Assessing the relative incidence of mitochondrial DNA A3243G in migraine without aura with maternal inheritance

OBJECTIVE: To determine whether patients with migraine without aura with maternal "inheritance" are affected by a monosymptomatic form of the MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes) or carry the most common mitochondrial DNA (mtDNA) mutation associated with MELAS, namely the A3243G transition in the transfer RNA (tRNA)Leu(UUR) gene. BACKGROUND: The association between migraine and abnormal mitochondrial function has been suggested on clinical, biochemical, and neuroradiological grounds. Migraine attacks with vomiting and cerebral infarctions, most often in the posterior cerebral regions, which are reminiscent of complicated migraine, are typical features of MELAS. The observation that migrainous patients have affected mothers more often than affected fathers suggests a possible role for maternally transmitted genetic factors. METHODS: We studied 25 patients with migraine with aura whose mothers were also affected. A sensitive polymerase chain reaction restriction fragment length polymorphism analysis was used to detect mutated genomes. CONCLUSIONS: We failed to detect the MELAS mutation, but migraine may still be associated with point mutations of mtDNA other than A3243G or with as-yet-unidentified nuclear DNA factors related to mitochondrial function.     

Leukocyte mitochondrial DNA A to G polymorphism at 11084 is not a risk factor for Japanese migraineurs

Mitochondrial dysfunction has been reported in patients with migraine. We investigated leukocyte mitochondrial DNA 11084 A to G polymorphism in 166 Japanese migraineurs and 483 Japanese controls. The migraine group consisted of 43 patients suffering from migraine with aura (MWA) and 123 from migraine without aura (MOA). The frequency of the transition was 7.2% (12/166) in the migraine group and 7.3% (35/483) in the controls. The frequency of the transition was 4.7% in MWA and 8.1% in MOA. There was no significant difference among the groups (chi-square test). The mitochondrial DNA 11084 A to G transition was more common in Japanese subjects than reported in Caucasians; however, this polymorphism is not a genetic risk factor for migraine in Japanese patients.     

The epidemiology and mutation types of Leber’s hereditary optic neuropathy in Thailand

PurposeLeber’s hereditary optic neuropathy (LHON), the most common mitochondrial optic neuropathy, causes visual loss, especially in young adults. Due to the absence of epidemiological data in Southeast Asia, we aimed to determine Thai LHON patients’ characteristics (demographic data, mutation types, and prognoses) as the first study in this region.MethodsThis retrospective chart review enrolled all Thai LHON patients confirmed by three mitochondrial DNA mutations (G11778A, T14484C, and G3460A) between January 1997 and December 2016. Patients with more than one year of follow-up were included in a visual progression analysis. The Mann–Whitney U-test was applied to compare groups, and prognosis-associated factors were analysed with the generalized estimating equation.ResultsIn all, 229 patients were enrolled, with only nineteen females. Most mutations were of the G11778A type (91%), with T14484C accounting for the remainder. The age at onset of G11778A (21.9 years; interquartile range [IQR] 14.9, 33.5) was younger than that of T14484C (33.0 years; IQR 19.4, 37.5). Of 45 patients, the T14484C group demonstrated good vision recovery, whereas the G11778A group did not improve (difference in logMAR −0.7 and IQR −1.5, −0.2 versus logMAR 0.0 and IQR −0.3, 0.2, respectively; P value .001). The G11778A mutation, male, and older age were related to poor prognoses.ConclusionsThe leading mutation in Thai LHON patients is the G11778A missense, followed by T14484C, while G3460A was not detected. The vast majority of patients were young adult males. The G11778A mutation, older age, and male gender are associated with poor vision outcomes.

Key message

• The G11778A missense mutation is the most common among Thai LHON patients, followed by T14484C, while G3460A was not found. The G11778A mutation, older age, and male gender are associated with poor vision outcomes.

     

Detection and quantification of heteroplasmic mutant mitochondrial DNA by real-time amplification refractory mutation system quantitative PCR analysis: a single-step approach

BACKGROUND: The A3243G mitochondrial tRNA leu(UUR) point mutation causes mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome, the most common mitochondrial DNA (mtDNA) disorder, and is also found in patients with maternally inherited diabetes and deafness syndrome (MIDD). To correlate disease manifestation with mutation loads, it is necessary to measure the percentage of the A3243G mtDNA mutation. METHODS: To reliably quantify low proportions of the mutant mtDNA, we developed a real-time amplification refractory mutation system quantitative PCR (ARMS-qPCR) assay. We validated the method with experimental samples containing known proportions of mutant A3243G mtDNA generated by mixing known amounts of cloned plasmid DNA containing either the wild-type or the mutant sequences. RESULTS: A correlation coefficient of 0.9995 between the expected and observed values for the proportions of mutant A3243G in the experimental samples was found. Evaluation of a total of 36 patient DNA samples demonstrated consistent results between PCR-restriction fragment length polymorphism (RFLP) analysis and real-time ARMS-qPCR. However, the latter method was much more sensitive for detecting low percentages of mutant heteroplasmy. Three samples contained allele-specific oligonucleotide-detectable but RFLP-undetectable mutations. CONCLUSIONS: The real-time ARMS-qPCR method provides rapid, reliable, one-step quantitative detection of heteroplasmic mutant mtDNA.     

Migraine headache and mitochondrial DNA abnormality

Migraine headache is a heterogenous group of neurologic disorders with high prevalence in the general population and strong familial aggregation. Epidemiologic evidence for frequent maternal transmission has long suggested a role for an altered mitochondrial genetic background. This is supported by the observation of impaired energy metabolism and mitochondrial function in migraine patients as well as by the frequent association of migraine headache in MELAS. In the literature, some patients having migraine headache are reported to have mitochondrial DNA abnormalities, however, systematic screening studies have failed to demonstrate the clear relationship between migraine headache and mitochondrial DNA abnormalities. Migraine may be associated with mutations of nuclear genes which encode respiratory chain enzymes.     

多重连接探针扩增技术检测常见线粒体疾病

  目的  探讨多重连接探针扩增技术(multiplex ligation-dependent probe amplification, MLPA)用于常见线粒体疾病基因检测的可行性。  方法  收集2010年5月至2012年8月北京协和医院281例可疑线粒体异常病例, 包括神经科存在神经系统损伤的患者233例及眼科疑诊Leber遗传性视神经病变的患者48例, 运用MLPA法对常见线粒体疾病突变位点进行检测, 并使用线粒体基因序列测定方法进行验证。  结果  281例标本中共38例检测到线粒体基因突变, 总检出率为13.5%。眼科48例标本中, 3460G > A、11778G > A和14484T > C 3种突变共检测到19例, 检出率为39.6%;神经科233例标本中, 3243A > G、8344A > G、8993T > G和大片段缺失共检测到19例, 检出率为8.2%。除1例大片段缺失暂无PCR测序验证外, 其余MLPA结果均经序列测定验证为相符。  结论  MLPA法是一种可行的快速、准确、简便的基因诊断方法, 可作为筛查常见线粒体疾病的检测工具, 为临床诊断和治疗提供依据。     

Migraine with prolonged aphasic aura associated with a CACNA1A mutation: A case report and narrative review

Objective

To demonstrate that a known CACNA1A variant is associated with a phenotype of prolonged aphasic aura without hemiparesis.

Background

The usual differential diagnosis of prolonged aphasia without hemiparesis includes vascular disease, seizure, metabolic derangements, and migraine. Genetic mutations in the CACNA1A gene can lead to a myriad of phenotypes, including familial hemiplegic migraine (FHM) type 1, an autosomal dominant disorder characterized by an aura of unilateral, sometimes prolonged weakness. Though aphasia is a common feature of migraine aura, with or without hemiparesis, aphasia without hemiparesis has not been reported with CACNA1A mutations.

Methods

We report the case of a 51-year-old male who presented with a history of recurrent episodes of aphasia without hemiparesis lasting days to weeks. His headache was left sided and was heralded by what his family described as “confusion.” On examination, he had global aphasia without other focal findings. Family history revealed several relatives with a history of severe headaches with neurologic deficits including aphasia and/or weakness. Imaging revealed T2 hyperintensities in the left parietal/temporal/occipital regions on MRI scan with corresponding hyperperfusion on SPECT. Genetic testing revealed a missense mutation in the CACNA1A gene.

Conclusions

This case expands the phenotypic spectrum of the CACNA1A mutation and FHM to include prolonged aphasic aura without hemiparesis. Our patient's SPECT imaging demonstrated hyperperfusion in areas correlating with aura symptoms which can occur in prolonged aura.     

Rapid quantification of the heteroplasmy of mutant mitochondrial DNAs in Leber's hereditary optic neuropathy using the Invader technology

PURPOSE: To quantify the degree of heteroplasmy of a mitochondrial DNA (mtDNA) mutation in Leber's hereditary optic neuropathy (LHON) a biplex Invader assay was applied. METHODS: To determine the optimum condition for the Invader assay, mtDNAs were assayed in various amounts of total DNA in 1-4-h incubations at 63 degrees C. To evaluate the suitability of the Invader assay to detect the three mutations, G3460A, G11778A, and T14484C, 10 ng of DNAs from 224 patients with bilateral optic atrophy was assayed. To quantify mtDNA heteroplasmy, a standard curve of known mixture ratios of mutation against calculation by the Invader assay was constructed. Seventy-two of the 224 patients had one of the three mutations, which corresponded with the mutation detected earlier by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. The percentages of mutant mtDNAs were calculated by the Invader assay in five heteroplasmic families, including 30 individuals with the G11778A mutation. The results were compared with those calculated earlier by labeled polymerase chain reaction followed by single-strand conformation polymorphism (PCR-SSCP) analysis. RESULTS: In 1-8 ng of DNA, the fluorescence intensity increased near linearly during a 4-h assay. With more than 16 ng of DNA, the intensities were saturated even at the 2-h assay. A linear relationship was observed between the results obtained from separate mixtures and from the Invader assay analysis. Because two fluorescent intensities are not always the same, one of the two intensities was modified to adjust to that of the other. Complete concordance was observed between PCR-RFLP analysis and Invader assay genotyping for the 224 patients. Results of percentage of heteroplasmy in five LHON families obtained by the Invader assay were consistent with those by the PCR-SSCP analysis. CONCLUSIONS: Invader assay is a simple, rapid, and reliable method of genotyping mtDNA mutations as well as quantifying heteroplasmy simultaneously under optimum conditions.     

变性高效液相色谱技术在线粒体基因突变检测中的应用

目的以变性高效液相色谱(DHPLC)技术分析检测线粒体肌病患者线粒体基因突变,以明确诊断。方法收集4例临床诊断为线粒体肌病的患者,以50例健康体检者作为对照,提取患者肌肉组织及对照组外周血细胞DNA,用聚合酶链反应(po lym erase cha in reaction,PCR)扩增线粒体22个tRNA基因,利用变性高效液相色谱分析技术(denaturing h igh-per-form ance liqu id chrom atography,DHPLC)对PCR产物进行突变筛选,出现异常峰型的tRNA基因进行核苷酸序列测定,明确突变位点。结果4例线粒体肌病患者均检测出线粒体基因突变,突变分别为:例1tRNA-V a l基因发生A 1625G纯合突变,例2 tRNA-V a l基因发生A 1625G/A杂合突变,例3 RNA-A rg基因发生A 10411C/A杂合突变,例4 RNA-T rp基因发生T 5553C纯合突变。结论DHPLC能有效地用于线粒体基因突变的检测,该方法简便,结果稳定,可作为大样本筛查突变位点的一种便捷可靠手段。     

LHON患者线粒体基因组突变频谱分析

目的 探讨3个原发性点突变与LHON的关系，以了解我国LHON的发病特点，为LHON的快速诊断和产前咨询提供一个快速、经济适用的方法。方法 选取83例临床诊断为LHON患者，针对其mtDNA基因组3460、11778、14484位点设计引物进行PCR，并对PCR产物进行SSCP及DNA序列分析。同时选取25例正常健康成人作为对照。结果 所有83例被临床诊断为LHON先证者中，发现78例患者有线粒体基因组DNA的点突变，占舛．0％（78／83）。其中73例患者mtDNA存在．G11778A位点突变，占88．0％（73／83）；1例为G3460A位点突变，占1．2％（1／83）；4例为T11448C位点突变，占4．8％（4／83）。未发现有先证者携带两个以上上述突变位点。结论 我国LHON患者以mtDNA的G11778A位点突变为主，但也存在部分G3460A和T14484C位点患者家系；SSCP可以应用于对LHON的辅助诊断和遗传咨询。     

Migraine variants

The term "migrant variant" is not used in the headache classification of the International Headache Society (IHS), but it includes those forms of migraine that are not typical of migraine with or without aura. Headaches that do not quite fulfill all of the IHS criteria are termed "migrainous disorder." Migraine associated with auras arising from unusual sites includes basilar migraine, retinal migraine, and ophthalmoplegic migraine. Two of the chromosomal sites for hemiplegic migraine have been identified. Migraine aura may occur without headache and an aura may be prolonged. Migrainous infarct has occurred when the aura lasts more than 1 week or imaging studies are positive and other etiologies have been ruled out. If the migraine attack is prolonged beyond 3 days the term "status migrainousus" is applied.     

Abnormal blood lactate accumulation after exercise in patients with multiple mitochondrial DNA deletions and minor muscular symptoms

Study objectives: Muscle is one of the most commonly affected organs in mitochondrial disorders, and the symptoms are often exercise related. The cardiopulmonary exercise test with the determination of lactic acid formation could give supplementary information about the exercise‐induced metabolic stress and compensatory mechanisms used in these disorders. The aim of this study was to evaluate the exercise capacity and lactate kinetics related to exercise in subjects with two genetically characterized mitochondrial disorders (multiple mitochondrial DNA deletions with PEO, MELAS) compared with lactate kinetics in subjects with metabolic myopathy (McArdle's disease) and in the healthy controls. Design: The subjects were consecutive, co‐operative patients of Department of Neurology of Helsinki University Hospital. Molecular genetic analyses were used for group classification of the mitochondrial myopathy. Study subjects: The study groups consisted of 11 patients with multiple deletions (PEO) and five patients with a point mutation in the mitochondrial DNA (MELAS), four patients with a muscle phosphorylase enzyme deficiency (McArdle's disease) and 13 healthy controls. The clinical disease of the patients was relatively mild. Measurements and results: A graded exercise test with ventilatory gas analyses and venous blood lactic acid analyses was performed. The main finding was the prolonged accumulation of blood lactate after the exercise in the PEO and MELAS groups compared with the controls. An overcompensation in ventilation was found in the MELAS and PEO group. Conclusions: The blood lactate accumulation after exercise occurs in patients with multiple mitochondrial DNA deletions or MELAS even in patients with only mild exercise intolerance. Cardiopulmonary exercise can be used in the diagnostic process of patients with mitochondrial myopathies.     

Sporadic hemiplegic migraine

Sporadic hemiplegic migraine (SHM) is defined as migraine attacks associated with some degree of motor weakness/hemiparesis during the aura phase and where no first degree relative (parent, sibling or child) has identical attacks. The present review deals with recent scientific studies according to which: The SHM prevalence is estimated to be 0.005%; SHM patients have clinical symptoms identical to patients with familial hemiplegic migraine (FHM) and significantly different from patients with migraine with typical aura (typical MA); SHM affected had no increased risk of migraine without aura (MO), but a highly increased risk of typical MA compared to the general population; SHM patients only rarely have mutations in the FHM gene CACNA1A; SHM attacks in some cases can be treated with Verapamil. The reviewed data underlie the change in the International Classification of Headache Disorders 2nd edition where SHM became separated from migraine with typical aura or migraine with prolonged aura. All cases with motor weakness should be classified as either FHM or SHM.     

Migraine with aura after intracranial endovascular procedures

OBJECTIVE: To describe three cases of migraine (two with aura) after an intracranial endovascular procedure. Method.-Retrospective. RESULTS: One patient had an attack of migraine with prolonged aura after embolization of a dural arteriovenous fistula. Another patient had an attack of migraine with aura (and hemiparesis) after a diagnostic angiogram. The third patient already suffered from migraine with aura and had a migraine attack after embolization of an occipital arteriovenous malformation. A quadrantanopia persisted in this patient. Outcome of the other two patients was good. CONCLUSION: Intracranial endovascular procedures can induce migraine with aura. We could not identify the underlying pathophysiological mechanism, but mechanical, chemical, immunological, or hemodynamic factors could be involved.     

Real-time detection and quantification of mitochondrial mutations with oligonucleotide primers containing locked nucleic acid

BACKGROUND: The phenotypic expression of disorders caused by point mutations, deletions or depletions within the mitochondrial genome (mtDNA) is heterogeneous. This relates to the phenomena of heteroplasmy, tissue threshold as well as the distribution of mutant DNA among tissues. Hence, the diagnostics of these disorders demands highly specific, sensitive and quantitative methods. METHODS: We have developed an allele-specific quantitative real-time PCR method for the detection of two of the most prevalent disease causing mitochondrial mutations, m.3243A>G (MELAS) and m.8993T>G (NARP). Locked Nucleic Acid (LNA) modified primers were used to obtain high allele specificity. In order to monitor mtDNA depletion a real-time method for mtDNA/nuclear DNA copy number ratio determination was developed. RESULTS: Rapid and sensitive detection and quantification of MELAS and NARP mtDNA alleles were achieved. Heteroplasmy levels as low as 0.01% could be detected, and the mtDNA/nuclear DNA ratio could be determined. CONCLUSIONS: The present method that allows simultaneous determination of heteroplasmy levels and mtDNA/nuclear DNA copy number ratio, will provide a useful tool in molecular diagnostics and in future epidemiological studies of mitochondrial diseases.     

Triptans in the treatment of basilar migraine and migraine with prolonged aura

OBJECTIVE: To report on the use of triptans in migraine with prominent neurologic symptoms. BACKGROUND: As stated in their package inserts, the triptans are contraindicated in patients with basilar or familial hemiplegic migraine, and physicians are reluctant to prescribe these drugs to other patients with prominent or prolonged aura. METHODS: We evaluated 13 patients with basilar migraine, familial hemiplegic migraine, or migraine with prominent or prolonged aura who had received triptans. RESULTS: Excellent; no adverse events. CONCLUSION: The contraindication of triptans in basilar migraine should be reconsidered. Similarly, prominent or prolonged aura may not represent a reasonable contraindication to triptan therapy.     

Detection of common disease-causing mutations in mitochondrial DNA (mitochondrial encephalomyopathy, lactic acidosis with stroke-like episodes MTTL1 3243 A>G and myoclonic epilepsy associated with ragged-red fibers MTTK 8344A>G) by real-time polymerase chain reaction

The 3243A>G mutation in the MTTL1 (tRNA(Leu)) gene and the 8344A>G mutation in the MTTK (tRNA(Lys)) gene are the most common mutations found in mitochondrial encephalomyopathy, lactic acidosis with stroke-like episodes and myoclonic epilepsy associated with ragged-red fibers, respectively. These mitochondrial DNA mutations are usually detected by conventional polymerase chain reaction followed by restriction enzyme digestion and gel electrophoresis. We developed a LightCycler real-time polymerase chain reaction assay to detect these two mutations based on fluorescence resonance energy transfer technology and melting curve analysis. Primers and fluorescence-labeled hybridization probes were designed so that the sensor probe spans the mutation site. The observed melting temperatures differed in the mutant and wild-type DNA by 9 degrees C for the MTTL1 gene and 6 degrees C for the MTTK gene. This method correctly identified all 10 samples that were 3243A>G mutation-positive, all 4 samples that were 8344A>G mutation-positive, and all 30 samples that were negative for both mutations, as previously identified by traditional gel-based methods. This LightCycler assay is a rapid and reliable technique for molecular diagnosis of these mitochondrial gene mutations.     

Lack of interaction between a polymorphism in the dopamine D2 receptor gene and the clinical features of migraine

The purpose of this study was to evaluate whether a particular genotype of the dopamine D2 receptor (DRD2) gene would affect the clinical features of migraine. In a group of 118 migraineurs (55 migraine with aura and 63 migraine without aura patients), we tested the association of the biallelic C/T NcoI DRD2 polymorphism with several characteristics of the disease. Genotype and allele frequencies resulted similarly distributed in migraine with aura and migraine without aura patients (chi2 = 1.58, P = 0.45 and chi2 = 0.09, P = 0.77, respectively). The different DRD2 genotypes (C/C, C/T and T/T) had no significant effects on age at onset of migraine, presence of premonitory phenomena, frequency of headache attacks, associated symptoms, psychological features and quality of life of our migraine patients. The results of our study do not support a role for the DRD2 gene in modifying the clinical features of migraine.     

Calcitonin gene-related peptide does not cause migraine attacks in patients with familial hemiplegic migraine

(Headache 2011;51:544‐553) Background.— Calcitonin gene‐related peptide (CGRP) is a key molecule in migraine pathogenesis. Intravenous CGRP triggers migraine‐like attacks in patients with migraine with aura and without aura. In contrast, patients with familial hemiplegic migraine (FHM) with known mutations did not report more migraine‐like attacks compared to controls. Whether CGRP triggers migraine‐like attacks in FHM patients without known mutations is unknown. Objective.— In the present study we therefore examined the migraine‐inducing effect of CGRP in FHM patients without known mutations and healthy controls. Methods and design.— Eleven patients suffering from FHM without known mutations and 11 controls received an intravenous infusion of 1.5 µg/minute CGRP over 20 minutes. The study design was a balanced and controlled provocation study. Headache and other migraine symptoms were scored for 1 hour and self‐recorded hourly thereafter until 13‐hour postinfusion. Results.— We found no difference in the incidence of migraine‐like attacks between the 2 groups, with 9% (1 of 11) of patients and 0% (0 of 10) of controls reporting migraine‐like headache (P = 1.00). CGRP infusion did not induce aura symptoms in any of the participants. There was no difference in the incidence of CGRP‐induced delayed headaches between the groups (P = .18). Conclusion.— In contrast to patients suffering from migraine with aura and without aura, CGRP infusion did not induce more migraine‐like attacks in FHM patients without known mutations compared to controls. It seems that the majority of FHM patients with and without known mutation display no sensitivity to CGRP signaling compared to common types of migraine.