Name: HYPP Paralisia Periódica Hipercalémica
Brand: Equigerminal
Price: 43.05 EUR

Sobre o teste

Este teste de DNA verifica a presença da Paralisia Periódica Hipercalémica (HYPP) variante genética.

Porquê testar?

Este teste genético ajuda os criadores a identificar cavalos portadores da variante genética HYPP, permitindo decisões de reprodução informadas e ajudando a prevenir o nascimento de poldros afetados.

Todos os descendentes de Impressive devem ser testados para HYPP.

Como a HYPP é uma doença dominante, a mutação pode também ocorrer em outras raças de cavalos através do cruzamento.

O teste é também recomendado para cavalos que apresentem sinais clínicos compatíveis com HYPP.

Sinais clínicos

Attacks come and go and vary a lot from horse to horse, from barely noticeable to collapse or sudden death. Between attacks the muscles work normally.

Muscle twitching and trembling, sometimes continuous, that can progress to weakness, paralysis and the horse going down
The horse stays conscious and does not seem to be in pain
Spasm of the face muscles, the third eyelid sliding across the eye, drooling, and sweating while body temperature stays normal
Noisy breathing and blue gums as the throat muscles go slack and block the airway; trouble swallowing and a changed whinny
Heavy, well-developed muscling, sometimes very marked
Tiring quickly in work; attacks that can look like colic or staggering, or leave the horse sitting like a dog
In severe attacks, an abnormal heart rhythm and sudden death
Attacks often follow a change of feed, a period without food, a stressful event or a meal rich in potassium

None of these signs is unique to HYPP, and HYPP is not the same as tying up, colic or a seizure. Your veterinarian decides whether a horse is ill, using the history, the examination, blood results and this result.

Transmissão

HYPP 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.

What each mating can produce:

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

Prevenção

There is no cure. The result guides two things.

Breeding. Only a mating between two horses that tested negative is sure to give no affected foals. Breeding from positive horses is not recommended.

Managing a positive horse. The measures reported are:

A diet low in potassium, with grass hay rather than alfalfa
Regular smaller meals instead of large irregular ones, and no sudden changes of feed
Salt available at all times
Daily exercise and turnout instead of long spells in a stable
Telling your veterinarian and anaesthetist the result before any operation, because general anaesthesia can set off an attack

Some medicines that make the horse pass more urine have been reported to make attacks less frequent and less severe. Horses with two copies have been managed with medical and surgical treatment. Your veterinarian sets the diet, monitoring and any treatment.

Descrição dos resultados

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

N/ – Normal - Ausência do alelo responsável pela HYPP.
N/H – Afetado - Heterozigótico positivo para HYPP. Presença de uma cópia do alelo responsável pela HYPP. O cavalo está afetado pela desordem HYPP e há 50% de chance de este cavalo transmitir um alelo HYPP à sua descendência.
H/ – Afetado - Homozigótico positivo para HYPPPresença de duas cópias do alelo responsável pela HYPP. O cavalo está afetado pela desordem HYPP e há 100% de chance de este cavalo transmitir um alelo HYPP à sua descendência.

Requisitos da amostra

30 a 40 raízes capilares ou 5 mL de sangue em 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

Que amostras podem ser enviadas?

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

Que cavalos devem ser testados?

Recomenda-se o teste para todos os descendentes de Impressive, cavalos destinados à reprodução e cavalos que apresentem sinais clínicos compatíveis com HYPP.

O que significam os resultados?

N/N: O cavalo está livre da mutação HYPP.
N/H: O cavalo está afetado e tem 50% de probabilidade de transmitir a mutação à sua descendência.
H/H: O cavalo está afetado e transmitirá a mutação a toda a descendência.

A HYPP é uma doença recessiva?

Não. Embora o texto original se refira incorretamente a um gene recessivo em alguns locais, a HYPP é uma doença genética dominante. Tanto os N/H como os H/H cavalos estão afetados, enquanto apenas os N/N cavalos não estão afetados.

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: SCN4A (sodium voltage-gated channel alpha subunit 4, skeletal muscle), ECA11.
Variant: F1416L (Phe1416Leu), missense. HGVS (EquCab3.0): NC_009154.3:g.15474228C>G; NM_001081761.1:c.4248C>G; NP_001075230.1:p.(Phe1416Leu).
Alternative designations: H allele (OMIA allele symbol); Impressive syndrome, after the founder stallion.
Variant identifiers: rs1148998534 (EVA); OMIA variant 162.
Variant classification: not currently evaluated (ISAG/AVCG, per OMIA).
Mechanism: impaired sodium channel inactivation (Cannon et al., 1995). Persistent sodium influx leaves the muscle membrane hyperexcitable. The defect is unmasked by rises in serum potassium, which links episodes to feeding.
Evidence of causality: complete co-segregation of SCN4A with HYPP in families (Rudolph et al., 1992b), followed by identification of the causal variant (Rudolph et al., 1992a). This was the first equine disease with an identified causal variant.
Inheritance: autosomal incomplete dominant (OMIA code AID); homozygotes more severely affected than heterozygotes, described as co-dominant (Naylor et al., 1999).
Penetrance / expressivity: variable; most affected horses show no signs until mature and in training.
Breeds with documented carriers or cases: Quarter Horse (OMIA variant record), Quarter Horse crosses including Appendix Quarter Horses, and American Paint Horses of Quarter Horse descent. All carriers traced to a single founder, the Quarter Horse stallion Impressive, born 1969 (Bowling et al., 1996). The variant spread through selection for heavy muscling. The Appaloosa is not listed because no source was found.
Allele / carrier frequencies: allele frequency by discipline in American Quarter Horses (Tryon et al., 2009; 651 elite performance and 200 control horses): 0% in cutting, working cow, reining and racing; 0.6% in barrel racing; 1.3% in western pleasure; 29.9% in halter; 0.8% in the general Quarter Horse population. Allele frequency 31.8% in halter horses, with no change over time in the random cohort (Brown et al., 2026; 300 performance horses across seven disciplines and 300 random Quarter Horses born 2020 to 2024).
Homozygote phenotype: in Naylor et al. (1999), all 9 H/H horses had respiratory stridor, usually within the first week of life; 5 had dysphagia, 3 ptyalism and 3 weight loss. Six of the 9 died or were euthanised (4 before one year, 1 at 20 months, 1 at five years). Of 35 contemporaneous half siblings, 1 had stridor before weaning and none had dysphagia. On potassium challenge, H/H horses showed ptyalism, third eyelid prolapse, stridor and weakness far more often than n/H horses.
Clinical / diagnostic notes for veterinarians: the DNA test has replaced potassium challenge (false negatives) and electromyography (abnormalities not specific to HYPP). Muscle biopsy is not diagnostic for HYPP but can help exclude other myopathies. Hyperkalaemia has other causes, and serum potassium can be falsely raised by the sample itself. The American Quarter Horse Association treats HYPP as a defect, does not register H/H horses and registers n/H horses.

Key references:

Rudolph JA, Spier SJ, Byrns G, Rojas CV, Bernoco D, Hoffman EP (1992a). Periodic paralysis in Quarter Horses: a sodium channel mutation disseminated by selective breeding. Nat Genet 2:144-147. doi:10.1038/ng1092-144. PMID 1338908.
Rudolph JA, Spier SJ, Byrns G, Hoffman EP (1992b). Linkage of hyperkalaemic periodic paralysis in Quarter Horses to the horse adult skeletal muscle sodium channel gene. Anim Genet 23:241-250.
Cannon SC, Hayward LJ, Beech J, Brown RH Jr (1995). Sodium channel inactivation is impaired in equine hyperkalemic periodic paralysis. J Neurophysiol 73:1892-1899.
Naylor JM, Nickel DD, Trimino G, Card C, Lightfoot K, Adams G (1999). Hyperkalaemic periodic paralysis in homozygous and heterozygous horses: a co-dominant genetic condition. Equine Vet J 31:153-159.
Bowling AT, Byrns G, Spier S (1996). Evidence for a single pedigree source of the hyperkalemic periodic paralysis susceptibility gene in Quarter Horses. Anim Genet 27:279-281.
Tryon RC, Penedo MCT, McCue ME, Valberg SJ, Mickelson JR, Famula TR, Wagner ML, Jackson M, Hamilton MJ, Nooteboom S, Bannasch DL (2009). Evaluation of allele frequencies of inherited disease genes in subgroups of American Quarter Horses. J Am Vet Med Assoc 234:120-125. doi:10.2460/javma.234.1.120.
Brown BN, Hughes S, Le TM, Tatar NP, Grahn JC, Carrillo-Alvarez M, Bellone RR, Finno CJ (2026). Allele frequencies of 7 inherited disorders in performance and random cohorts of American Quarter Horses (2020-2024). J Am Vet Med Assoc 1-7. doi:10.2460/javma.26.04.0256.