Genetic etiology of a Chinese ataxia cohort: Expanding the mutational spectrum of hereditary ataxias.

INTRODUCTION: Hereditary ataxias demonstrate a high degree of clinical and genetic heterogeneity. Understanding the genetic etiology of hereditary ataxias is crucial for genetic counseling and clinical management. METHODS: The clinical and genetic data of patients with familial or sporadic ataxias who referred to our tertiary medical center were retrospectively analyzed. Probands in this study underwent SCA repeat expansion panel firstly to screen for repeat expansion SCAs; those with negative results had NGS-targeted panels or WES testing to detect conventional mutations. RESULTS: A total of 223 patients were enrolled from 206 families. 5 kinds of coexisting SCA repeat expansions were observed (SCA3/SCA17, SCA3/SCA8, SCA2/SCA8, SCA3/SCA12 and SCA8/SCA12) in 12 patients from 8 families, among which SCA2/SCA8, SCA8/SCA12 and SCA3/SCA12 were reported for the first time. The coexistence of expanded SCA3 with SCA17 alleles was the most common in our study. NGS identified pathogenic/likely pathogenic variants in 12 ataxia causative genes in 13 probands. Spastic paraplegia ataxia was the most common diagnosis. Six novel mutations were detected in five ataxia-related genes. CONCLUSION: Coexistence may not specific to a certain SCA subtype and the frequency might have been underestimated before. SCA repeat expansion panel should be considered in patients with overlapping SCA features. In addition, our study broadened the conventional mutation spectrum in ataxia-related genes. These results facilitate a better understanding of the genetic basis for hereditary ataxias.

Low-Titre GAD Antibody-Associated Late-Onset Cerebellar Ataxia with a Significant Clinical Response to Intravenous Immunoglobulin Treatment.

Antiglutamic acid decarboxylase antibody-associated cerebellar ataxia (GAD-Abs CA) is a rare, but increasingly detected, autoimmune neurological disorder characterized by the clinical presence of a cerebellar syndrome concomitant with positive GAD-Abs levels in serum and cerebrospinal fluid (CSF). It represents 3% of all immune-mediated sporadic CAs. Low-titre GAD-Abs CA is an even rarer subtype of GAD-Abs CA. We report on a 68-year-old woman with a 3-year history of progressive gait ataxia. In addition to the modified Rankin Scale (mRS), we used two other objective scales to evaluate CA severity, i.e. the International Cooperative Ataxia Rating Scale (ICARS) and the Scale for Assessment and Rating of Ataxia (SARA). Series of CT and MRI showed atrophy of the cerebellum. Except for the glycated haemoglobin (HbA1c) levels, all other routine laboratory examinations were within normal limits. Autoimmune laboratory examinations showed positive (25.8 U/mL) serum GAD-Abs levels. The GAD antibody index was <1.0. The CSF analysis showed no oligoclonal immunoglobulin bands. Intravenous immunoglobulin (IVIg) therapy was started and significant improvement was observed. The diagnosis of low-titre GAD-Abs CA was established.

Gluten ataxia of sporadic and hereditary cerebellar ataxia in patients from mainland China.

BACKGROUND: Gluten sensitivity (GS) is a spectrum of disorders with diverse manifestations. Recent evidence suggests that ataxia may be the only manifestation of GS and that it may be one of the causes of sporadic ataxia. AIM: To investigate the prevalence of gluten ataxia among patients with ataxia in China. MATERIALS AND METHODS: Serum levels of anti-gliadin, anti-transglutaminase 2 (TG2), and anti-transglutaminase 6 (TG6) antibodies measured in 125 patients with ataxia (100 patients with sporadic ataxia and 25 patients with hereditary ataxia) and 51 healthy controls by enzyme-linked immunosorbent assay (ELISA). RESULTS: The serum concentrations of anti-gliadin, anti-TG2 IgG, IgA, and TG6-IgG antibodies were elevated in ataxia patients, but the increase was not statistically significant. However, TG6-IgA serum levels were significantly higher in sporadic ataxia as compared to those in healthy controls (P < 0.05). CONCLUSIONS: These results provide evidence that sporadic ataxia in a subgroup of patients may be due to gluten ataxia in mainland China. Measurement of serum anti-TG6 antibodies along with anti-TG2 and anti-gliadin antibodies may be useful for diagnosing gluten ataxia.

[Astragalus membranaceus promote expression of insulin-like growth factor 1 in rat model of olivo-cerebellar degeneration].

OBJECTIVE: To observe the effect of Astragalus membranaceus (AM) on insulin-like growth factor 1 (IGF-1) expression in a rat model of olivo-cerebellar degeneration and assess the neuroprotective actions of AM meanwhile. METHOD: Rats model of olivo-cerebellar degeneration was established by using 3-acetylpyridine. The effect of AM on the expression of Calbindin D-28K in inferior olive (IO) neurons by immunohistochemistry, the serum IGF-1 level by Elisa, the IGF-1 mRNA level in the cerebellum by RT-PCR were detected respectively. RESULT: AM effectively improve the serum IGF-1 level, Cerebellar IGF-1 mRNA level and the survival of the 10 neurons in a rat model of olivo-cerebellar degeneration, even at a lower dose (9 g x kg(-1)), and the effect was in a dose-dependent manner. CONCLUSION: AM could effectively upregulate the IGF-1 expression in the rat model of olivo-cerebellar degeneration, and have neuroprotective effect on IO neurons.

Longitudinal study of bone and calcium metabolism and fracture incidence in spinocerebellar degeneration.

Little is known about bone and calcium metabolism and fracture incidence in spinocerebellar degeneration (SCD) despite frequent falls and immobilization. To address bone and calcium metabolism and fracture incidence in SCD, we conducted a 10-year prospective study in a cohort of adult patients with SCD. Bone mineral density (BMD) and serum levels of ionized calcium, parathyroid hormone, 25-hydroxyvitamin D, and pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP) were followed in 110 patients with SCD for 10 years. Age-matched healthy volunteers (n = 110) served as controls. At baseline, the SCD patients had a low BMD with high levels of serum ionized calcium and ICTP which correlated with the degree of immobilization (Barthel index). Over 10 years, serum 25-hydroxyvitamin D decreased to the osteomalacic level (<5 ng/ml), and calcium and ICTP further increased in accordance with a decreased Barthel index score. The BMD decreased by 15.2% in men and by 24.6% in women. The incidence of fractures in the patients was significantly higher as compared with the control group (men 8/49 vs. 1/42, p = 0.0428; women 16/49 vs. 2/48, p = 0.0026). Over 10 years, the BMD was significantly reduced in the SCD patients, particularly in women, which increased the risk of a fracture. Vitamin D deficiency due to sunlight deprivation, increased bone resorption due to immobilization, and frequent falls are probable causes of osteoporosis and fractures in these patients. Hypovitaminosis D and increased bone resorption may be corrected readily by the routine use of vitamin D supplements together with bisphosphonate.

Autosomal recessive ataxia with peripheral neuropathy and elevated AFP: novel mutations in SETX.

Mutations in the Senataxin gene (SETX) are associated with autosomal recessive ataxia-ocular apraxia 2 (AOA2) and autosomal dominant juvenile ALS (ALS4). Here, the authors describe novel homozygous missense mutations in SETX, M274I, and R1294C, found in two siblings with ataxia, peripheral neuropathy, and increased serum alpha-fetoprotein level and three other siblings with heterozygous missense mutations who were neurologically asymptomatic. The results demonstrate that the double missense mutations are responsible for AOA2 but not for ALS4.

Detection of floccular hypometabolism in downbeat nystagmus by fMRI.

The authors evaluated floccular activity with fMRI during the performance of vertical smooth pursuit eye movements in four patients with downbeat nystagmus (DBN) due to cerebellar degeneration and in 16 healthy controls. Region of interest analysis revealed a significantly diminished activation of both floccular lobes during downward but not upward pursuit in DBN. These imaging data support the view that a functional deficiency of the flocculi in downward pursuit causes DBN.

Growth hormone response to arginine test distinguishes multiple system atrophy from Parkinson's disease and idiopathic late-onset cerebellar ataxia.

OBJECTIVE: Multiple system atrophy (MSA) is difficult to distinguish from idiopathic Parkinson's disease (PD) and idiopathic late-onset cerebellar ataxia (ILOCA). This study aimed to evaluate GH response to three different GH stimulation tests in order to establish a reliable test to differentiate these degenerative disorders. DESIGN: Twelve patients with MSA, 10 with PD, eight with ILOCA and 30 healthy controls entered the study. They were submitted to clonidine, arginine, and GH-releasing-hormone (GHRH) + arginine tests in a random manner on three different nonconsecutive days. The peak serum GH response was used as a primary variable for analysis of stimulation tests. By ROC analysis, the optimum cut-off level was considered as the cut-off with the maximal sum of sensitivity and specificity. RESULTS: After clonidine administration, GH peak was significantly lower in patients with MSA than in those with ILOCA (P < 0.05) and in the controls (P < 0.001). At the optimum cut-off level of 5 mU/l, the clonidine test distinguished patients with MSA from those with PD with a sensitivity and specificity of 78%. Moreover, this test distinguished patients with MSA from those with ILOCA with a sensitivity of 100% and a specificity of 75% at a cut-off level of 5 mU/l, and with a sensitivity of 75% and a specificity of 100% at the cut-off level of 7.6 mU/l. After arginine administration, the GH peak was significantly lower in patients with MSA than in those with ILOCA (P = 0.001) and in controls (P < 0.001). At the optimum cut-off level of 5 mU/l, the arginine test distinguished patients with MSA from those with PD with a sensitivity and a specificity of 100%. At a GH peak cut-off value of 3.6 mU/l the arginine test distinguished patients with MSA from those with ILOCA with a sensitivity and specificity of 100%. After GHRH + arginine administration, a significant GH increase was found in all groups of patients and controls. CONCLUSIONS: The GH response to arginine administration is impaired in MSA. Therefore, the arginine test showed the highest diagnostic accuracy to distinguish MSA from both PD and ILOCA, and could be used in the clinical practice of these neurodegenerative diseases.

Stimulation of growth hormone release in multiple system atrophy, Parkinson's disease and idiopathic cerebellar ataxia.

Clonidine has been proposed to differentiate multiple system atrophy (MSA) from idiopathic Parkinson's disease (IPD), as it does not increase growth hormone (GH) release in MSA. We studied GH release in response to clonidine in 7 IPD patients, 6 MSA patients, 4 patients affected by idiopathic late-onset cerebellar ataxia (ILOCA) and 8 healthy controls. In addition, we investigated the effects of GH releasing hormone plus arginine (GHRH-Arg) on GH release in the same patients. Both clonidine and GHRH-Arg raised serum GH levels in all groups examined. Clonidine failed to differentiate MSA from IPD and ILOCA. GHRH-Arg showed a lower increase of serum GH in MSA patients than in other groups, even if such difference was not statistically significant. We suggest that stimulation of GH release with GHRH-Arg rather than clonidine could differentiate MSA from IPD and ILOCA, but this hypothesis would need to be confirmed by further investigations.

Vitamin E deficiency due to chylomicron retention disease in Marinesco-Sjögren syndrome.

We report on 2 brothers (aged 19 and 12 years) with Marinesco-Sjögren syndrome who also had very low serum vitamin E concentrations with an absence of postprandial chylomicrons. The molecular study ruled out ataxia with isolated vitamin E deficiency, abetalipoproteinemia, and hypobetalipoproteinemia. The electron microscopy of the intestinal mucosa was consistent with a chylomicron retention disease. We speculate that both chylomicron retention disease and Marinesco-Sjögren syndrome are related to defects in a gene crucial for the assembly or secretion of the chylomicron particles, leading to very low serum levels of vitamin E.

Familial spinocerebellar ataxia with cerebellar atrophy, peripheral neuropathy, and elevated level of serum creatine kinase, gamma-globulin, and alpha-fetoprotein.

Here, we report a familial spinocerebellar ataxia (FSCA), which has clinical features similar to Friedreich's ataxia, an ataxia with isolated vitamin E deficiency, and ataxia telangiectasia. However, the serum levels of creatine kinase, gamma-globulin, and alpha-fetoprotein were elevated, and biochemical and genetic analyses ruled out diagnosis of these three ataxias as well as other FSCAs. Thus, this family is thought to have a new type of FSCA.

Optic disc edema associated with spinocerebellar degeneration.

A 58-year-old man presented with optic disc edema as a rare association with spinocerebellar degeneration (SCD). The patient also had chronic idiopathic intestinal pseudo-obstruction with hypoalbuminemia. No elevation of intraspinal pressure and no intracranial lesion was observed. The hypoalbuminemia reacted promptly to treatment, whereas the optic disc edema regressed gradually. An association between SCD and optic atrophy has often been described, but to our knowledge this is the first report of SCD in association with optic disc edema.

Clinical and molecular characteristics of a Brazilian family with spinocerebellar ataxia type 1.

The spinocerebellar ataxias (SCAs) are a clinically and genetically heterogeneous group of late onset neurodegenerative disorders. To date, seven different genes causing autosomal dominant SCA have been mapped: SCA1, SCA2, Machado-Joseph disease (MJD)SCA3, SCA4, SCA5, SCA7 and dentatorubropallidoluysian atrophy (DRPLA). Expansions of an unstable trinucleotide CAG repeat cause three of these disorders: SCA1, MJD/SCA3 and DRPLA. We studied one Brazilian family segregating an autosomal dominant type of SCA. A total of ten individuals were examined and tested for the presence of the SCA1, MJD and DRPLA mutations. Three individuals, one male, and two females, were considered affected based on neurological examination; ages at onset were 32, 36 and 41 years. The first complaint in all three patients was gait ataxia which progressed slowly over the years. Six individuals showed one allele containing an expanded CAG repeat in the SCA1 gene. The mean size of the expanded allele was 48.2 CAG units. Instability of the expanded CAG tract was seen in the two transmissions that were observed in this family. In both occasions there was a contraction of the CAG tract. Our study demonstrates that SCA1 occurs in the Brazilian population. In addition, our results stress the importance of molecular studies in the confirmation of diagnosis and for pre-symptomatic testing in SCAs.

Clinical and molecular characteristics of a brazilian family with spinocerebellar ataxia type 1

The spinocerebellar ataxias (SCAs) are a clinically and genetically heterogeneous group of late onset neurodegenerative disorders. To date, seven different genes causing autosomal dominant SCA have been mapped:SCA1,SCA2, Machado-Joseph disease(MJD)/SCA3,SCA4,SCA5,SCA7 and dentatorubropallidoluysian atrophy (DRPLA). Expansions of an unstable trinucleotide CAG repeat cause three of these disorders: SCA1, MJD/SCA3 and DRPLA. We studied one Brazilian family segregating an autosomal dominant type of SCA. A total of ten individuals were examined and tested for the presence of the SCA1, MJD and DRPLA mutations. Three individuals, one male and two females, were considered affected based on neurological examination; ages at onset were: 32, 36 and 41 years. The first complaint in all three patients was gait ataxia which progressed slowly over the years. Six individuals showed one allele containing an expanded CAG repeat in the SCA1 gene. The mean size of the expanded allele was 48.2 CAG units. Instability of the expanded CAG tract was seen in the two transmissions that were observed in this family. In both occasions there was a contraction of the CAG tract. Our study demonstrates that SCA1 occurs in the Brazilian population. In addition, our results stress the importance of molecular studies in the confirmation of diagnosis and for pre-symptomatic testing in SCAs.

Adult-onset spinocerebellar dysfunction caused by a mutation in the gene for the alpha-tocopherol-transfer protein.

BACKGROUND: Patients with isolated vitamin E deficiency have an impaired ability to incorporate alpha-tocopherol into lipoproteins in the liver and usually have symptoms and signs of spinocerebellar dysfunction before adolescence. Accumulated evidence suggests that the alpha-tocopherol-transfer protein, which is presumed to function in the intracellular transport of alpha-tocopherol, is abnormal in these patients. METHODS: We studied a patient from an isolated Japanese island who began to have ataxia, dysarthria, and sensory disturbances in the sixth decade of life. His serum vitamin E concentration was low (1.2 micrograms per milliliter [2.8 mumol per liter]). Exons of his gene for the alpha-tocopherol-transfer protein were analyzed by DNA sequencing. We also screened an additional 801 inhabitants of the island for the mutation. Both the normal and mutant alpha-to-copherol-transfer proteins were expressed in COS-7 cells and studied by immunoblot analysis and assay for alpha-tocopherol-transfer activity. RESULTS: The patient was homozygous for a point mutation that replaces histidine (CAT) with glutamine (CAG) at position 101 of the gene for the alpha-tocopherol-transfer protein. When expressed in COS-7 cells, the missense mutation produced a functionally defective alpha-tocopherol-transfer protein with approximately 11 percent of the transfer activity of the wild-type protein. Of the 801 island inhabitants examined, 21 were heterozygous for the His101Gln mutation. In all affected subjects, including the patient, this mutation cosegregated with an intron-sequence polymorphism. The heterozygotes were phenotypically normal and had serum vitamin E concentrations that were on average 25 percent lower than those of normal subjects (mean [+/- SD], 7.5 +/- 2.2 vs. 10.1 +/- 2.8 micrograms per milliliter [17.4 +/- 5.1 vs. 23.4 +/- 6.5 mumol per liter]; P = 0.002). CONCLUSIONS: alpha-Tocopherol-transfer protein is a determinant of serum vitamin E concentrations. An abnormality in this protein is a cause of spinocerebellar dysfunction.

Multiple pituitary hormone deficiencies in a patient with spinocerebellar ataxia: magnetic resonance imaging and hormonal studies.

Degenerative spinocerebellar ataxia has a rare association with hypogonadotropic hypogonadism. In this report we present the results of the detailed endocrine evaluation and magnetic resonance imaging in one such patient. A 20-year-old male with progressive cerebellar ataxia, hypogonadism, and short stature was investigated. Basal testing revealed hypogonadotropic hypogonadism (LH < 5 mU/L, FSH < 5 mU/L, testosterone 2.5 nM/L). There was no rise in LH after stimulation with LHRH, peak LH level being < 5 mU/L. Insulin hypoglycemia testing was consistent with GH deficiency, with peak GH being 3.2 mU/L. On TRH stimulation, there was no significant rise in prolactin, though the TSH response was normal. Magnetic resonance imaging revealed cerebellar atrophy. The anterior pituitary was atrophic, with a height of 1.4 mm. The posterior pituitary and the pituitary stalk were normal in size and position. This patient with degenerative spinocerebellar ataxia had multiple pituitary hormone deficiencies. The results of our endocrine evaluation and MR imaging lead us to believe that these deficits may result from a lesion at the level of the pituitary gland.

Serum lipoprotein fatty acid profile in hereditary ataxias.

We investigated the serum fatty acid profiles of cholesterol esters, phospholipids and triglycerides in 24 patients with Friedreich's disease and 16 patients with other forms of spinocerebellar degeneration. In 8 patients with Friedreich's disease we also analyzed the fatty acid profile of the lipoprotein fractions. We found no major differences in fatty acid profiles between ataxic patients and sex and age-matched controls; in particular there was no decrease of linoleic acid in Friedreich's disease. The level of linoleic acid in serum cholesterol esters decreased with increasing disability of patients.

Preliminary findings on the variation of serum apolipoprotein levels in neural degenerative disorders.

We measured six apolipoproteins (AI, AII, B, CII, CIII, and E) in the serum of patients with several kinds of neural diseases [diabetic neuropathy and neural degenerative disorders (motor neuron degenerative disorders, spinocerebellar degeneration, Parkinson's disease)], comparing them to the age-matched healthy controls using the immunoturbidimetric method. Statistically significant decreases of serum apo-AI, apo-A-II and increases of apo-CIII, apo-E were observed in neural degenerative diseases; and, particularly, higher apo-B and apo-CII concentrations were observed in diabetic neuropathy. Most neural degenerative disease showed lower apo-AII. However, in motor neuron degenerative disorders, higher apo C-II and apo-E were seen. Lower apo-AI was seen in spinocerebellar degeneration, and lower apo-AII was seen in Parkinson's disease. Higher apo-B, CII, and E levels were observed in females with spinocerebellar degeneration and Parkinson's disease, and lower apo-AII was seen in males with spinocerebellar disease.

Preliminary characterization of hereditary cerebellar ataxia in rats.

A spontaneous model of Purkinje cell degeneration in rats is described. Breeding data indicate that the condition is hereditary and not sex linked. The breeding colony has remained free of common murine pathogens, including parvovirus. In older rats with pronounced ataxia, the major lesions consisted of greatly reduced numbers or complete absence of Purkinje cells (PCs), particularly in the anterior lobe of the cerebellum. There was a decreased thickness and increased cellular density of the molecular layer and degeneration of the inferior olivary nuclei. Morphometric analysis indicated that the anterior lobes of affected rats were 52% smaller than those of normal rats. In young rats, before severe signs of ataxia had developed, microscopic changes were minimal. The preliminary findings are discussed in relationship to human cerebellar ataxias and mouse models of Purkinje cell degeneration.

Thiamine status in inherited degenerative ataxias.

Blood thiamine levels in ataxia patients were studied. No significant differences were found between 30 patients with Friedreich's ataxia and 29 patients with olivopontocerebellar atrophy (OPCA) compared with control subjects. Both OPCA and Friedreich's ataxia patients presented significantly lower cerebrospinal fluid thiamine levels than their controls (p less than 0.001 and p less than 0.04 respectively). These results, discussed in terms of the high degree of cerebellar atrophy on CT scans in OPCA v Friedreich's ataxia patients, seem to correlate with cerebellar thiamine turnover and content.