Polymorphisms and deduced amino acid substitutions in the coding sequence of the ryanodine receptor (RYR1) gene in individuals with malignant hyperthermia

More than 80 mutations in the skeletal muscle ryanodine receptor gene have been found to be associated with autosomal dominant forms of malignant hyperthermia and central core disease, and with recessive forms of multi-minicore disease. Studies on the functional effects of pathogenic dominant mutations have shown that they mostly affect intracellular Ca2+ homoeostasis, either by rendering the channel hypersensitive to activation (malignant hyperthermia) or by altering the amount of Ca2+ released subsequent to physiological or pharmacological activation (central core disease). In the present paper, we show, for the first time, data on the functional effect of two recently identified recessive ryanodine receptor 1 amino acid substitutions, P3527S and V4849I, as well as that of R999H, another substitution that was identified in two siblings that were affected by multi-minicore disease. We studied the intracellular Ca2+ homoeostasis of EBV (Epstein–Barr virus)-transformed lymphoblastoid cells from the affected patients, their healthy relatives and control individuals. Our results show that the P3527S substitution in the homozygous state affected the amount of Ca2+ released after pharmacological activation with 4-chloro-m-cresol and caffeine, but did not affect the size of the thapsigargin-sensitive Ca2+ stores. The other substitutions had no effect on either the size of the intracellular Ca2+ stores, or on the amount of Ca2+ released after ryanodine receptor activation; however, both the P3527S and V4849I substitutions had a small but significant effect on the resting Ca2+ concentration.

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Polymorphism in the coding sequence of the horse transferrin gene

Genome ◽

10.1139/g94-020 ◽

1994 ◽

Vol 37 (1) ◽

pp. 157-165 ◽

Cited By ~ 7

Author(s):

Margaret A. Carpenter ◽

Tom E. Broad

Keyword(s):

Amino Acid ◽

Iron Transport ◽

Nucleotide Substitution ◽

Three Dimensional ◽

Sequence Polymorphism ◽

Dimensional Structure ◽

Amino Acid Substitutions ◽

Nucleotide Substitutions ◽

Coding Sequence ◽

Transferrin Gene

Transferrin, the iron transport protein of the blood, is highly polymorphic in many species, including the horse. A number of sequence polymorphisms that distinguish several of the variants of horse transferrin are reported here. Previous studies indicated that exons 12 and 15 were likely to be polymorphic. Sequencing regions of exons 12 and 15 from D and R variants revealed 10 nucleotide substitutions that encoded six amino acid replacements. The F1, F2, H2, and * variants were identical to D, and the O variant was almost identical to R, in the regions studied. The data indicated that the horse transferrin variants make up two distinct groups. The positions of differences between the D and F1 alleles were determined by analyzing single-stranded conformation polymorphisms. Sequencing then revealed three nucleotide substitutions, two of which encoded amino acid substitutions. Location of the eight polymorphic residues on the three-dimensional structure of human lactoferrin revealed that all were clustered at one end of the C-lobe.Key words: sequence polymorphism, transferrin, horse, nucleotide substitution, allele.

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Amino acid substitutions within the 2C coding sequence of Theiler's Murine Encephalomyelitis virus alter virus growth and affect protein distribution

Virus Research ◽

10.1016/j.virusres.2009.04.001 ◽

2009 ◽

Vol 144 (1-2) ◽

pp. 74-82 ◽

Cited By ~ 6

Author(s):

Lindsay Murray ◽

Garry A. Luke ◽

Martin D. Ryan ◽

Thomas Wileman ◽

Caroline Knox

Keyword(s):

Amino Acid ◽

Amino Acid Substitutions ◽

Protein Distribution ◽

Theiler's Murine Encephalomyelitis Virus ◽

Virus Growth ◽

Coding Sequence ◽

Theiler’S Murine Encephalomyelitis Virus ◽

Encephalomyelitis Virus

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Results of Contracture Tests with Halothane, Caffeine, and Ryanodine Depend on Different Malignant Hyperthermia-associated Ryanodine Receptor Gene Mutations

Anesthesiology ◽

10.1097/00000542-200208000-00010 ◽

2002 ◽

Vol 97 (2) ◽

pp. 345-350 ◽

Cited By ~ 16

Author(s):

Marko Fiege ◽

Frank Wappler ◽

Ralf Weisshorn ◽

Mark Ulrich Gerbershagen ◽

Markus Steinfath ◽

...

Keyword(s):

Malignant Hyperthermia ◽

Ryanodine Receptor ◽

Time Course ◽

Clinical Symptoms ◽

Receptor Gene ◽

Gene Mutations ◽

Onset Time ◽

Release Channel ◽

Ryr1 Gene

Background More than 20 mutations in the gene encoding for the ryanodine receptor (RYR1), a Ca2+ release channel of the skeletal muscle sarcoplasmic reticulum, have been found to be associated with malignant hyperthermia (MH). This study was designed to investigate the effects of different mutations in the RYR1 gene on contracture development in in vitro contracture tests (IVCT) with halothane, caffeine, and ryanodine. Methods Ninety-three MH-susceptible (MHS) patients, diagnosed by the standard IVCT with halothane and caffeine, were included in this prospective study. Surplus muscle specimens were used for an IVCT with 1 microm ryanodine. The contracture course during the ryanodine IVCT was described by the attainment of different time points: onset time of contracture and times when contracture reached 2 mN or 10 mN. In addition, all patients were screened for mutations of the RYR1 gene. Results In 36 patients, four different mutations of the RYR1 gene (C487-T, G1021-A, C1840-T, G7300-A) were found. The IVCT threshold concentrations of halothane and caffeine were lower in patients with the C487-T mutation compared with patients without a detected mutation in the RYR1 gene. In the IVCT with ryanodine, contracture levels of 2 mN and 10 mN were reached earlier in muscle specimens from patients with C487-T, C1840-T, and G7300-A mutations compared with specimens from patients with the G1021-A mutation and patients without detected mutation in the RYR1 gene. Conclusions The differences between the groups in the halothane and caffeine IVCT threshold concentrations and in the time course of contracture development in the ryanodine IVCT underline the hypothesis that certain mutations in the RYR1 gene could make the ryanodine receptor more sensitive to specific ligands. This may be an explanation for varying clinical symptoms of MH crisis in humans.

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Scanning for Mutations of the Ryanodine Receptor (RYR1) Gene by Denaturing HPLC: Detection of Three Novel Malignant Hyperthermia Alleles

Clinical Chemistry ◽

10.1373/49.5.761 ◽

2003 ◽

Vol 49 (5) ◽

pp. 761-768 ◽

Cited By ~ 31

Author(s):

Angela Tammaro ◽

Adele Bracco ◽

Santolo Cozzolino ◽

Maria Esposito ◽

Antonietta Di Martino ◽

...

Keyword(s):

Skeletal Muscle ◽

Malignant Hyperthermia ◽

Ryanodine Receptor ◽

Sudden Increase ◽

Gene Encoding ◽

In Vitro Contracture Test ◽

Ryr1 Gene ◽

Molecular Tests ◽

Anesthetic Agents

Abstract Background: Malignant hyperthermia (MH) is a fatal autosomal dominant pharmacogenetic disorder characterized by skeletal muscle hypertonicity that causes a sudden increase in body temperature after exposure to common anesthetic agents. The disease is genetically heterogeneous, with mutations in the gene encoding the skeletal muscle ryanodine receptor (RYR1) at 19q13.1 accounting for up to 80% of the cases. To date, at least 42 RYR1 mutations have been described that cause MH and/or central core disease. Because the RYR1 gene is huge, containing 106 exons, molecular tests have focused on the regions that are more frequently mutated. Thus the causative defect has been identified in only a fraction of families as linked to chromosome 19q, whereas in others it remains undetected. Methods: We used denaturing HPLC (DHPLC) to analyze the RYR1 gene. We set up conditions to scan the 27 exons to identify both known and unknown mutations in critical regions of the protein. For each exon, we analyzed members from 52 families with positive in vitro contracture test results, but without preliminary selection by linkage analysis. Results: We identified seven different mutations in 11 MH families. Among them, three were novel MH alleles: Arg44Cys, Arg533Cys, and Val2117Leu. Conclusion: Because of its sensitivity and speed, DHPLC could be the method of choice for the detection of unknown mutations in the RYR1 gene.

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Therapeutic effects of novel type 1 ryanodine receptor inhibitor on malignant hyperthermia

The Journal of General Physiology ◽

10.1085/jgp.2021ecc48 ◽

2021 ◽

Vol 154 (9) ◽

Author(s):

Toshiko Yamazawa

Keyword(s):

Skeletal Muscle ◽

Malignant Hyperthermia ◽

Ryanodine Receptor ◽

Half Life ◽

Water Solubility ◽

Heat Stroke ◽

Therapeutic Effects ◽

Ryr1 Gene ◽

Plasma Half Life

Ca2+-induced Ca2+ release (CICR) is mediated by ryanodine receptors, a Ca2+ release channel in the sarcoplasmic/endoplasmic reticulum (SR/ER), and plays an important role in various tissues. Type 1 ryanodine receptor (RYR1) plays a key role during excitation–contraction coupling of skeletal muscle. Mutations in RYR1 overactivate the channel to cause malignant hyperthermia (MH). MH is a serious complication characterized by skeletal muscle rigidity and elevated body temperature in response to commonly used inhalational anesthetics. Thus far, >300 mutations in the RYR1 gene have been reported in patients with MH. Some heat stroke triggered by exercise or environmental heat stress is also related to MH mutations in the RYR1 gene. The only drug approved for ameliorating the symptoms of MH is dantrolene, which has been first developed in the 1960s as a muscle relaxant. However, dantrolene has several disadvantages for clinical use: poor water solubility, which makes rapid preparation difficult in emergency situations, and long plasma half-life, which causes long-lasting side effects such as muscle weakness. Here, we show that a novel RYR1-selective inhibitor, 6,7-(methylenedioxy)-1-octyl-4-quinolone-3-carboxylic acid (compound 1 [Cpd1]), effectively rescues MH and heat stroke in new mouse model (RYR1-p.R2509C) relevant to MH. Cpd1 has great advantages of higher water solubility and shorter plasma half-life compared with dantrolene. Our data suggest that Cpd1 has the potential to be a promising new candidate for effective treatment of patients carrying RYR1 mutations. Finally, we have recently identified that heat directly activates RYR1, which induces Ca2+ release from intracellular stores. Our results provide direct evidence that heat induces Ca2+ release (HICR) from the SR through the mutants rather than wild type RYR1, causing an immediate rise in the cytosolic Ca2+ concentration.

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Mutations in the Skeletal Muscle Ryanodine Receptor (RYR1) Gene are Linked to Malignant Hyperthermia and Central-Core Disease

Malignant Hyperthermia ◽

10.1007/978-4-431-68346-9_12 ◽

1996 ◽

pp. 79-86 ◽

Cited By ~ 1

Author(s):

David H. MacLennan

Keyword(s):

Skeletal Muscle ◽

Malignant Hyperthermia ◽

Ryanodine Receptor ◽

Central Core ◽

Central Core Disease ◽

Ryr1 Gene

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Fatal postoperative malignant hyperthermia following rhinoplasty in a patient with one variant of the ryanodine receptor 1 (RYR1) gene

Legal Medicine ◽

10.1016/j.legalmed.2021.101938 ◽

2021 ◽

pp. 101938

Author(s):

Jia-Wen Wang ◽

Dong Qu ◽

Man Li ◽

Bing Xia ◽

Chang-Wu Wan ◽

...

Keyword(s):

Malignant Hyperthermia ◽

Ryanodine Receptor ◽

Ryr1 Gene ◽

Ryanodine Receptor 1

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Unexpected predicted length variation for the coding sequence of the sleep related gene, BHLHE41 in gorilla amidst strong purifying selection across mammals

10.1101/773770 ◽

2019 ◽

Author(s):

Krishna Unadkat ◽

Justen B. Whittall

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Sequence Alignment ◽

Clock Genes ◽

Phylogenetic Analyses ◽

Purifying Selection ◽

Amino Acid Substitutions ◽

Length Variation ◽

Coding Sequence ◽

Circadian Clock Genes

AbstractThere is a molecular basis for many sleep patterns and disorders involving circadian clock genes. In humans, “short-sleeper” behavior has been linked to specific amino acid substitutions in BHLHE41 (DEC2), yet little is known about variation at these sites and across this gene in mammals. We compare BHLHE41 coding sequences for 27 mammals. The coding sequence alignment length was 1794bp, of which 55.0% of base pairs were invariant among the sampled mammals. The mean pairwise nucleotide identity was 92.2%. Of the 598 residue amino acid alignment for mammals, 71.7% of amino acids were identical. The pairwise percent identity for amino acids was 94.8%. No other mammals had the same “short-sleeper” amino acid substitutions previously described from humans. Phylogenetic analyses based on the nucleotides of the coding sequence alignment are consistent with established mammalian relationships. Significant purifying selection was detected in 66.2% of variable codons. No codons exhibited significant signs of positive selection. Unexpectedly, the gorilla BHLHE41 sequence has a 318 bp insertion at the 5’ end of the coding sequence and a deletion of 195 bp near the 3’ end of the coding sequence (including the two short sleeper variable sites). Given the strong signal of purifying selection across this gene, phylogenetic congruence with expected relationships and generally conserved function among mammals investigated thus far, we suggest the unexpected indels predicted in the gorilla BHLHE41 may represent an annotation error and warrant experimental validation.

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