocrine neoplasia type 2b, vitamin deficiency states, malignancies and reticuloses, sickle cell disease, neurofibromatosis, connective tissue disorders, bowel dysmotility and enteropathy, and sarcoidosis. In some disorders presymptomatic screening should be undertaken, while in others there is no benefit from early detection of neuropathy. In children with idiopathic peripheral neuropathies, systemic disorders such as celiac disease should be actively excluded. While management is predominantly focused on symptomatic care through pain control and rehabilitation, some neuropathies improve with effective control of the underlying etiology and in a small proportion a more targeted approach is possible. In conclusion, peripheral neuropathies can be associated with a diverse range of medical conditions and unless actively considered may not be recognized and inadequately managed.

Anti-Oxidant Drugs: Novelties and Clinical Implications in Cerebellar Ataxias

BACKGROUND

Hereditary cerebellar ataxias are a group of disorders characterized by heterogeneous clinical manifestations, progressive clinical course, and diverse genetic causes. No disease modifying treatments are yet available for many of these disorders. Oxidative stress has been recurrently identified in different progressive cerebellar diseases, and it represents a widely investigated target for treatment.

OBJECTIVE

To review the main aspects and new perspectives of antioxidant therapy in cerebellar ataxias ranging from bench to bedside.

METHOD

This article is a summary of the state-of-the-art on the use of antioxidant molecules in cerebellar ataxia treatments. It also briefly summarizes aspects of oxidative stress production and general characteristics of antioxidant compounds.

RESULTS

Antioxidants represent a vast category of compounds; old drugs have been extensively studied and modified in order to achieve better biological effects. Despite the vast body of literature present on the use of antioxidants in cerebellar ataxias, for the majority of these disorders conclusive results on the efficacy are still missing.

CONCLUSION

Antioxidant therapy in cerebellar ataxias is a promising field of investigations. To achieve the success in identifying the correct treatment more work needs to be done. In particular, a combined effort is needed by basic scientists in developing more efficient molecules, and by clinical researchers together with patients communities, to run clinical trials in order to identify conclusive treatments strategies.

Reuniting overnutrition and undernutrition, macronutrients, and micronutrients

Over-nutrition and its late consequences are a dominant theme in medicine today. In addition to the health hazards brought on by over-nutrition, the medical community has recently accumulated a roster of health benefits with obesity, grouped under "obesity paradox." Throughout the world and throughout history until the 20^th century, under-nutrition was a dominant evolutionary force. Under-nutrition brings with it a mix of benefits and detriments that are opposite to and continuous with those of over-nutrition. This continuum yields J-shaped or U-shaped curves relating body mass index to mortality. The overweight have an elevated risk of dying in middle age of degenerative diseases while the underweight are at increased risk of premature death from infectious conditions. Micronutrient deficiencies, major concerns of nutritional science in the 20^th century, are being neglected. This "hidden hunger" is now surprisingly prevalent in all weight groups, even among the overweight. Because micronutrient replacement is safe, inexpensive, and predictably effective, it is now an exceptionally attractive target for therapy across the spectrum of weight and age. Nutrition-related conditions worthy of special attention from caregivers include excess vitamin A, excess vitamin D, and deficiency of magnesium.

Diminished circulating retinol and elevated α-TOH/retinol ratio predict an increased risk of cognitive decline in aging Chinese adults, especially in subjects with ApoE2 or ApoE4 genotype

OBJECTIVE

The current study evaluated the relationship between circulating fat soluble vitamin status and cognition in aging Chinese population.

METHODS

A cross-sectional study was carried out in 1754 community residents aged 55-80 years aiming to evaluate the relationship between circulating α-tocopherol and retinol status and cognition. The effect of ApoE genetic polymorphism on the relationship between vitamins and cognition was also explored.

RESULTS

Our results indicated that serum retinol status positively correlated with cognitive performance; while, serum α-tocopherol (α-TOH)/retinol ratio negatively correlated with cognitive performance. Mild cognitive impairment (MCI) subject demonstrated higher serum α-TOH status (P < 0.05), α-TOH/retinol ratio (P < 0.01) and lower retinol status (P < 0.01) than normal subjects. Subjects with ApoE4 genotype have lower serum retinol level (P < 0.05) and higher α-TOH/retinol ratio (P < 0.01) than subjects with ApoE3 genotype. MCI-ApoE4 carriers demonstrated the worst cognitive performance (P < 0.05) and exhibited higher serum TC, α-TOH and α-TOH/retinol ratio levels (P < 0.05), and lower LDL-C, retinol and lipid-adjusted retinol status (P < 0.05). MCI-ApoE2 subjects showed higher serum TC, HDL-C content and α-TOH/retinol ratio (P < 0.05); and lower serum retinol and lipid-adjusted retinol status (P < 0.05).

CONCLUSION

Lower circulating retinol and higher α-TOH/retinol ratio potentially predicts an increased risk for the development of cognitive decline in aging Chinese adults. ApoE2 or E4 carriers with higher circulating α-TOH/retinol ratio infer poor cognitive performance and an increased risk of developing MCI.