Abstract
Purpose
Malignant hyperthermia (MH) is an autosomal dominant pharmacogenetic disorder that is manifested on exposure of susceptible individuals to halogenated anesthetics or succinylcholine. Since MH is associated primarily with mutations in the ryanodine receptor type 1 (RYR1) gene, the purpose of this study was to determine the distribution and frequency of MH causative RyR1 mutations in the Canadian MH susceptible (MHS) population.
Methods
In this study, we screened a representative cohort of 36 unrelated Canadian MHS individuals for RYR1 mutations by sequencing complete RYR1 transcripts and selected regions of CACNA1S transcripts. We then analyzed the correlation between caffeine-halothane contracture test (CHCT) results and RYR1 genotypes within MH families.
Results
Eighty-six percent of patients had at least one RyR1 mutation (31 out of 36), five of which were unrelated individuals who were double-variant carriers. Fifteen of the 27 mutations identified in RYR1 were novel. Eight novel mutations, involving highly conserved amino acid residues, were predicted to be causal. Two of the mutations co-segregated with the MHS phenotype within two large independent families (a total of 79 individuals). Fourteen percent of MHS individuals (five out of 36) carried neither RYR1 nor known CACNA1S mutations.
Conclusions
The distribution and frequency of MH causative RyR1 mutations in the Canadian MHS population are close to those of European MHS populations. Novel mutations described in this study will contribute to the worldwide pool of MH-associated mutations in the RYR1 gene, ultimately increasing the value of MH genetic diagnostic testing.
Résumé
Objectif
L’hyperthermie maligne (HM) est une maladie pharmacogénétique héréditaire dominante autosomique qui se manifeste lors de l’exposition des personnes susceptibles à des anesthésiques halogénés ou à la succinylcholine. Étant donné que l’HM est principalement associée aux mutations au niveau du gène des récepteurs de ryanodine de type 1 (RYR1), l’objectif de cette étude était de déterminer la distribution et la fréquence des mutations RyR1 causant une HM chez la population canadienne susceptible à l’HM (SHM).
Méthode
Dans cette étude, nous avons examiné une cohorte représentative de 36 personnes canadiennes SHM sans liens familiaux pour identifier les mutations RYR1 en séquençant des transcrits complets de RYR1 et des régions choisies de transcrits de CACNA1S. Nous avons ensuite analysé la corrélation entre les résultats de l’étude de la contractilité de la cellule musculaire en présence de caféine et d’halothane (test CHCT) et les génotypes RYR1 au sein des familles d’HM.
Résultats
Quatre-vingt-six pour cent (31 sur 36) des patients ont manifesté au moins une mutation RyR1, dont cinq sans liens familiaux étaient porteurs de la double variante. Quinze des 27 mutations identifiées sur le RYR1 étaient nouvelles. Huit mutations nouvelles, y compris des acides aminés bien conservés, ont été anticipées comme étant causales. Deux des mutations se sont co-ségrégées avec le phénotype SHM dans deux vastes familles indépendantes (au total 79 personnes). Quatorze pour cent des personnes SHM (cinq sur les 36) n’étaient porteuses ni des mutations de RYR1 ni de mutations connues de CACNA1S.
Conclusion
La distribution et la fréquence de mutations de RyR1 causatives de HM dans la population canadienne SHM sont semblables à celles de populations européennes SHM. Les nouvelles mutations décrites dans cette étude s’ajouteront au fonds mondial de mutations associées à la HM dans le gène RYR1, ce qui contribuera à augmenter la valeur du dépistage diagnostique génétique de l’HM.
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Malignant hyperthermia (MH) is an autosomal dominant pharmacogenetic disorder triggered by exposure to volatile anesthetics and/or depolarizing muscle relaxants.1,2 MH manifests as a potentially lethal hypermetabolic crisis caused by a rapid and uncontrolled increase in myoplasmic Ca2+ in skeletal muscle cells.3,4 Since MH was first recognized as an inherited condition in 1960,5 at least six potential genetic loci for MH susceptibility have been proposed.6 However, MH-associated mutations have been found in only two genes, the RYR1 gene (MIM 180 901) on chromosome 19q13.1 encoding the calcium release channel of the sarcoplasmic reticulum, also known as the ryanodine receptor type 1 (RyR1), and the CACNA1S gene (MIM 114 208) on chromosome 1q32 encoding the α1-subunit of the voltage-gated calcium channel, also known as the dihydropyridine receptor. Both RyR1 and dihydropyridine receptors play key roles in the processes of excitation–contraction coupling and maintenance of Ca2+ homeostasis in skeletal muscle cells.7 Malignant hyperthermia genetic research has shown that RYR1 is the major causal gene for MH as well as for a congenital myopathy, central core disease (CCD).3,6 Malignant hyperthermia-associated RYR1 mutations have been found in 60% to 86% of MH families with diverse ethnicity,8–11 and their distribution and frequency have been shown to be population-specific.6 Recent improvements in molecular genetics methods have facilitated genetic analysis of the entire coding region of RYR1, which is ~159,000 nucleotides long and contains 106 exons that are spliced into a 15 kb RYR1 mRNA transcript.12 The number of MH- and CCD-associated RYR1 mutations continues to grow and, in our current estimate, includes some 300 mutations.13 For the second causal gene, CACNA1S, only three MH-associated mutations have been reported.14-18
Genetic testing based on advances in MH genetic research is playing an increasingly important role in MH diagnostics. It has proven to be especially useful in early diagnosis of children and patients who cannot undergo the caffeine-halothane contracture test (CHCT) for MH susceptibility because CHCT requires an invasive muscle biopsy.19,20 Nevertheless, genetic testing for MH has low sensitivity because the European Malignant Hyperthermia Group (www.emhg.org) and the Malignant Hyperthermia Association of the United States (www.mhaus.org) currently accept only 30 well-characterized mutations as being MH causative. Development of genetic testing with high sensitivity depends on the establishment of an exhaustive collection of MH-causative mutations; hence, the continuing search for new mutations in diverse populations as well as validation of their MH causality. The objective of our study was to identify the spectrum of MH-associated mutations in the Canadian MH susceptible (MHS) population and to establish their frequency and distribution.
Methods
Patients
For this observational study, Research Ethics Board approval was obtained from each of the Universities of Toronto and Ottawa. All of the MHS patients who presented to the Malignant Hyperthermia Investigation Unit at the Department of Anesthesia, Toronto General Hospital, Toronto, Canada from 2003 to 2008 were considered to be potential subjects of the study. The following inclusion criteria were used to maximize the likelihood that each individual selected was MHS: a positive CHCT21 in individuals with a family history of MH; abnormally high levels of serum creatine kinase and a family history of MH;22,23 a Clinical Grading Scale Score24 of >35 if an individual had experienced an MH episode. Of 53 individuals approached, 36 (each representing an unrelated Canadian MH family) gave written informed consent for participation in our research study on the molecular genetics of malignant hyperthermia and were included in the study. Two of the 36 individuals were referred to us from the University of Ottawa. To analyze phenotype–genotype correlations, relatives of the chosen individuals (a total of 116 individuals) subsequently consented to enrol in the study (Table 1).
Transcript sequencing
Patient blood and/or muscle samples were collected, and nucleic acids were isolated according to published procedures.25,26 Ribonucleic acid (RNA) isolation from blood leukocytes as well as complementary DNA (cDNA) synthesis and polymerase chain reaction (PCR) amplification of the RYR1 transcript were performed as described previously,27 with minor modifications. Sequencing reactions were run at the DNA Sequencing and Synthesis Facility of The Centre for Applied Genomics, Toronto, Canada.
DNA sequence analysis and genetic analysis of amino acid substitutions identified
Raw sequence data analysis (contig building and sequence comparison to the reference RYR1 sequences GenBank accessions NM_000540.2 and NC_000019) was carried out using Sequencher 4.7 (Gene Codes, Ann Arbor, MA, USA).
Each missense DNA sequence variant identified by RYR1 transcript sequencing was confirmed by analysis of the patient’s genomic DNA. A mutation-specific genotyping assay was designed for each novel mutation, and a panel of 200-300 normal control chromosomes was screened to assess the frequency of the mutation in the general population.
Genetic characterization of the novel mutations was performed using various bioinformatics tools via HTTP interface, primarily on the Expasy Web site (www.expasy.ch, Switzerland), the site of the European Institute of Bioinformatics (www.ebi.ac.uk, UK), and the site of the National Centre for Biotechnology Information (www.ncbi.nlm.nih.gov, USA). Additional bioinformatic analysis of each novel mutation in terms of its possible effect on RyR1 protein function was carried out using three bioinformatic computer programs: PolyPhen-228 (http://genetics.bwh.harvard.edu/pph2/); SIFT29 (http://sift.jcvi.org/); and PMut30 (http://mmb2.pcb.ub.es:8080/PMut/). These programs use bioinformatic data, such as protein sequence homology, structural information, or annotations of protein functional domains, as input, and they predict the probability that an amino acid substitution will be either neutral or damaging to the protein function. The three programs we selected have been tested31 on human disease-associated mutation datasets and on datasets of neutral amino acid substitutions and have produced predictions with false-positive error rates from 9% to 20% and false negative error rates from 21% to 31%.
Results
RyR1 mutations in the Canadian MHS population
By sequencing entire RYR1 transcripts, we identified 28 non-synonymous nucleotide sequence changes that would result in 27 different amino acid changes (mutations) in 31 out of 36 MHS individuals. In this study of RYR1, our mutation detection rate was 86% (Table 1). Five unrelated individuals in this cohort were double-variant carriers.
Of the 27 RyR1 mutations identified, seven are known MH-causative mutations, five have been reported previously in association with MH, and 15 are novel. All except one of the novel mutations represent single nucleotide changes and all were heterozygous. None of the novel mutations was found in at least 200 control chromosomes.
Previously reported RyR1 mutations
Fifteen of 31 Canadian MHS individuals with identified mutations (48.4%) carried known MH causative RyR1 mutations (www.emhg.org): p.Arg163Cys (n = 1), p.Gly341Arg (n = 3), p.Arg614Cys (n = 4), p.Arg2163His (n = 2), p.Val2168Met (n = 1), Gly2434Arg (n = 4), p.R2454H (n = 1). One patient was a carrier of two causative mutations, p.Gly341Arg and p.Arg614Cys, that were transmitted to both of the patient’s children, indicating that the mutations might be located on the same allele.
Five other unrelated patients carried recurrent mutations not yet proven to be causal of MH, p.Arg1667Cys,32 p.Ala2200Val,8 p.Arg2336His,10 p.Val4849Ile,33 p.Gly4935Ser.34 One individual from this group carried a novel mutation, p.Glu209Lys, in combination with a recurrent mutation, p.Arg2336His.
Novel RYR1 mutations
We identified 15 novel RyR1 mutations in 12 patients. Three patients carried two novel RyR1 mutations each: a patient from family C-16 (p.Cys64Arg/p.Ala3421Val); a patient from family C-20 (p.Arg2126Gln/p.Gly3938Asp); and a patient from family C-25 (p.Ala4185Thr/p.Val4842Met). In addition, a patient from family C-26 carried an RYR1 sequence variant involving two adjacent nucleotides, c.14422T>A c.14423T>A (Fig. 1). The allelic status of these changes was resolved by real-time PCR using a set of allele-specific primers (data not shown). Both mutations were located on the same allele, so that the amino acid change is predicted to be p.Phe4808Asn. It is of interest that the mutation, c.14422T>A, resulting in the amino acid change, p.Phe4808Ile, has been reported previously in association with MH.35
RYR1 polymorphisms
Three previously reported RyR1 polymorphisms, p.Pro1787Leu (rs34934920), p.Gly2060Cys (rs35364374), and p.Glu3583Gln (rs55876273) (NCBI dbSNP, www.ncbi.nlm.nih.gov/projects/SNP/), were found to be present either alone (p.Glu3583Gln, n = 1) or together with other mutations in four unrelated patients. In addition, four novel and 26 previously reported silent polymorphisms were detected.
Splicing variants
In line with previous reports,6,10 RYR1 transcripts with skipped exons 70 and 83 were present in most of our samples. In addition, skipping of exons 9, 31, 66, and 94 was observed in blood RNA. In all cases, missing exons, together with their adjacent intronic regions, were re-sequenced directly from genomic DNA samples to confirm that their absence was not due to aberrant splicing that might have been caused by a contiguous mutation.
Patients without mutations
In five of our MHS patients from families C-32 to C-36 in Table 1, we found no RYR1 mutations. Screening of the CACNA1S gene in these patients for the presence of three known MH causative mutations, p.Arg174Trp, p.Arg1086His, and Arg1086Ser,14–18 also gave negative results.
Protein localization and predicted effect of identified RyR1 mutations
All except one mutation involved amino acid residues that were positioned within RyR1 regions of high evolutionary conservation; furthermore, 13 mutations were mapped within known RyR1 functional domains. According to the results of bioinformatic analysis, the recurrent and novel mutations could be divided into three groups: probably causative, possibly causative, and benign (Table 2).
Phenotype–genotype analysis
Two unrelated families, C-27 and C-18, were available for segregation analysis (Fig. 2). Family C-27 is a large three-generation French–Canadian family in which three fatal MH episodes have occurred, and 38 out of 76 relatives have been diagnosed as MHS from 1993 to 2008. A novel p.Val4847Leu mutation was detected in an MHS individual from a family branch with two fatal MH episodes; the mutation segregated well with the MHS phenotype within this family branch (Fig. 2A). However, 26 MHS individuals from other branches of the family did not carry the p.Val4847Leu mutation. Of these, 21 had a positive contracture test with halothane but were negative for caffeine-induced contracture. Thus, another undetected RYR1 mutation may exist in these branches of the family. In family C-18 (Fig. 2B), the p.Arg2336His mutation was identified in combination with a novel p.Glu209Lys mutation in a proband diagnosed as MHS by CHCT. Genetic screening of the family showed that both mutations were located on the same allele and that they segregated well with the MHS phenotype. However, one discordant individual, the maternal aunt of the proband, was diagnosed as MHS but did not carry either of the two mutations.
In the remaining 29 families, the absence of CHCT data for additional family members prevented segregation analysis. Analysis of families C-19, C-22, C-26, and C-30 showed that four mutations identified in the MHS individuals (p.Arg1667Cys, p.Ser2843Pro, p.Phe4808Asn, p.Gly4935Ser, correspondingly) were all absent in relatives with negative CHCT results (MHN). In contrast, mutations p.Ala140Thr and p.Gly4104Arg, identified in probands from families C-17 and C-24, were also found in an MHN relative in each case. Moreover, the mutation p.Ile4928Val, identified in the proband from family C-29, was absent from his MHS relative.
Discussion
In this study aimed at the identification of MH-associated RYR1 mutations in the Canadian MHS population, seven known MH causal RyR1 mutations and 20 potentially causal mutations, including 15 novel mutations, were identified (a mutation detection rate of 86%) (Table 1). None of the MHS individuals included in the study showed any myopathic features, including individuals who carried two MH causative mutations each. This observation is consistent with a published report for clinically asymptomatic MHS patients who were homozygous or compound heterozygous for MH causative mutations15 and with the conclusions of early exhaustive studies showing the absence of morphological abnormalities in MH muscle.13
The high RYR1 mutation detection rate observed in this study can be explained by the stringent selection criteria for enrolment into the study and by the mutation screening strategy, which consisted of sequence analysis of complete RYR1 transcripts. Comparable detection rates (70% to 86%) have been reported recently for other MHS populations8–10 where genetic screening included the entire coding sequence of the gene. On the other hand, if only established MH causative mutations from the EMHG database (www.emhg.org) were considered, then the mutation detection rates or the diagnostic sensitivity of the genetic testing would be 42% in this study and from 28% to 33% in other studies.8–10 This does not compare favourably with a reported sensitivity of 97% to 99% for CHCT and in vitro contracture test (IVCT), respectively.36,37 Published data indicate that the frequency of MH-causative RyR1 mutations is population-specific, with only a few mutations accounting for the majority of MH cases in some populations.6 By comparison, we found that p.Arg614Cys, p.Gly341Arg, and p.Gly2434Arg are the most frequent mutations in the Canadian MHS population, accounting for almost 35% of mutation-positive families. This outcome is not unexpected since these mutations are common in Germany, France, and the UK (Table 3), and individuals of Western European origin comprised >60% of our study group. The result also reflects the ethnic structure of the Canadian population, which consists of up to 75% of individuals with a genetic heritage from England, Scotland, Ireland, France, and Germany (data from the Canada Census 2006). A high proportion of mutations with unknown causal potential (55.6%) observed in this study is comparable with that found in other published studies (40% to 78%).8–10 Although we have not yet performed functional testing of the novel RyR1 mutations, genetic analysis allowed evaluation of their potential as probably causative, possibly causative, and benign (Table 2). The group of probably causative mutations contains eight mutations: p.Cys64Arg, p.Arg2336His, p.Ser2843Pro, p.Trp3284Arg, p.Gly3938Asp, p.Phe4808Asn, p.Val4847Leu, and p.Gly4935Ser. These mutations affected evolutionarily highly conserved amino residues within well-conserved protein regions and were predicted with high reliability to be deleterious. The MH causative nature of two mutations from this group, p.Arg2336His and p.Val4847Leu, is supported by their co-segregation with the MHS phenotype in families C-18 and C-27, respectively. In addition, p.Arg2336His found in cis with a novel mutation, p.Glu209Lys, in a Canadian MHS proband was recently reported to be causal for MH in several Swiss families.10 The p.Val4847Leu that co-segregated well with an MHS phenotype within a large French–Canadian family, C-27, is positioned within the putative transmembrane segment and maps to the HS3b “mutation hot spot’’ region in RyR1.13,38 At least three other closely spaced MH/CCD mutations are located within the same transmembrane segment33,39,40 (Fig. 3). The mutations p.Ser2843Pro and p.Gly4935Ser deserve special consideration because they affect critical amino acid residues. Ser2843, identified in an MH proband (family C-22) with positive CHCT results, has the potential of being involved in the regulation of Ca2+ release channel function through serine phosphorylation.41,42 The second mutation, p.Gly4935Ser, identified in an MHS first-degree relative of the proband who had a fatal MH crisis, maps to the centre of the last transmembrane segment (amino acids 4918-4948) within the pore-forming region of RyR138and a mutation hot spot, HS3b, where disease-associated mutations occur at a rate of about one in every three amino acids.13 Furthermore, the p.Gly4935Ser was recently reported to be associated with MH in a large Brazilian pedigree.34 Mutations involving adjacent amino acid residues, p.Ile4938Met and p.Asp4939Glu, have also been associated with MH.43 The second group is comprised of mutations with yet unclear causal potential. Two of them, p.Ala2200Val and p.Val4842Met, each found in an MHS first-degree relative of a proband in their families, might be considered as possibly causative. The p.Ala2200Val lies within HS2a and maps within a region in RyR1 (amino acids 1924-2446) shown to be essential for E–C coupling in skeletal muscle.44 This mutation was linked to MH in two unrelated families from two different populations.6 Moreover, several other MH-associated mutations are located in the same region.45–47 The second mutation, p.Val4842Met, maps to the last transmembrane segment that forms a part of the Ca2+ channel pore of RyR1. It was recently found in two unrelated patients with recessive forms of CCD.48 In contrast, another mutation from this group, p.Ala140Thr, is most likely a rare benign polymorphism similar to the only mutation from the third group, p.Ala4185Thr, which was predicted to be neutral by bioinformatic programs. This prediction is supported by the results of segregation analysis; p.Ala140Thr was identified in a second-degree relative of a proband, whereas the proband and another MHS relative did not carry this mutation. The occurrence of benign RYR1 mutations highlights the point that knowledge of the entire spectrum of RYR1 variants occurring in both MHS and MHN individuals would facilitate the identification of mutations that are associated with the MHS phenotype. Unfortunately, it is not yet feasible to screen MHN individuals or the general population for RYR1 mutations.
Despite being labelled as MHS on the basis of their CHCT results and representing families with a clear history of MH, five individuals in this study (14%) carried neither mutations in RYR1 nor known mutations in CACNA1S. The absence of RYR1 mutations in MHS individuals, together with the presence of discordant cases in families C-18 and C-27 and other MH families worldwide,8,10 may be explained by the sensitivity and specificity of the CHCT, which identifies both false negatives and false positives at a low rate.36,37,49 Another reason might be the possible involvement of as yet unrecognized genetic and environmental factors in the MHS phenotype. For example, mutations in calsequestrin (CASQ1) might be expected to cause MH, since a mouse CASQ1 knockout line displays MHS symptoms.50 The complex genetic nature of MH, revealed through the existence of discordant cases, is the reason why negative genetic results based on RYR1 screening alone cannot rule out a diagnosis of MH susceptibility.
In conclusion, this study has provided insight into the spectrum of MH-associated RYR1 mutations in the Canadian MHS population by showing that it is close to that of certain European MHS populations. Genetic analysis shows that eight novel mutations, p.Cys64Arg, p.Arg2336His, p.Ser2843Pro, p.Trp3284Arg, p.Gly3938Asp, p.Phe4808Asn, p.Val4847Leu, and p.Gly4935Ser, are good candidates for MH causative mutations. However, additional segregation data as well as functional characterization of the novel mutations are still needed to establish their role in MH. Another limitation of this study is that it included only about 20% of MH families registered in the Malignant Hyperthermia Investigation Unit database. Further genetic screening of the remaining MH families will help identify the full spectrum of MH-associated mutations in Canada. Our data corroborate some of the results reported recently in other MH populations and emphasize the fact that the rate of discovery of novel mutations remains high. This study will contribute to the worldwide pool of MH-associated mutations, ultimately increasing the value of MH genetic diagnostic testing.
References
Britt BA, Kalow W. Malignant hyperthermia: aetiology unknown. Can Anaesth Soc J 1970; 17: 316-30.
Rosenberg H, Davis M, James D, Pollock N, Stowell K. Malignant hyperthermia. Orphanet J Rare Dis 2007; 2: 21.
MacLennan DH, Phillips MS. Malignant hyperthermia. Science 1992; 256: 789-94.
Mickelson JR, Ross JA, Hyslop RJ, Gallant EM, Louis CF. Skeletal muscle sarcolemma in malignant hyperthermia: evidence for a defect in calcium regulation. Biochim Biophys Acta 1987; 897: 364-76.
Denborough MA, Forster JF, Lovell RR, Maplestone PA, Villiers JD. Anaesthetic deaths in a family. Br J Anaesth 1962; 34: 395-6.
Robinson R, Carpenter D, Shaw MA, Halsall J, Hopkins P. Mutations in RYR1 in malignant hyperthermia and central core disease. Hum Mutat 2006; 27: 977-89.
Melzer W, Herrmann-Frank A, Luttgau HC. The role of Ca2+ ions in excitation–contraction coupling of skeletal muscle fibres. Biochim Biophys Acta 1995; 1241: 59-116.
Sambuughin N, Holley H, Muldoon S, et al. Screening of the entire ryanodine receptor type 1 coding region for sequence variants associated with malignant hyperthermia susceptibility in the North American population. Anesthesiology 2005; 102: 515-21.
Galli L, Orrico A, Lorenzini S, et al. Frequency, localization of mutations in the 106 exons of the RYR1 gene in 50 individuals with malignant hyperthermia. Hum Mutat 2006; 27: 830.
Levano S, Vukcevic M, Singer M, et al. Increasing the number of diagnostic mutations in malignant hyperthermia. Hum Mutat 2009; 30: 590-8.
Tammaro A, Di Martino A, Bracco A, et al. Novel missense mutations and unexpected multiple changes of RYR1 gene in 75 malignant hyperthermia families. Clin Genet 2010. DOI:10.1111/j.1399-0004.2010.01493.x.
Phillips MS, Fujii J, Khanna VK, et al. The structural organization of the human skeletal muscle ryanodine receptor (RYR1) gene. Genomics 1996; 34: 24-41.
MacLennan DH, Zvaritch E. Mechanistic models for muscle diseases and disorders originating in the sarcoplasmic reticulum. Biochim Biophys Acta 2010. DOI:10.1016/j.bbamcr.2010.11.009.
Monnier N, Procaccio V, Stieglitz P, Lunardi J. Malignant-hyperthermia susceptibility is associated with a mutation of the alpha 1-subunit of the human dihydropyridine-sensitive L-type voltage-dependent calcium-channel receptor in skeletal muscle. Am J Hum Genet 1997; 60: 1316-25.
Monnier N, Krivosic-Horber R, Payen JF, et al. Presence of two different genetic traits in malignant hyperthermia families: implication for genetic analysis, diagnosis, and incidence of malignant hyperthermia susceptibility. Anesthesiology 2002; 97: 1067-74.
Stewart SL, Hogan K, Rosenberg H, Fletcher JE. Identification of the Arg1086His mutation in the alpha subunit of the voltage-dependent calcium channel (CACNA1S) in a North American family with malignant hyperthermia. Clin Genet 2001; 59: 178-84.
Toppin PJ, Chandy TT, Ghanekar A, Kraeva N, Beattie WS, Riazi S. A report of fulminant malignant hyperthermia in a patient with a novel mutation of the CACNA1S gene. Can J Anesth 2010; 57: 689-93.
Carpenter D, Ringrose C, Leo V, et al. The role of CACNA1S in predisposition to malignant hyperthermia. BMC Med Genet 2009; 10: 104.
Urwyler A, Deufel T, McCarthy T, West S, European Malignant Hyperthermia Group. Guidelines for molecular genetic detection of susceptibility to malignant hyperthermia. Br J Anaesth 2001; 86: 283-7.
Gillies RL, Bjorksten AR, Davis M, Du Sart D. Identification of genetic mutations in Australian malignant hyperthermia families using sequencing of RYR1 hotspots. Anaesth Intensive Care 2008; 36: 391-403.
Larach MG. Standardization of the caffeine halothane muscle contracture test. North American Malignant Hyperthermia Group. Anesth Analg 1989; 69: 511-5.
Britt BA, Endrenyi L, Peters PL, Kwong FH, Kadijevic L. Screening of malignant hyperthermia susceptible families by creatine phosphokinase measurement and other clinical investigations. Can Anaesth Soc J 1976; 23: 263-84.
Carpenter D, Robinson RL, Quinnell RJ, et al. Genetic variation in RYR1 and malignant hyperthermia phenotypes. Br J Anaesth 2009; 103: 538-48.
Larach MG, Localio AR, Allen GC, et al. A clinical grading scale to predict malignant hyperthermia susceptibility. Anesthesiology 1994; 80: 771-9.
Chomczynski P, Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem 1987; 162: 156-9.
Miller SA, Dykes DD, Polesky HF. A simple salting out procedure for extracting DNA from human nucleated cells. Nucleic Acids Res 1988; 16: 1215.
Kraev N, Loke JC, Kraev A, MacLennan DH. Protocol for the sequence analysis of ryanodine receptor subtype 1 gene transcripts from human leukocytes. Anesthesiology 2003; 99: 289-96.
Adzhubei IA, Schmidt S, Peshkin L, et al. A method and server for predicting damaging missense mutations. Nat Methods 2010; 7: 248-9.
Kumar P, Henikoff S, Ng PC. Predicting the effects of coding non-synonymous variants on protein function using the SIFT algorithm. Nat Protoc 2009; 4: 1073-81.
Ferrer-Costa C, Orozco M, de la Cruz X. Sequence-based prediction of pathological mutations. Proteins 2004; 57: 811-9.
Ng PC, Henikoff S. Predicting the effects of amino acid substitutions on protein function. Annu Rev Genomics Hum Genet 2006; 7: 61-80.
Ibarra MC, Wu S, Murayama K, et al. Malignant hyperthermia in Japan: mutation screening of the entire ryanodine receptor type 1 gene coding region by direct sequencing. Anesthesiology 2006; 104: 1146-54.
Jungbluth H, Muller CR, Halliger-Keller B, et al. Autosomal recessive inheritance of RYR1 mutations in a congenital myopathy with cores. Neurology 2002; 59: 284-7.
Matos AR, Sambuughin N, Rumjanek FD, et al. Multigenerational Brazilian family with malignant hyperthermia and a novel mutation in the RYR1 gene. Braz J Med Biol Res 2009; 42: 1218-24.
Davis MR, Haan E, Jungbluth H, et al. Principal mutation hotspot for central core disease and related myopathies in the C-terminal transmembrane region of the RYR1 gene. Neuromuscul Disord 2003; 13: 151-7.
Allen GC, Larach MG, Kunselman AR. The sensitivity and specificity of the caffeine-halothane contracture test: a report from the North American Malignant Hyperthermia Registry. The North American Malignant Hyperthermia Registry of MHAUS. Anesthesiology 1998; 88: 579-88.
Ording H, Brancadoro V, Cozzolino S, et al. In vitro contracture test for diagnosis of malignant hyperthermia following the protocol of the European MH Group: results of testing patients surviving fulminant MH and unrelated low-risk subjects. The European Malignant Hyperthermia Group. Acta Anaesthesiol Scand 1997; 41: 955-66.
Du GG, Sandhu B, Khanna VK, Guo XH, MacLennan DH. Topology of the Ca2+ release channel of skeletal muscle sarcoplasmic reticulum (RyR1). Proc Natl Acad Sci USA 2002; 99: 16725-30.
Oyamada H, Oguchi K, Saitoh N, et al. Novel mutations in C-terminal channel region of the ryanodine receptor in malignant hyperthermia patients. Jpn J Pharmacol 2002; 88: 159-66.
Monnier N, Kozak-Ribbens G, Krivosic-Horber R, et al. Correlations between genotype and pharmacological, histological, functional, and clinical phenotypes in malignant hyperthermia susceptibility. Hum Mutat 2005; 26: 413-25.
Stange M, Xu L, Balshaw D, Yamaguchi N, Meissner G. Characterization of recombinant skeletal muscle (Ser-2843) and cardiac muscle (Ser-2809) ryanodine receptor phosphorylation mutants. J Biol Chem 2003; 278: 51693-702.
Reiken S, Lacampagne A, Zhou H, et al. PKA phosphorylation activates the calcium release channel (ryanodine receptor) in skeletal muscle: defective regulation in heart failure. J Cell Biol 2003; 160: 919-28.
Shepherd S, Ellis F, Halsall J, Hopkins P, Robinson R. RYR1 mutations in UK central core disease patients: more than just the C-terminal transmembrane region of the RYR1 gene. J Med Genet 2004; 41: e33.
Perez CF, Voss A, Pessah IN, Allen PD. RyR1/RyR3 chimeras reveal that multiple domains of RyR1 are involved in skeletal-type E–C coupling. Biophys J 2003; 84: 2655-63.
Tammaro A, Bracco A, Cozzolino S, et al. Scanning for mutations of the ryanodine receptor (RYR1) gene by denaturing HPLC: detection of three novel malignant hyperthermia alleles. Clin Chem 2003; 49: 761-8.
Rueffert H, Olthoff D, Deutrich C, Meinecke CD, Froster UG. Mutation screening in the ryanodine receptor 1 gene (RYR1) in patients susceptible to malignant hyperthermia who show definite IVCT results: identification of three novel mutations. Acta Anaesthesiol Scand 2002; 46: 692-8.
Manning BM, Quane KA, Lynch PJ, et al. Novel mutations at a CpG dinucleotide in the ryanodine receptor in malignant hyperthermia. Hum Mutat 1998; 11: 45-50.
Monnier N, Marty I, Faure J, et al. Null mutations causing depletion of the type 1 ryanodine receptor (RYR1) are commonly associated with recessive structural congenital myopathies with cores. Hum Mutat 2008; 29: 670-8.
Loke J, MacLennan DH. Malignant hyperthermia and central core disease: disorders of Ca2+ release channels. Am J Med 1998; 104: 470-86.
Protasi F, Paolini C, Dainese M. Calsequestrin-1: a new candidate gene for malignant hyperthermia and exertional/environmental heat stroke. J Physiol 2009; 587: 3095-100.
Acknowledgement
This work was supported by grant MT-3399 to D.H.M. from the Canadian Institutes of Health Research (CIHR). There have been no commercial or non-commercial affiliations that constitute a conflict of interest with the work of any of the authors. The authors are grateful to Dr. Elena Zvaritch, University of Toronto, for ongoing discussions and for her insights into malignant hyperthermia.
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This article is accompanied by an editorial. Please see Can J Anesth 2011; 58: 6.
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Kraeva, N., Riazi, S., Loke, J. et al. Ryanodine receptor type 1 gene mutations found in the Canadian malignant hyperthermia population. Can J Anesth/J Can Anesth 58, 504–513 (2011). https://doi.org/10.1007/s12630-011-9494-6
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DOI: https://doi.org/10.1007/s12630-011-9494-6