Name: MH Hipertermia Maligna
Brand: Equigerminal
Price: 43.05 EUR

Sobre o teste

Este teste de DNA deteta a Hipertermia Maligna (HM) mutação, uma doença genética hereditária que afeta a função muscular esquelética em Quarter Horses e raças relacionadas.

O teste identifica se um cavalo está livre ou afetado pela mutação dominante da HM, apoiando decisões de reprodução e gestão clínica antes da anestesia ou exercício intenso.

Porquê testar?

Este teste genético ajuda a:

Identificar cavalos portadores da mutação dominante MH.
Apoiar decisões responsáveis de reprodução.
Avaliar o risco de hipertermia maligna antes da anestesia.
Identificar cavalos com risco aumentado de crises musculares induzidas por exercício ou stress.
Detetar cavalos que também podem beneficiar de testes adicionais PSSM1 .

Sinais clínicos

Signs usually appear in adult horses. Two kinds of attack are on record.

Attacks under anaesthesia:

Body temperature climbing fast, recorded between 40 and 45 degrees Celsius. In one monitored case it rose about 0.12 degrees every minute.
A racing heart that loses its rhythm, and high blood pressure
Heavy sweating. The anaesthetic tubing becomes hot to the touch.
Muscles locking up: first in one place, such as the ears drawn in or the jaw clamped shut, then all over, with the third eyelid showing and the eye pulled back into the socket
The blood turning acid, with carbon dioxide building up even though the horse is on a ventilator with pure oxygen
Blood salts out of balance, thickened blood, high blood sugar, struggling kidneys and muscle breakdown products rising fast
Death, with the body stiffening unusually quickly afterwards

Attacks with no anaesthetic involved:

Severe, sudden muscle breakdown with a body temperature recorded between 40.2 and 43.3 degrees Celsius
Episodes that look like colic, locked muscles, a stiff way of going, tiring quickly, sweating on and off, a fast heart and fast breathing
Extremely high muscle enzymes on a blood test, and acid blood
Muscle enzymes that stay raised between attacks, in horses that otherwise look well
Sudden death, including death out in the field on an unusually hot day

What sets off an attack: every gas anaesthetic of the halogenated family (halothane, isoflurane, desflurane, sevoflurane) and muscle relaxants such as succinylcholine. Also exercise, the stress of transport or a new place, the start of training, the excitement of breeding, extreme heat, and another illness or muscle disease at the same time.

An attack is a veterinary emergency. What is reported to save horses: spotting it early, stopping the anaesthetic gas or muscle relaxant at once, cooling the body actively, and giving dantrolene.

None of these signs is unique to MH. They also happen under anaesthesia and after hard work for other reasons. Your veterinarian makes the diagnosis from the history, the examination, blood results and this genetic result.

Transmissão

MH is dominant. One copy is enough to make a horse susceptible. The gene is not on a sex chromosome, so colts and fillies are affected equally. Through a positive parent, the variant can pass into other breeds and lines.

What each mating can produce:

n/n x n/n gives 100% n/n
n/n x n/MH gives 50% n/n, 50% n/MH
n/MH x n/MH gives 25% n/n, 50% n/MH, 25% MH/MH

No horse with two copies has been found yet. The researchers put this down to how rare the disease is, not to any evidence that two copies would be lethal.

Prevenção

There is no cure. The result guides two things.

Managing a positive horse. This part saves lives, and it belongs to your veterinarian:

Ask your veterinarian to record the result in the horse's clinical file, so it is known before any general anaesthesia and in an emergency
Medication can be given before anaesthesia to reduce the severity of an attack
Avoid the other triggers listed under Clinical signs where you can
A horse that also carries PSSM1 needs that condition managed as well

Breeding. Breeding from positive horses is discouraged. Test breeding stock before mating, and if a positive horse is used, choose a partner that tested negative.

Descrição dos resultados

O teste de DNA verifica a presença do gene dominante MH e apresenta os resultados como um dos seguintes:

N/ - Negativo para MHAusência do alelo responsável pela Hipertermia Maligna (MH).
MH/N - Afetado - Heterozigoto positivo para MHPresença de uma cópia do alelo responsável pela MH. O cavalo está afetado pela desordem MH e pode transmitir o alelo MH a 50% da sua descendência quando reproduzido.
MH/ -Afetado - Homozigoto positivo para MHPresença de duas cópias do alelo responsável pela MH. O cavalo está afetado pela desordem MH e transmitirá o alelo MH a 100% da sua descendência.

Requisitos da amostra

30 a 40 - raízes de crinas - envelope ou 5 mL - sangue - tubo K3 EDTA

Envie a sua amostra por correio normal para:

Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal

Tempo de resposta

Processamento padrão: resultados no prazo de 5 a 10 dias úteis após a chegada da amostra ao laboratório. O envio é organizado e pago pelo cliente, e o tempo de transporte não está incluído nos 5 a 10 dias úteis.

As amostras que falhem a extração ou a amplificação de ADN são repetidas sem custo adicional, o que pode acrescentar alguns dias úteis. Contactamo-lo se for necessária uma nova amostra.

Como funciona

🛒 Compre o teste: selecione e compre o teste online.

📧 Receba as instruções: após a confirmação do pagamento, recebe por email as instruções de recolha da amostra.

✨ Recolha a amostra: arranque 20 a 40 raízes de pelo com o bolbo, ou peça ao seu veterinário que colha sangue num tubo K3-EDTA.

📄 Preencha o formulário: imprima e preencha o formulário de submissão com a identificação do animal.

📮 Envie para o laboratório: Equigerminal, S.A., HIESE, Rua da Quinta do Sobreiro, 25, Quinta Vale do Espinhal, 3230-343 Penela, PORTUGAL.

📄 Receba o relatório: o relatório certificado é emitido assim que a análise for validada.

FAQs

Quais amostras podem ser enviadas?

O teste pode ser realizado usando 30–40 raízes de crinas ou 5 mL de sangue recolhido num tubo K3 EDTA.

Por que devo testar para Hipertermia Maligna?

O teste identifica cavalos portadores da mutação MH, permitindo decisões de reprodução informadas e ajudando os veterinários a reduzir os riscos anestésicos através de uma gestão adequada.

Quais cavalos são mais frequentemente afetados?

A mutação é encontrada principalmente em Quarter Horses e raças relacionadas, embora o teste possa ser apropriado sempre que houver uma genealogia relevante ou suspeita clínica.

Devo também testar para PSSM1?

Sim. Cavalos portadores das mutações MH e PSSM1 podem desenvolver sinais clínicos mais graves, por isso recomenda-se testar ambas as condições em raças suscetíveis.

Quanto tempo demora a receber os resultados?

Os resultados estão disponíveis dentro de 2 a 5 dias úteis após a chegada da amostra ao laboratório.

For Professionals

Genetic and clinical detail for veterinarians, geneticists and laboratories.

Gene / locus: RYR1 (ryanodine receptor 1), ECA10.
Variant: missense Arg to Gly. HGVS (EquCab3.0): NC_009153.3:g.9678680C>G; XM_023649662.1:c.7363C>G; XP_023505430.1:p.(Arg2455Gly).
Alternative designations: published as c.7360C>G, p.(Arg2454Gly) (R2454G; Aleman et al., 2004). OMIA restates it against transcript XM_023649662.1, giving c.7363C>G and R2455G; both designations refer to the same genomic change. Laboratories differ in which they print, so quote both when comparing reports.
Discovery: candidate-gene approach from the homologous disease in pigs and humans; the change was found in two affected horses (Aleman et al., 2004). The homologous position is altered in two of the five known human malignant hyperthermia susceptibility types.
Mechanism: RYR1 encodes the calcium release channel of skeletal muscle. In susceptible horses the channel can be forced open, flooding the cell with calcium; hypermetabolism follows, with intense heat production and acidosis, and often death.
Variant identifiers: no rs/EVA identifier listed in OMIA; OMIA variant 159.
Variant classification: not currently evaluated (ISAG/AVCG, per OMIA).
Inheritance: autosomal dominant (OMIA code D), inferred from two heterozygous affected horses; no formal pedigree analysis has been published (Aleman et al., 2004, as cited in OMIA).
Penetrance / expressivity: estimated mortality 34% in susceptible horses under halothane anaesthesia (Aleman et al., 2009). PSSM phenotype is more severe in horses carrying both RYR1 and GYS1 variants (McCue et al., 2009).
Breeds with documented carriers or cases: Quarter Horse, Appaloosa, American Paint Horse (OMIA variant record). All horses in the first clinical series were Quarter Horses of halter lines. The clinical syndrome has also been reported in Thoroughbreds, Arabians and ponies, not all attributed to this variant.
Allele / carrier frequencies: among 159,227 horses of 16 breeds, the variant was found in 391 Quarter Horses, 18 Paint Horses, 1 Appaloosa and 1 Quarter Horse x Clydesdale; allele frequency 0.13% in Quarter Horses and 0.12% in Paint Horses and Appaloosas (Aleman, McCue and Bellone, 2025).
Clinical notes for veterinarians: consider concurrent GYS1 (PSSM1) testing in Quarter Horse-related breeds.

Key references:

Aleman M, Riehl J, Aldridge BM, LeCouteur RA, Stott JL, Pessah IN (2004). Association of a mutation in the ryanodine receptor 1 gene with equine malignant hyperthermia. Muscle Nerve 30:356-365. doi:10.1002/mus.20084. PMID 15318347.
Aleman M, Nieto JE, Magdesian KG (2009). Malignant hyperthermia associated with ryanodine receptor 1 mutation in Quarter Horses. J Vet Intern Med 23:329-334. doi:10.1111/j.1939-1676.2009.0274.x.
McCue ME, Valberg SJ, Jackson M, Borgia L, Lucio M, Mickelson JR (2009). Polysaccharide storage myopathy phenotype in Quarter Horse-related breeds is modified by the presence of an RYR1 mutation. Neuromuscul Disord 19:37-43. doi:10.1016/j.nmd.2008.10.001.
Aleman M, McCue M, Bellone RR (2025). Allele frequencies and genotypes for the ryanodine receptor 1 variant causing malignant hyperthermia and fatal rhabdomyolysis with hyperthermia in horses. J Vet Intern Med 39:e70081. doi:10.1111/jvim.70081.
Sperandio LMS, Lago GR, Albertino LG, Araujo CET, Ferreira C, Borges AS, Oliveira-Filho JP (2024). Allele frequency of muscular genetic disorders in bull-catching (vaquejada) Quarter Horses. J Equine Vet Sci 136:105052. doi:10.1016/j.jevs.2024.105052.