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.

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.

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.

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.

A Case of Familial Hemiplegic Migraine / 대한소아신경학회지

Familial hemiplegic migraine(FHM) is an autosomal dominant subtype of migraine with aura, characterized by the occurrence of hemiplegia during the aura. Two subforms of FHM families exist; pure FHM in 80% and FHM families with cerebellar symptoms in 20%. Half of the known FHM families show genetic linkage to chromosome 19p13, and in these families FHM is caused by missense mutations in a neuronal P/Q type calcium channel alpha-1 subunit gene(CACNA1A gene). Linkages to 1q31 and 1q21-23 have also been established. Other families are linked neither to chromosome 19 nor 1. Clinical variabilities are partially associated with the various types of CACNA1A gene mutations. FHM is distinguished from more frequent migraine types by a clear, dominant inheritance pattern and the relative absense of other headache types. Further investigation of FHM will help to clarify the genetics of more common migraine. We describe a male patient with FHM with a brief review of the literature.