A new genetic cause of spastic ataxia: the p.Glu415Lys variant in TUBA4A

Tubulinopathies encompass neurodevelopmental disorders caused by mutations in genes encoding for different isotypes of α- and β-tubulins, the structural components of microtubules. Less frequently, mutations in tubulins may underlie neurodegenerative disorders. In the present study, we report two families, one with 11 affected individuals and the other with a single patient, carrying a novel, likely pathogenic, variant (p. Glu415Lys) in the TUBA4A gene (NM_006000). The phenotype, not previously described, is that of spastic ataxia. Our findings widen the phenotypic and genetic manifestations of TUBA4A variants and add a new type of spastic ataxia to be taken into consideration in the differential diagnosis.

Ataxia and spastic paraplegia in mitochondrial disease

Degenerative ataxias and hereditary spastic paraplegias (HSPs) form a continuous, often overlapping disease spectrum sharing not only phenotypic features and underlying genes, but also cellular pathways and disease mechanisms. Mitochondrial metabolism presents a major molecular theme underlying both multiple ataxias and HSPs, thus indicating a heightened vulnerability of Purkinje cells, spinocerebellar tracts, and motor neurons to mitochondrial dysfunction, which is of particular interest for translational approaches. Mitochondrial dysfunction might be the primary (upstream) or secondary (downstream) result of a genetic defect, with underlying genetic defects in nuclear-encoded genes being much more frequent than in mtDNA genes in both, ataxias and HSPs. Here, we outline the substantial number of ataxias, spastic ataxias and HSPs caused by mutated genes implicated in (primary or secondary) mitochondrial dysfunction, highlighting several key "mitochondrial" ataxias and HSPs which are of particular interest for their frequency, pathogenesis and translational opportunities. We then showcase prototypic mitochondrial mechanisms by which disruption of these ataxia and HSP genes contributes to Purkinje cells or corticospinal neuron dysfunction, thus elucidating hypotheses on Purkinje cells and corticospinal neuron vulnerability to mitochondrial dysfunction.

A Diagnostic Approach to Spastic ataxia Syndromes

Spastic ataxia is characterized by the combination of cerebellar ataxia with spasticity and other pyramidal features. It is the hallmark of some hereditary ataxias, but it can also occur in some spastic paraplegias and acquired conditions. It often presents with heterogenous clinical features with other neurologic and non-neurological symptoms, resulting in complex phenotypes. In this review, the differential diagnosis of spastic ataxias are discussed and classified in accordance with inheritance. Establishing an organized classification method based on mode inheritance is fundamental for the approach to patients with these syndromes. For each differential, the clinical features, neuroimaging and genetic aspects are reviewed. A diagnostic approach for spastic ataxias is then proposed.

Heterozygous UCHL1 loss-of-function variants cause a neurodegenerative disorder with spasticity, ataxia, neuropathy, and optic atrophy

PURPOSE

Biallelic variants in UCHL1 have been associated with a progressive early-onset neurodegenerative disorder, autosomal recessive spastic paraplegia type 79. In this study, we investigated heterozygous UCHL1 variants on the basis of results from cohort-based burden analyses.

METHODS

Gene-burden analyses were performed on exome and genome data of independent cohorts of patients with hereditary ataxia and spastic paraplegia from Germany and the United Kingdom in a total of 3169 patients and 33,141 controls. Clinical data of affected individuals and additional independent families were collected and evaluated. Patients' fibroblasts were used to perform mass spectrometry-based proteomics.

RESULTS

UCHL1 was prioritized in both independent cohorts as a candidate gene for an autosomal dominant disorder. We identified a total of 34 cases from 18 unrelated families, carrying 13 heterozygous loss-of-function variants (15 families) and an inframe insertion (3 families). Affected individuals mainly presented with spasticity (24/31), ataxia (28/31), neuropathy (11/21), and optic atrophy (9/17). The mass spectrometry-based proteomics showed approximately 50% reduction of UCHL1 expression in patients' fibroblasts.

CONCLUSION

Our bioinformatic analysis, in-depth clinical and genetic workup, and functional studies established haploinsufficiency of UCHL1 as a novel disease mechanism in spastic ataxia.

Clinical and Molecular Findings of Autosomal Recessive Spastic Ataxia of Charlevoix Saguenay: an Iranian Case Series Expanding the Genetic and Neuroimaging Spectra

Autosomal recessive spastic ataxia of Charlevoix Saguenay (ARSACS) is now increasingly identified from all countries over the world, possibly rendering it one of the most common autosomal recessive ataxias. Here, we selected patients harboring SACS variants, the causative gene for ARSACS, in a large cohort of 137 patients with early-onset ataxia recruited from May 2019 to May 2021 and were referred to the ataxia clinic. Genetic studies were performed for 111 out of 137 patients (81%) which led to a diagnostic rate of 72.9% (81 out of 111 cases). Ten patients with the molecular diagnosis of ARSACS were identified. We investigated the phenotypic and imaging spectra of all confirmed patients with ARSACS. We also estimated the frequency of ARSACS in this cohort and described their clinical and genetic findings including seven novel variants as well as novel neuroimaging findings. While the classic clinical triad of ARSACS is progressive cerebellar ataxia, spasticity, and sensorimotor polyneuropathy, it is not a constant feature in all patients. Sensorimotor axonal-demyelinating neuropathy was detected in all of our patients, but spasticity and extensor plantar reflex were absent in 50% (5/10). In all patients, brain magnetic resonance imaging (MRI) showed symmetric linear hypointensities in the pons (pontine stripes) and anterior superior cerebellar atrophy as well as a hyperintense rim around the thalami (thalamic rim). Although infratentorial arachnoid cyst has been reported in ARSACS earlier, we report anterior temporal arachnoid cyst in two patients for the first time, indicating that arachnoid cyst may be an associated imaging feature of ARSACS. We also extended molecular spectrum of ARSACS by presenting 8 pathogenic and one variant of unknown significance (VUS) sequence variants, which 7 of them have not been reported previously. MetaDome server confirmed that the identified VUS variant was in the intolerant regions of sacsin protein encoded by SACS.

A novel compound heterozygous SPG7 variant is associated with progressive spastic ataxia and persecutory delusions found in Chinese patients: two case reports

BACKGROUND

Hereditary spastic paraplegia 7 (SPG7) is one of the subtypes of autosomal-recessive hereditary spastic paraplegia, which is a clinically heterogeneous neurodegenerative disorder. SPG7 often displays a complicated phenotype, including optic atrophy, ophthalmoparesis, and impaired emotional communication. In the Chinese population, sporadic cases of SPG7 variant-associated spastic ataxia are rarely reported.

CASE PRESENTATION

We carefully analysed the clinical features, imaging and genetic tests of two sporadic patients with SPG7, both from the Hebei region of China. One patient presented with progressive bilateral lower limb weakness, spastic-ataxia and no cognitive impairment. Brain MRI revealed mild cerebellar atrophy. Genetic analysis revealed c.1150_1151insCTAC (p.G384Afs*13) frameshift variant and exon1-3 heterozygous deletion. The other patient presented with progressive bilateral lower limb weakness, ataxia, dysarthria and a mild psychosis associated with persecutory delusions, which drew almost no attention, in addition to mild cognitive impairments characterized by a decrease in verbal memory and executive function. Genetic analysis identified two heterozygous variants in the SPG7 gene: c.1150_1151insCTAC (p.G384Afs*13) and c.1496delC (p.Q500Sfs*13).

CONCLUSIONS

The c.1496delC (p.Q500Sfs*13) variant in exon 11 has not been reported before. The c.1150_1151insCTAC variant is speculated to be a hotspot variant in the Chinese population. Patients with SPG7 may have cognitive impairments and psychosis, displaying specific characteristics, which should be of concern.

Transcriptomic characterization of tissues from patients and subsequent pathway analyses reveal biological pathways that are implicated in spastic ataxia

BACKGROUND

Spastic ataxias (SAs) encompass a group of rare and severe neurodegenerative diseases, characterized by an overlap between ataxia and spastic paraplegia clinical features. They have been associated with pathogenic variants in a number of genes, including GBA2. This gene codes for the non-lysososomal β-glucosylceramidase, which is involved in sphingolipid metabolism through its catalytic role in the degradation of glucosylceramide. However, the mechanism by which GBA2 variants lead to the development of SA is still unclear.

METHODS

In this work, we perform next-generation RNA-sequencing (RNA-seq), in an attempt to discover differentially expressed genes (DEGs) in lymphoblastoid, fibroblast cell lines and induced pluripotent stem cell-derived neurons derived from patients with SA, homozygous for the GBA2 c.1780G > C missense variant. We further exploit DEGs in pathway analyses in order to elucidate candidate molecular mechanisms that are implicated in the development of the GBA2 gene-associated SA.

RESULTS

Our data reveal a total of 5217 genes with significantly altered expression between patient and control tested tissues. Furthermore, the most significant extracted pathways are presented and discussed for their possible role in the pathogenesis of the disease. Among them are the oxidative stress, neuroinflammation, sphingolipid signaling and metabolism, PI3K-Akt and MAPK signaling pathways.

CONCLUSIONS

Overall, our work examines for the first time the transcriptome profiles of GBA2-associated SA patients and suggests pathways and pathway synergies that could possibly have a role in SA pathogenesis. Lastly, it provides a list of DEGs and pathways that could be further validated towards the discovery of disease biomarkers.

Novel detection of mutation in the TECPR2 gene in a Chinese hereditary spastic paraplegia 49 patient: a case report

Background

Hereditary spastic paraplegia 49 (HSP49) is an autosomal recessive genetic disease first discovered in 2012; and which the mutation primarily affects Bukharian Jewish patients.

Case presentation

The present case reports the first instance of HSP49 detected in China. The patient had normal mental development and good athletic ability before 10 years old and presented with instable temperature, mental retardation, spastic ataxia, and paroxysmal convulsions. Genetic diagnosis was based on detection of whole exons and two heterozygous variants in the exon region of the TECPR2 gene: c.1729C > T and c.4189G > A. Mutations at these two sites have not been previously reported.

Conclusions

This case expands the gene mutation spectrum and clinical phenotypic characteristics of autosomal recessive HSP in China; moreover, it indicates differences in the clinical phenotype of HSP49 in different ethnicities. In addition, this reported provides further evidence regarding the effectiveness of targeted next-generation sequencing technology in improving the efficiency and diagnostic rate of genetic diagnosis of HSP.

POLR3A variants in hereditary spastic paraparesis and ataxia: clinical, genetic, and neuroradiological findings in a cohort of Italian patients

Mutations in POLR3A are characterized by high phenotypic heterogeneity, with manifestations ranging from severe childhood-onset hypomyelinating leukodystrophic syndromes to milder and later-onset gait disorders with central hypomyelination, with or without additional non-neurological signs. Recently, a milder phenotype consisting of late-onset spastic ataxia without hypomyelinating leukodystrophy has been suggested to be specific to the intronic c.1909 + 22G > A mutation in POLR3A. Here, we present 10 patients from 8 unrelated families with POLR3A-related late-onset spastic ataxia, all harboring the c.1909 + 22G > A variant. Most of them showed an ataxic-spastic picture, two a "pure" cerebellar phenotype, and one a "pure" spastic presentation. The non-neurological findings typically associated with POLR3A mutations were absent in all the patients. The main findings on brain MRI were bilateral hyperintensity along the superior cerebellar peduncles on FLAIR sequences, observed in most of the patients, and cerebellar and/or spinal cord atrophy, found in half of the patients. Only one patient exhibited central hypomyelination. The POLR3A mutations present in this cohort were the c.1909 + 22G > A splice site variant found in compound heterozygosity with six additional variants (three missense, two nonsense, one splice) and, in one patient, with a novel large deletion involving exons 14-18. Interestingly, this patient had the most "complex" presentation among those observed in our cohort; it included some neurological and non-neurological features, such as seizures, neurosensory deafness, and lipomas, that have not previously been reported in association with late-onset POLR3A-related disorders, and therefore further expand the phenotype.

Spastic paraplegia type 46: novel and recurrent GBA2 gene variants in a compound heterozygous Italian patient with spastic ataxia phenotype

INTRODUCTION

Spastic paraplegia type 46 (SPG46) is a rare autosomal recessive hereditary spastic paraplegia, caused by mutations in the non-lysosomal glucosylceramidase β2 (GBA2) gene. Worldwide, approximately twenty SPG46 families have been identified so far.

CASE REPORT

We describe a compound heterozygous Italian patient carrying a novel (p.Arg879Gln) and a recurrent (p.Arg399 *) GBA2 gene variant. The patient presented unsteady gait at age 2, and progressively manifested spastic-ataxia, scoliosis, mild intellectual decline, and bilateral cataract.

DISCUSSION

Clinical manifestations associated with GBA2 gene variants encompass a spectrum of overlapping phenotypes including cerebellar ataxia, spastic paraplegia, and Marinesco-Sjogren-like syndrome. We review previously reported cases of SPG46 and discuss possible genetic differential diagnosis.

Increasing involvement of CAPN1 variants in spastic ataxias and phenotype-genotype correlations

Spastic ataxias are rare neurogenetic disorders involving spinocerebellar and pyramidal tracts. Many genes are involved. Among them, CAPN1, when mutated, is responsible for a complex inherited form of spastic paraplegia (SPG76). We report the largest published series of 21 novel patients with nine new CAPN1 disease-causing variants and their clinical characteristics from two European university hospitals (Paris and Stockholm). After a formal clinical examination, causative variants were identified by next-generation sequencing and confirmed by Sanger sequencing. CAPN1 variants are a rare cause (~ 1.4%) of young-adult-onset spastic ataxia; however, together with all published cases, they allowed us to better describe the clinical and genetic spectra of this form. Truncating variants are the most frequent, and missense variants lead to earlier age at onset in favor of an additional deleterious effect. Cerebellar ataxia with cerebellar atrophy, dysarthria and lower limb weakness are often associated with spasticity. We also suggest that cognitive impairment and depression should be assessed specifically in the follow-up of SPG76 cases.

A novel PNPLA6 mutation in a Turkish family with intractable Holmes tremor and spastic ataxia

Autosomal recessive cerebellar ataxias are a group of rare neurological diseases with a genetic origin. Recently, the mutations in the PNPLA6 gene were suggested to lead to ataxia and also to other specific syndromes such as Boucher-Neuhauser (ataxia, hypogonadism, and chorioretinal dystrophy) or Gordon-Holmes Syndromes (ataxia, hypogonadism, and brisk reflexes) within a broad spectrum of neurodegenerative diseases. Here we report three patients from a single-family with a novel pathogenic mutation in the PNPLA6 gene which led to predominantly spastic-ataxia, and intractable Holmes tremor. The PNPLA6-related disease should be considered in the differential diagnosis of spastic-ataxias even in the absence of chorioretinal dystrophy, and hypogonadotropic hypogonadism. Further studies should unravel the factors which account for the phenotypic variability present in patients with PNPLA6 gene mutations.

Expanding the clinical and neuroimaging features of NKX6-2-related hereditary spastic ataxia type 8

Pathogenic variants in NKX6-2 gene causing autosomal recessive spastic ataxia type 8 with hypomyelinating leukodystrophy have been reported in few families around the world. In this study, we performed Whole Exome Sequencing and identified a novel missense variant, c.501C > G; p.(Phe167Leu), in two affected siblings with main manifestations of global developmental delay, motor regression, hypotonia, clonus in lower limbs and muscle bulk atrophy especially in the upper limbs, spasticity and contracture, scoliosis, hip dislocation, oculomotor apraxia, horizontal and vertical nystagmus. In addition, wrist and foot drop due to peripheral axonal neuropathy were observed in these patients as a new clinical finding and cerebellar white matter involvement in brain Magnetic Resonance Imaging (MRI) as new imaging finding. Therefore, we expanded the manifestations of NKX6-2-related disorders in this manuscript.

Broadening the phenotype of the TWNK gene associated Perrault syndrome

Background

Perrault syndrome is a genetically heterogenous, very rare disease, characterized clinically by sensorineural hearing loss, ovarian dysfunction and neurological symptoms. We present the case of a 33 years old female patient with TWNK-associated Perrault syndrome. The TWNK gene is coding the mitochondrial protein Twinkle and currently there are only two reports characterizing the phenotype of TWNK-associated Perrault syndrome. None of these publications reported about special brain MRI alterations and neuropathological changes in the muscle and peripheral nerves.

Case presentation

Our patients with TWNK-dependent Perrault syndrome had severe bilateral hypoacusis, severe ataxia, polyneuropathy, lower limb spastic paraparesis with pyramidal signs, and gonadal dysgenesis. Psychiatric symptoms such as depression and paranoia were present as well. Brain MRI observed progressive cerebellar hyperintensive signs associated with cerebellar, medulla oblongata and cervical spinal cord atrophy. Light microscopy of the muscle biopsy detected severe neurogenic lesions. COX staining was centrally reduced in many muscle fibers. Both muscle and sural nerve electron microscopy detected slightly enlarged mitochondria with abnormal cristae surrounded by lipid vacuoles. In the sural nerve, dystrophic axons had focally uncompacted myelin lamellae present. Genetic investigation revealed multiple mtDNA deletion and compound heterozygous mutations of the TWNK gene (c.1196 A > G, c.1358 G > A).

Conclusion

This study demonstrates that TWNK associated Perrault syndrome has a much broader phenotype as originally published. The coexistence of severe hypoacusis, spastic limb weakness, ataxia, polyneuropathy, gonadal dysgensia, hyperintense signals in the cerebellum and the presence of the mtDNA multiple deletion could indicate the impairment of the TWNK gene. This is the first report about pyramidal tract involvement and cerebellar MRI alteration associated with TWNK-related Perrault syndrome.

A novel homozygous SACS mutation identified by whole exome sequencing-genotype phenotype correlations of all published cases

ARSACS is an autosomal recessive disorder characterized by ataxia, spasticity, and polyneuropathy. A plethora of worldwide distributed mutations have been described so far. Here, we report two brothers, born to non-consanguineous parents, presenting with cerebellar ataxia and peripheral neuropathy. Whole-exome sequencing revealed the presence of a novel homozygous variant in the SACS gene. The variant was confirmed by Sanger sequencing and found at heterozygous state in both parents. This is the first reported mutation in this gene, in Greek population. This case report further highlights the growing trend of identifying genetic diseases previously restricted to single, ethnically isolated regions in many different ethnic groups worldwide. Additionally, we performed a systematic review of all published cases with SACs mutations. ARSACS seems to be an important cause of ataxia and many different types of mutations have been identified, mainly located in exon 10. We evaluated the mutation pathogenicity in all previously reported cases to investigate possible phenotype-genotype correlations. We managed to find a correlation between the pathogenicity of mutations, severity of the phenotype, and age of onset of ARSACS. Greater mutation numbers in different populations will be important and mutation-specific functional studies will be essential to identify the pathogenicity of the various ARSACS variants.

SYNE1-ataxia: Novel genotypic and phenotypic findings

INTRODUCTION

SYNE1 encodes nesprin-1, a scaffold protein which is involved in the binding between cytoskeleton, nuclear envelope and other subcellular compartments. In 2007, recessive truncating SYNE1 mutations have been linked to a genetic form of pure cerebellar ataxia with adult onset and mild phenotype. Subsequent reports described a number of patients with SYNE1-ataxia and widespread neurological involvement including features of motor neuron disease. Recently, heterozygote missense SYNE1 mutations have been associated with muscular disorders, such as Emery-Dreifuss muscular dystrophy, arthrogryposis multiplex congenita and dilated cardiomyopathy.

METHODS

Herein we describe novel genotypic and phenotypic findings in an independent cohort of 5 patients with SYNE1-ataxia referring to the Department of Neurology of the Innsbruck Medical University and performed a review of the related literature.

RESULTS

We report 3 novel mutations and describe for the first time myocardial involvement in a patient with a complicated spastic-ataxic phenotype and C-terminal mutation. In the literature, mutations associated with additional motor neuron signs spanned over the entire gene, but patients with a particularly severe phenotype and premature death bore C-terminal mutations.

CONCLUSION

Our findings support a genotype-phenotype correlation in SYNE1-ataxia and suggest the need for a systematic cardiologic evaluation in the setting of complicated spastic-ataxia phenotypes.

Nonneurological Involvement in Late-Onset Friedreich Ataxia (LOFA): Exploring the Phenotypes

Friedreich's ataxia (FDRA) is the most common inherited ataxia worldwide, caused by homozygous GAA expansions in the FXN gene. Patients usually have early onset ataxia, areflexia, Babinski sign, scoliosis and pes cavus, but at least 25 % of cases have atypical phenotypes. Disease begins after the age of 25 in occasional patients (late-onset Friedreich ataxia (LOFA)). Little is known about the frequency and clinical profile of LOFA patients. One hundred six patients with molecular confirmation of FDRA and followed in three Brazilian outpatient centers were enrolled. General demographics, GAA expansion size, age at onset, cardiac, endocrine, and skeletal manifestations were evaluated and compared between LOFA and classic FDRA (cFDRA) groups. We used Mann-Whitney and Fisher tests to compare means and proportions between groups; p values <0.05 were considered significant. LOFA accounted for 17 % (18/106) and cFDRA for 83 % (88/106) of the patients. There were 13 and 48 women in each group, respectively. LOFA patients were significantly older and had smaller GAA expansions. Clinically, LOFA group had a tendency toward lower frequency of diabetes/impaired glucose tolerance (5.8 vs. 17 %, p = 0.29) and cardiomyopathy (16.6 vs. 28.4 %, p = 0.38). Skeletal abnormalities were significantly less frequent in LOFA (scoliosis 22 vs. 61 %, p = 0.003, and pes cavus 22 vs.75 %, p < 0.001) as were spasticity and sustained reflexes, found in 22 % of LOFA patients but in none of the cFDRA patients (p = 0.001). LOFA accounts for 17 % of Brazilian FDRA patients evaluated herein. Clinically, orthopedic features and spasticity with retained reflexes are helpful tips to differentiate LOFA from cFDRA patients.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) - A Polish family with novel SACS mutations

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a rare hereditary ataxia, characterized by the triad of early-onset cerebellar ataxia, peripheral sensorimotor neuropathy and lower limb spasticity. Although ARSACS is increasingly reported worldwide, we present the first Polish family with a comprehensive clinical and neuropsychological assessment, harboring two novel mutations in the SACS gene. Our results demonstrate the variability in cognitive and behavioral profiles in ARSACS, which is in line with other heredodegenerative ataxias. One should be aware of ARSACS in cases of autosomally recessive inherited ataxias without common mutations.

A 30-year history of MPAN case from Russia

We present a patient with progressive spastic ataxia, with dystonia and anarthria undiagnosed until detailed genetic analysis revealed an MPAN mutation. Highlighting the worldwide MPAN distribution, a 30year history of absent diagnosis and the impact and cost saving of an early but detailed genetic analysis in complex progressive movement disorders, particularly the anarthric NBIA group.

STUB1/CHIP mutations cause Gordon Holmes syndrome as part of a widespread multisystemic neurodegeneration: evidence from four novel mutations

BACKGROUND

CHIP, the protein encoded by STUB1, is a central component of cellular protein homeostasis and interacts with several key proteins involved in the pathogenesis of manifold neurodegenerative diseases. This gives rise to the hypothesis that mutations in STUB1 might cause a far more multisystemic neurodegenerative phenotype than the previously reported cerebellar ataxia syndrome.

METHODS

Whole exome sequencing data-sets from n = 87 index subjects of two ataxia cohorts were screened for individuals with STUB1 mutations. In-depth phenotyping by clinical evaluation and neuroimaging was performed in mutation carriers.

RESULTS

We identified four novel STUB1 mutations in three affected subjects from two index families (frequency 2/87 = 2.3%). All three subjects presented with a severe multisystemic phenotype including severe dementia, spastic tetraparesis, epilepsy, and autonomic dysfunction in addition to cerebellar ataxia, plus hypogonadism in one index patient. Diffusion tensor imaging revealed degeneration of manifold supra- and infratentorial tracts.

CONCLUSIONS

Our findings provide clinical and imaging support for the notion that CHIP is a crucial converging point of manifold neurodegenerative processes, corresponding with its universal biological function in neurodegeneration. Further, our data reveal the second STUB1 family with ataxia plus hypogonadism reported so far, demonstrating that Gordon Holmes syndrome is indeed a recurrent manifestation of STUB1. However, it does not present in isolation, but as part of a broad multisystemic neurodegenerative process. This supports the notion that STUB1 disease should be conceptualized not by historical or clinical syndromic names, but as a variable multisystemic disease defined by disturbed function of the underlying STUB1 gene, which translates into a multidimensional gradual spectrum of variably associated clinical signs and symptoms.

A novel GBA2 gene missense mutation in spastic ataxia

Autosomal recessive cerebellar ataxias (ARCA) encompass a heterogeneous group of rare diseases that affect the cerebellum, the spinocerebellar tract and/or the sensory tracts of the spinal cord. We investigated a consanguineous Cypriot family with spastic ataxia, aiming towards identification of the causative mutation. Family members were clinically evaluated and studied at the genetic level. Linkage analysis at marker loci spanning known ARCA genes/loci revealed linkage to the APTX locus. Thorough investigation of the APTX gene excluded any possible mutation. Whole genome linkage screening using microsatellite markers and whole genome SNP homozygosity mapping using the Affymetrix Genome-Wide Human SNP Array 6.0 enabled mapping of the disease gene/mutation in this family to Chromosome 9p21.1-p13.2. Due to the large number of candidate genes within this region, whole-exome sequencing of the proband was performed and further analysis of the obtained data focused on the mapped interval. Further investigation of the candidate variants resulted in the identification of a novel missense mutation in the GBA2 gene. GBA2 mutations have recently been associated with hereditary spastic paraplegia and ARCA with spasticity. We hereby report a novel GBA2 mutation associated with spastic ataxia and suggest that GBA2 mutations may be a relatively frequent cause of ARCA.