Clinical features and CACNA1A gene mutation in a family with episodic ataxia type 2 / 中南大学学报(医学版)

Episodic ataxia (EA) is a group of disorders characterized by recurrent spells of vertigo, truncal ataxia, and dysarthria. Episodic ataxia type 2 (EA2), the most common subtype of EA, is an autosomal dominant disease caused by mutation of the CACNA1A gene. EA2 has been rarely reported in the Chinese population. Here we present an EA2 family admitted to Xiangya Hospital in October 2018. The proband was a 22-year-old male who complained of recurrent spells of vertigo, slurred speech, and incoordination for 4 years. Brain magnetic resonance imaging (MRI) showed cerebellar atrophy. He had neuropsychological development disorder in childhood, and cognitive assessment in adulthood showed cognitive impairment. The proband's mother and grandmother had a similar history. Peripheral blood samples from the proband and family members were collected, and genomic DNA was isolated. Whole exome sequencing of the proband detected a heterozygous frameshift mutation c.2042_2043del (p.Q681Rfs*100) of CACNA1A gene. This mutation was verified in the proband and 2 family members using Sanger sequencing. One family member carrying this mutation was free of symptoms and signs, suggesting an incomplete penetrance of the mutation. We reported a variant c.2042_2043del of CACNA1A gene as the pathogenic mutation in a Chinese EA2 family for the first time. This case enriched the clinical spectrum of CACNA1A related EA2, and contributed to the understanding of clinical and genetic characteristics of EA2 to reduce misdiagnosis.

Clinical manifestation and genetic analysis of a child with early infantile epileptic encephalopathy 42 / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical phenotype and genetic characterization of a child with early infantile epileptic encephalopathy.@*METHODS@#The proband was subjected to history taking and was diagnosed based on his clinical manifestation, magnetic resonance imaging (MRI) and whole exome sequencing (WES). Sanger sequencing was carried out to determine the origin of pathogenic variant.@*RESULTS@#The proband unconsciously tilts his head to one side with squint, which revealed an abnormal discharge. MRI indicated suspicious abnormal signal shadow in the left posterior frontal cortex in addition with inflammation signs in the right maxillary sinus and ethmoid sinus. WES revealed that the proband has carried a heterozygous c.5789G>A variant in the CACNAIA gene. The result of Sanger sequencing was in keeping with that of WES. Neither of his parents has carried the same variant.@*CONCLUSION@#The heterozygous c.5789G>A variant of the CACNAIA gene probably underlay the early infantile epileptic encephalopathy 42 in the proband, which has a de novo origin.

Association between overweight and characteristics of young adult students: support for nursing care / Associação entre excesso de peso e características de adultos jovens escolares: subsídio ao cuidado de enfermagem / Asociación entre exceso de peso y características de adultos jóvenes escolares: contribución para el cuidado de enfermería

OBJECTIVE: to verify associations between overweight and the characteristics of young adult students to support nursing care. METHOD: case-control study conducted with young adults from public schools. The sample was composed of 441 participants (147 cases and 294 controls, with and without excess weight, respectively). Sociodemographic and clinical characteristics were collected together with exposure factors and anthropometrics. Multiple logistic regression was used. The study received Institutional Review Board approval. RESULTS: statistically significant association with overweight: non-Caucasian, having a partner; weight gain during adolescence, mother's excess weight, the use of obesogenic medication, augmented diastolic blood pressure, of abdominal circumference and waist/hip ratio. In addition to these, schooling and weight gain during childhood were also included in the multivariate analysis. After adjustment, the final model included: having a partner, weight gain during adolescence, augmented diastolic blood pressure and abdominal circumference. CONCLUSION: the analysis of predictor variables for excess weight among young adult students supports nurses in planning and developing educational practices aimed to prevent this clinical condition, which is a risk factor for other chronic comorbidities, such as cardiovascular diseases. .

OBJETIVO: verificar a associação entre excesso de peso e características de adultos jovens escolares, como subsídio ao cuidado de enfermagem. MÉTODO: estudo caso-controle, realizado com adultos jovens de escolas públicas. Amostra composta por 441 participantes (147 casos e 294 controles, com e sem excesso de peso, respectivamente). Coletaram-se informações sociodemográficas, clínicas, fatores de exposição e antropometria. Utilizou-se regressão logística múltipla. O estudo foi aprovado em comitê de ética. RESULTADOS: detectou-se associação estatística significativa com excesso de peso em: não brancos, ter companheiro(a), ganho ponderal na adolescência, excesso de peso materno, uso de fármacos obesogênicos, pressão arterial diastólica aumentada, circunferência abdominal e relação cintura quadril. Além destas, entraram na análise multivariada as variáveis escolaridade e ganho ponderal na infância. Após etapa de ajuste permaneceram no modelo final: estado civil com companheiro(a), ganho ponderal na adolescência, pressão arterial diastólica aumentada e circunferência abdominal aumentada. CONCLUSÃO: a análise das variáveis preditoras para o excesso de peso em adultos jovens escolares possibilita ao enfermeiro bases para elaboração e planejamento de práticas educativas que visem à prevenção desta condição clínica, visualizada como fator de risco para outras comorbidades de caráter crônico, como as doenças cardiovasculares. .

OBJETIVO: verificar la asociación entre exceso de peso y características de adultos jóvenes escolares como contribución para el cuidado de enfermería. MÉTODO: estudio de caso control realizado con adultos jóvenes de escuelas públicas. Muestra compuesta por 441 participantes (147 casos y 294 controles, con y sin exceso de peso, respectivamente). Se recolectaron características sociodemográficas, clínicas, factores de exposición y antropometría. Se utilizó la regresión logística múltiple. El estudio fue aprobado por comité de ética. RESULTADOS: se detectó asociación estadística significativa con exceso de peso: no blancos, tener compañero, aumento de peso en la adolescencia, exceso de peso materno, uso de medicamentos obesogénicos, presión arterial diastólica aumentada, circunferencia abdominal aumentada y relación cintura-cadera. Además de estas, entraron en el análisis multivariado las variables escolaridad y aumento de peso en la infancia. Después de la etapa de ajuste permanecieron en el modelo final: estado civil con compañero, aumento de peso en la adolescencia, presión arterial diastólica aumentada y circunferencia abdominal aumentada. CONCLUSIÓN: el análisis de las variables de predicción para el exceso de peso en adultos jóvenes escolares suministra al enfermero bases para la elaboración y planificación de prácticas educativas que objetiven la prevención de esta condición clínica, visualizada como factor de riesgo para otras enfermedades concomitantes de carácter crónico, como las enfermedades cardiovasculares. .

Association of single nucleotide polymorphisms of CACNA1A gene in migraine.

INTRODUCTION: Migraine is a chronic, neurovascular polygenic disease where genetic and environmental factors are involved in its etiology. Dysfunction of neuronal ion transportation can provide a model for predisposition for common forms of migraine. Mutations in genes encoding ion channels disturb the rhythmic function of exposed tissue that may also explain the episodic nature of migraine. Our aim was to study the single nucleotide polymorphisms of CACNA1A gene in migraine patients. MATERIALS AND METHODS: The subjects were the patients of migraine, in the age range of 18‑80 years, diagnosed by a Neurologist, as per the diagnostic criteria of International Headache Society (IHS) Classification 2004 after excluding other causes of headache by clinical examination and relevant investigations. The controls were the age and sex matched healthy persons from the same population excluding the relatives of patients. Only those patients and the controls, who voluntarily participated in the study, were taken and their blood samples were taken for the study. Deoxyribonucleic acid (DNA) extraction was performed according to the manufacturer’s protocol for Qiagen DNA extraction kits (Qiagen, Hilden, NRW, Germany). DNA content was quantified by spectrophotometric absorption (Nanodrop Spectrophotometer, BioLab, Scoresby, VIC, Australia). Polymerase chain reaction was performed using an iCycler Thermal Cycler (Bio‑Rad, Hercules, CA, USA). The polymorphic analysis of CACNA1A gene was carried out by two methods: Restriction fragment length polymorphism and sequencing. RESULTS: The study included a total of 25 patients of migraine, diagnosed on out‑patient department basis as per IHS Classification 2004 and compared with age and sex matched 25 healthy controls. Most of the patients 23 (92%) were below the age of 50 years. 20 of the patients (80%) were females and 5 (20%) were males. The polymorphic analysis of CACNA1A gene revealed the presence of only the wild form of the gene for the codon E993V in both case and control groups. CONCLUSION: In our study, we could not find any polymorphism of CACNA1A gene in the selected patients. Instead the wild type of genotype was found in both patients and controls. This negative result presented here, implies that if the CACNA1A gene is involved in typical migraine (with and without aura), its contribution is very modest and therefore difficult to discern. Nevertheless, there are other genes that could be considered potential candidates for typical migraine susceptibility for which further research is needed.

Whole-Genome Analysis in Korean Patients with Autoimmune Myasthenia Gravis

PURPOSE: The underlying cause of myasthenia gravis (MG) is unknown, although it likely involves a genetic component. However, no common genetic variants have been unequivocally linked to autoimmune MG. We sought to identify the genetic variants associated with an increased or decreased risk of developing MG in samples from a Korean Multicenter MG Cohort. MATERIALS AND METHODS: To determine new genetic targets related to autoimmune MG, a whole genome-based single nucleotide polymorphisms (SNP) analysis was conducted using an Axiom(TM) Genome-Wide ASI 1 Array, comprising 598375 SNPs and samples from 109 MG patients and 150 neurologically normal controls. RESULTS: In total, 641 SNPs from five case-control associations showed p-values of less than 10(-5). From regional analysis, we selected seven candidate genes (RYR3, CACNA1S, SLAMF1, SOX5, FHOD3, GABRB1, and SACS) for further analysis. CONCLUSION: The present study suggests that a few genetic polymorphisms, such as in RYR3, CACNA1S, and SLAMF1, might be related to autoimmune MG. Our findings also encourage further studies, particularly confirmatory studies with larger samples, to validate and analyze the association between these SNPs and autoimmune MG.

Long QT Syndrome: a Korean Single Center Study

The long QT syndrome (LQTS) is a rare hereditary disorder in which affected individuals have a possibility of ventricular tachyarrhythmia and sudden cardiac death. We investigated 62 LQTS (QTc > or = 0.47 sec) and 19 family members whose genetic study revealed mutation of LQT gene. In the proband group, the modes of presentation were ECG abnormality (38.7%), aborted cardiac arrest (24.2%), and syncope or seizure (19.4%). Median age of initial symptom development was 10.5 yr. Genetic studies were performed in 61; and mutations were found in 40 cases (KCNQ1 in 19, KCNH2 in 10, SCN5A in 7, KCNJ2 in 3, and CACNA1C in 1). In the family group, the penetrance of LQT gene mutation was 57.9%. QTc was longer as patients had the history of syncope (P = 0.001), ventricular tachycardia (P = 0.017) and aborted arrest (P = 0.010). QTc longer than 0.508 sec could be a cut-off value for major cardiac events (sensitivity 0.806, specificity 0.600). Beta-blocker was frequently applied for treatment and had significant effects on reducing QTc (P = 0.007). Implantable cardioverter defibrillators were applied in 6 patients. Congenital LQTS is a potentially lethal disease. It shows various genetic mutations with low penetrance in Korean patients.

Human umbilical artery smooth muscle exhibits a 2-APB-sensitive capacitative contractile response evoked by vasoactive substances and expresses mRNAs for STIM, Orai and TRPC channels

After depletion of intracellular Ca2+ stores the capacitative response triggers an extracellular Ca2+ influx through store-operated channels (SOCs) which refills these stores. Our objective was to explore if human umbilical artery smooth muscle presented this response and if it was involved in the mechanism of serotonin- and histamine-induced contractions. Intracellular Ca2+ depletion by a Ca2+-free extracellular solution followed by Ca2+ readdition produced a contraction in artery rings which was inhibited by the blocker of Orai and TRPC channels 2-aminoethoxydiphenyl borate (2-APB), suggesting a capacitative response. In presence of 2-APB the magnitude of a second paired contraction by serotonin or histamine was significantly less than a first one, likely because 2-APB inhibited store refilling by capacitative Ca2+ entry. 2-APB inhibition of sarcoplasmic reticulum Ca2+ release was excluded because this blocker did not affect serotonin force development in a Ca2+-free solution. The PCR technique showed the presence of mRNAs for STIM proteins (1 and 2), for Orai proteins (1, 2 and 3) and for TRPC channels (subtypes 1, 3, 4 and 6) in the smooth muscle of the human umbilical artery. Hence, this artery presents a capacitative contractile response triggered by stimulation with physiological vasoconstrictors and expresses mRNAs for proteins and channels previously identified as SOCs.

Familial Hemiplegic Migraine with Prolonged Coma and Cerebellar Atrophy: CACNA1A T666M Mutation in a Korean Family

We report the first Korean patient with familial hemiplegic migraine type 1, with clinical and multimodal imaging findings. A 43-yr-old man was admitted for right hemianopia and aphasia, followed by coma. MRI showed only cerebellar atrophy. CT angiography showed mild vasodilation of intracranial blood vessels and increased vascularity in the left hemisphere and perfusion-weighted imaging showed elevated cerebral blood flow. Gene analysis of the patient and his mother led to the identification of a heterozygous point mutation (1997C-->T, T666M) in exon 16 of the CACNA1A gene. Familial hemiplegic migraine should be considered in patients with episodic neurological dysfunction with cerebellar atrophy.

High Dose Vitamin D3 Attenuates the Hypocalciuric Effect of Thiazide in Hypercalciuric Rats

Thiazide is known to decrease urinary calcium excretion. We hypothesized that thiazide shows different hypocalciuric effects depending on the stimuli causing hypercalciuria. The hypocalciuric effect of hydrochlorothiazide (HCTZ) and the expression of transient receptor potential vanilloid 5 (TRPV5), calbindin-D(28K), and several sodium transporters were assessed in hypercalciuric rats induced by high calcium diet and vitamin D3. Urine calcium excretion and the expression of transporters were measured from 4 groups of Sprague-Dawley rats; control, HCTZ, high calcium-vitamin D, and high calcium-vitamin D with HCTZ groups. HCTZ decreased urinary calcium excretion by 51.4% in the HCTZ group and only 15% in the high calcium-vitamin D with HCTZ group. TRPV5 protein abundance was not changed by HCTZ in the high calcium-vitamin D with HCTZ group compared to the high calcium-vitamin D group. Protein abundance of NHE3, SGLT1, and NKCC2 decreased in the hypercalciuric rats, and only SGLT1 protein abundance was increased by HCTZ in the hypercalciuric rats. The hypocalciuric effect of HCTZ is attenuated in high calcium and vitamin D-induced hypercalciuric rats. This attenuation seems to have resulted from the lack of HCTZ's effect on protein abundance of TRPV5 in severe hypercalciuric condition induced by high calcium and vitamin D.

Protective Effects of Gabapentin on Allodynia and alpha2delta1-Subunit of Voltage-dependent Calcium Channel in Spinal Nerve-Ligated Rats

This study was designed to determine whether early gabapentin treatment has a protective analgesic effect on neuropathic pain and compared its effect to the late treatment in a rat neuropathic model, and as the potential mechanism of protective action, the alpha2delta1-subunit of the voltage-dependent calcium channel (alpha2delta1-subunit) was evaluated in both sides of the L5 dorsal root ganglia (DRG). Neuropathic pain was induced in male Sprague-Dawley rats by a surgical ligation of left L5 nerve. For the early treatment group, rats were injected with gabapentin (100 mg/kg) intraperitoneally 15 min prior to surgery and then every 24 hr during postoperative day (POD) 1-4. For the late treatment group, the same dose of gabapentin was injected every 24 hr during POD 8-12. For the control group, L5 nerve was ligated but no gabapentin was administered. In the early treatment group, the development of allodynia was delayed up to POD 10, whereas allodynia was developed on POD 2 in the control and the late treatment group (p<0.05). The alpha2delta1-subunit was up-regulated in all groups, however, there was no difference in the level of the alpha2delta1-subunit among the three groups. These results suggest that early treatment with gabapentin offers some protection against neuropathic pain but it is unlikely that this action is mediated through modulation of the alpha2delta1-subunit in DRG.

Spinocerebellar ataxia type 6 in Brazil / Ataxia espinocerebelar tipo 6 no Brasil

Spinocerebellar ataxia type 6 (SCA 6) is an autosomal dominant cerebellar ataxia caused by CAG repeat expansion in the SCA6 gene, a alpha 1A voltage-dependent calcium channel subunit gene on chromosome 19p13. SCA-6 is characterized predominantly by slowly progressive pure cerebellar ataxia with late onset. We report three index patients, with pure, late onset, cerebellar ataxia, belonging to three different Brazilian families, all of them with Japanese ancestry, from Hokkaido island of Japan.

Ataxia espinocerebelar tipo 6 (AEC6) é uma ataxia cerebelar autossômica dominante causada por uma expansão repetida do tripleto CAG no gene da AEC, que é uma sub-unidade do canal de cálcio voltagem-dependente alfa1A localizada no cromossomo 19p13. A AEC6 é caracterizada predominantemente por quadro de ataxia cerebelar pura, com início tardio, e evolução lentamente progressiva. Relatamos três pacientes índices, com ataxia cerebelar pura, de início tardio, pertencentes a três diferentes famílias brasileiras, todas com ancestrais japoneses, oriundas da ilha de Hokkaido.

Obesity induces upregulation of genes involved in myocardial Ca2+ handling

Obesity is a complex multifactorial disorder that is often associated with cardiovascular diseases. Research on experimental models has suggested that cardiac dysfunction in obesity might be related to alterations in myocardial intracellular calcium (Ca2+) handling. However, information about the expression of Ca2+-related genes that lead to this abnormality is scarce. We evaluated the effects of obesity induced by a high-fat diet in the expression of Ca2+-related genes, focusing the L-type Ca2+ channel (Cacna1c), sarcolemmal Na+/Ca2+ exchanger (NCX), sarcoplasmic reticulum Ca2+ ATPase (SERCA2a), ryanodine receptor (RyR2), and phospholamban (PLB) mRNA in rat myocardium. Male 30-day-old Wistar rats were fed a standard (control) or high-fat diet (obese) for 15 weeks. Obesity was defined as increased percent of body fat in carcass. The mRNA expression of Ca2+-related genes in the left ventricle was measured by RT-PCR. Compared with control rats, the obese rats had increased percent of body fat, area under the curve for glucose, and leptin and insulin plasma concentrations. Obesity also caused an increase in the levels of SERCA2a, RyR2 and PLB mRNA (P < 0.05) but did not modify the mRNA levels of Cacna1c and NCX. These findings show that obesity induced by high-fat diet causes cardiac upregulation of Ca2+ transport_related genes in the sarcoplasmic reticulum.

Coexistence of CACNA1A, ATP1A2, and KCNN3 gene mutation in migraine patients with human platelet polymorphism

To look for any possible coexistence of CACNA1A, ATP1A2, and KCNN3 gene mutations in migraine patients who had human platelet HPA-1a/1b polymorphism, which is also known as PlA1/A2 polymorphism. The study was carried out at the Neurology Clinic, Hospital University Sains Malaysia, Kelantan, Malaysia between April 2004 and March 2005. The DNA from 4 patients who had migraine with the HPA1a/1b polymorphism were analyzed by polymerase chain reaction using the allele specific oligonucleotide technique to detect the presence of CACNA1A, ATP1A2, and KCNN3 genotypes. We found that the CACNA1A gene mutation alone was present in only one patient who presented with classical migraine with aura. The gene mutations on ATP1A2 and KCNN3 were seen in none of our 4 cases with migraine. There is no coexistence between the platelet HPA-1a/1b polymorphism and the ATP1A2 and KCNN3 gene mutations, though one classical migraine patient with HPA-1a/1b polymorphism had the CACNA1A gene mutation. Larger studies are warranted to confirm these findings

The Genotype and Clinical Phenotype of Korean Patients with Familial Hypokalemic Periodic Paralysis

Familial hypokalemic periodic paralysis (HOPP) is a rare autosomal-dominant disease characterized by reversible attacks of muscle weakness occurring with episodic hypokalemia. Mutations in the skeletal muscle calcium (CACNA1S) and sodium channel (SCN4A) genes have been reported to be responsible for familial HOPP. Fifty-one HOPP patients from 20 Korean families were studied to determine the relative frequency of the known mutations and to specify the clinical features associated with the identified mutations. DNA analysis identified known mutations in 12 families: 9 (75%) were linked to the CACNA1S gene and 3 (25%) to the SCN4A gene. The Arg528His mutation in the CACNA1S gene was found to be predominant in these 12 families. Additionally, we have detected one novel silent exonic mutation (1950C>T) in the SCN4A gene. As for a SCN4A Arg669His mutation, incomplete penetrance in a woman was observed. Characteristic clinical features were observed both in patients with and without mutations. This study presents comprehensive data on the genotype and phenotype of Korean families with HOPP.

Mutation analysis of CACNA1A and ATP1A2 genes in Brazilian FHM families / Análise de mutações dos genes CACNA1A e ATP1A2 em famílias brasileiras afetadas por enxaqueca hemiplégica familial

Familial hemiplegic migraine (FHM) is a rare autosomal dominant form of migraine with aura. This disease has been associated with missense mutations in the CACNA1A and ATP1A2 genes. The aim of this study was to identify whether CACNA1A and ATP1A2 are or not related to Brazilian FHM. Here we screened four Brazilian FHM families (total of 26 individuals - 13 affected and 13 asymptomatic or normal) for mutations in both genes. We found an amino acid change in a member of family FHM-D (Arg2206Gly). However since this alteration is not present in all affected individuals and is present in one asymptomatic individual it should be considered a polymorphism. Further studies with additional families will be necessary to reveal the importance of both CACNA1A and ATP1A2 genes on the pathogeneses of FHM in Brazil and to test the third gene (SCN1A) in these FHM families.

A enxaqueca hemiplégica familial (EHF) é uma forma rara de enxaqueca com aura e apresenta herança autossômica dominante. Esta doença está associada com mutações do tipo missense nos genes CACNA1A e ATP1A2. O objetivo deste estudo foi identificar se os genes CACNA1A e ATP1A2 estão ou não relacionados com a enxaqueca hemiplégica familial em famílias brasileiras. Os genes citados acima foram analisados em quatro famílias brasileiras (total de 26 indivíduos - 13 afetados e 13 assintomáticos ou normais) e uma troca de aminoácido em um membro da família FHM-D (Arg2206Gly) foi observada. Porém, esta alteração não foi identificada em todos os indivíduos afetados e está presente em um indivíduo assintomático, devendo, portanto, ser considerada um polimorfismo. Estudos adicionais nas famílias já estudadas e em outras famílias brasileiras afetadas por enxaqueca hemiplégica familial serão necessários para esclarecer a importância dos genes CACNA1A e ATP1A2 na patogênese da EHF no Brasil, bem como para testar o terceiro gene (SCN1A) relacionado à EHF.

Calcium cycling proteins in heartfailure, cardiomyopathy and arrhythmias

A growing body of evidence, including studies using genetically engineered mouse models, has shown that Ca2+ cycling and Ca2+ -dependent signaling pathways play a pivotal role in cardiac hypertrophy and heart failure. In addition, recent studies identified that mutations of the genes encoding sarcoplasmic reticulum (SR) proteins cause human cardiomyopathies and lethal ventricular arrhythmias. The regulation of Ca2+ homeostasis via the SR proteins may have potential therapeutic value for heart diseases such as cardiomyopathy, heart failure and arrhythmias.

Episodic ataxia type 2: an uncommon inherited CNS channelopathies.

The author reports the first Thai patient with a rare inherited ataxic disorder characterized by intermittent episodes of ataxia, headache and vertigo. The patient was well between attacks despite persistent nystagmus on examination. Magnetic resonance imaging of the brain revealed cerebellar atrophy. All symptoms were ameliorated by acetazolamide therapy. This clinical syndrome was previously described as acetazolamide-responsive episodic ataxia which was subsequently shown to be associated with mutations in a alpha1A-subunit of P/Q type voltage-gated calcium channel gene, known as 'episodic ataxia type 2'. Clinical and molecular aspects of episodic ataxia type 2 were also reviewed.

Spinocerebellar Ataxia Type 6 and Episodic Ataxia Type 2 in a Korean Family

Spinocerebellar ataxia type 6 (SCA6), episodic ataxia type 2 (EA2) and familial hemiplegic migraine (FHM) have been known as allelic disorders, which are caused by the alteration of the alpha1A voltage-dependent calcium channel subunit. Expansions of the CAG repeat in the CACNA1A gene on the short arm of the chromosome 19 induce SCA6, and point mutations in the same gene are responsible for EA2 and FHM. In recent studies, both SCA6 and EA2 have been concurrently found in families with 26 CAG repeats without previously reported point mutations either in coding sequences or in intron-exon junctions. We describe a Korean family with CAG26 repeats in the CACNA1A gene. Some of the affected family members had progressive ataxia typical of SCA6 whereas others had episodic vertigo responsive to acetazolamide typical of EA2. Our family support that SCA6 and EA2 are allelic disorders with a high phenotypic variability.

Genomic structure of the regulatory region of the voltage-gated calcium channel alpha 1D

In excitable and endocrine organs, calcium influxes through the L-type voltage-gated calcium channel (VGCC) which is composed of four (alpha 1, alpha 2, beta, and gamma) subunits. Temporal and spatial expression of calcium channel activity is regulated by the transcription of alpha 1 subunit. To elucidate the genomic organization of the VGCC alpha 1D subunit gene, a genomic clone was isolated from the human genomic library and its sequence was analyzed. A 12 kb genomic clone contained the 5'-flanking regulatory region and first two exons was selected and the initiation site for alpha 1D mRNA synthesis was examined by primer extension analysis. The major initiation site was found at the -523 NT position in the translation initiation site. The TATA box could not be found above the transcription initiation site. The CAT vector construct containing the 2.5 kb upstream region had high CAT activity on transfection to NG108-15 and PC12 cells, which confers the neuronal expression of the alpha 1D gene.