Name: Deficit dell’enzima ramificante del glicogeno (GBED)
Brand: Equigerminal
Price: 43.05 EUR

Informazioni sul test

Il Test del DNA per la Deficienza dell'Enzima Ramificante del Glicogeno (GBED) rileva la mutazione recessiva responsabile della Deficienza dell'Enzima Ramificante del Glicogeno, un disturbo ereditario fatale che colpisce il metabolismo del glicogeno.

La GBED si eredita come un carattere autosomico recessivo. I cavalli portatori sono clinicamente normali ma possono trasmettere la mutazione ai loro discendenti. I puledri che ereditano due copie della mutazione non sono in grado di immagazzinare correttamente il glicogeno, causando aborto, morte alla nascita o morte poco dopo la nascita.

Il test del DNA consente agli allevatori di identificare i portatori e prendere decisioni di allevamento informate per prevenire la nascita di puledri affetti.

Perché testare?

Il test per GBED consente agli allevatori di:

Identificare i cavalli portatori clinicamente normali.
Evitare accoppiamenti tra portatori.
Ridurre il rischio di aborti e puledri affetti.
Confermare i casi sospetti di GBED nei puledri.
Supportare programmi di allevamento responsabili.

GBED si riscontra più comunemente in Quarter Horses, Paint Horsese razze correlate.

Segni clinici

Many affected foals are aborted or born dead. Of those born alive, most died or were put down by 8 weeks old in the published cases, and none has been found to live past 18 weeks.

Abortion late in the pregnancy, a foal born dead, or a foal born early
Weakness all over, unable to stand or to suck, lying down and not getting up
Legs that come up bent and contracted, which then straighten out again
Fits, in some foals because the blood sugar has fallen too low
Fast breathing and a fast heart, breathing failure, an irregular heartbeat, and sudden death, including after exercise
On blood tests: a low white cell count, raised muscle enzymes, and blood sugar that keeps dropping
After death the organs look almost normal to the eye

None of these signs is unique to GBED, and it is easily mistaken for other newborn diseases. Your veterinarian or a pathologist makes the diagnosis.

Trasmissione

GBED is recessive. A foal needs one copy from the sire and one from the dam to be affected. 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/GBED gives 50% n/n, 50% n/GBED
n/GBED x n/GBED gives 25% n/n, 50% n/GBED, 25% GBED/GBED

Affected foals never reach breeding age, so in practice no mating involves a GBED/GBED parent.

Prevenzione

There is no treatment, so prevention is a breeding decision.

Breeding. Mate a carrier only with a partner that tested negative, and test every foal. No affected foals are born, though some foals will be carriers. This keeps a valuable line while the variant is bred out. Being a carrier is not by itself a reason to stop breeding a horse.

An affected foal. Nothing changes the outcome. Your veterinarian guides supportive care and welfare decisions.

Risultati

Il test del DNA verifica la presenza degli alleli recessivi GBED e presenta i risultati come uno dei seguenti:

N/ - Negativo per GBED. Assenza dell'allele difettoso responsabile di GBED.
GBED/N - Portatore - Eterozigote positivo per GBED. Presenza di una copia dell'allele responsabile di GBED. Il cavallo è portatore di GBED e può trasmettere una copia dell'allele GBED alla sua progenie durante l'accoppiamento.
GBED/ -Affetto - Omozigote positivo per GBED. Presenza di due copie dell'allele responsabile di GBED. L'animale è affetto dal disturbo GBED. GBED è letale causando aborto e/o mortalità neonatale.

Requisiti di esempio

30 a 40 - radici dei capelli - busta o 5 mL - sangue - tubo K3 EDTA

Tempi di consegna

2 a 5 giorni lavorativi

Come funziona

🛒 Acquista il test: seleziona e acquista il test online.

📧 Ricevi le istruzioni: dopo la conferma del pagamento, ricevi via e-mail le istruzioni per il prelievo del campione.

📄 Compila il modulo: stampa e compila il modulo di invio campioni con l’identificazione dell’animale.

✨ Raccogli il campione: strappa da 20 a 40 radici di pelo con il bulbo e incollale nell’area indicata del modulo, oppure chiedi al tuo veterinario di prelevare il sangue in una provetta K3-EDTA.

📮 Invialo al laboratorio: Equigerminal, S.A., HIESE, Rua da Quinta do Sobreiro, 25, Quinta Vale do Espinhal, 3230-343 Penela, PORTUGAL.

📊 Ricevi il referto: il referto certificato viene emesso non appena l’analisi è convalidata.

Domande frequenti

Cos'è GBED?

GBED (Deficienza dell'enzima ramificante del glicogeno) è una malattia ereditaria fatale che impedisce l'accumulo normale di glicogeno, causando una grave carenza di energia.

I cavalli portatori possono sviluppare la malattia?

No. I cavalli portatori (N/GBED) sono clinicamente sani ma possono trasmettere la mutazione ai loro discendenti.

Come si eredita GBED?

GBED segue un pattern di ereditarietà autosomica recessiva. Un puledro affetto deve ereditare una copia mutata da ciascun genitore.

Quali razze dovrebbero essere testate?

Il test è fortemente raccomandato per Quarter Horses, Paint Horsese razze correlate a causa della frequenza relativamente alta di portatori.

Perché gli allevatori dovrebbero eseguire questo test?

Il test del DNA identifica i portatori prima dell'accoppiamento, permettendo decisioni informate che prevengono aborti e la nascita di puledri affetti, preservando al contempo linee di sangue preziose.

For Professionals

Genetic and clinical detail for veterinarians, geneticists and laboratories.

Gene / locus: GBE1 (1,4-alpha-glucan branching enzyme 1), ECA26.
Variant: c.102C>A, nonsense (premature stop codon), no functional enzyme. HGVS (EquCab3.0): NC_009169.3:g.8667651C>A; NM_001081940.2:c.102C>A; NP_001075409.1:p.(Tyr34*).
Alternative designations: Y34X; equine glycogen storage disease type IV (GSD IV), the same disease as GSD IV in humans. Laboratory allele symbol: GBED.
Variant identifiers: rs3437568674 (EVA); OMIA variant 322.
Variant classification: Pathogenic (P), ISAG/AVCG classification as listed in OMIA.
Mechanism: without branching enzyme, glycogen cannot be packed into its branched storage form; an abnormal, poorly branched polysaccharide that cannot be broken down accumulates in skeletal muscle, heart, liver and brain.
Inheritance: autosomal recessive, lethal; pedigree and genotype data consistent with a single founder (Wagner et al., 2006). OMIA code: A (autosomal).
Penetrance / expressivity: homozygotes: abortion, stillbirth or neonatal death. About 2.5% of aborted and neonatal foals of Quarter Horse-related breeds submitted to two US diagnostic laboratories were homozygous, most of them abortions; characteristic deposits were found retrospectively in 8 of 9 affected foals (Wagner et al., 2006). In the first published series, related Quarter Horse foals all died by 7 weeks: stillbirth, transient flexural deformities, seizures, respiratory or cardiac failure, or persistent recumbency (Valberg et al., 2001).
Breeds with documented carriers or cases: Quarter Horse and American Paint Horse (OMIA variant record); Quarter Horse-related breeds and crosses, including Appendix Quarter Horses; confirmed in Brazilian Quarter Horses (Araujo et al., 2018). Not found in 227 Thoroughbreds (Wagner et al., 2006). Appaloosas and Ponies of the Americas are often tested because of Quarter Horse ancestry, but no confirmed carrier is known in a published study.
Allele / carrier frequencies: carrier frequency 8.3% of 338 Quarter Horses, 7.1% of 197 Paint Horses, 0% of 227 Thoroughbreds (Wagner et al., 2006). Allele frequency 5.4% in 200 control Quarter Horses and 13.2% in western pleasure horses (Tryon et al., 2009). Carrier frequency 7.94% of 742 Brazilian Quarter Horses competing in cutting, halter, racing, reining and barrel racing (Araujo et al., 2018). Allele frequency 10.9% in elite reining Quarter Horses, unchanged over time in the random cohort (Brown et al., 2026; 300 performance and 300 random horses born 2020 to 2024). Carrier and allele frequencies are not interchangeable; for a rare recessive the allele figure is roughly half the carrier figure.
Clinical / diagnostic notes for veterinarians: consider GBED in abortion, stillbirth or weak neonates of Quarter Horse and Paint lineage. Abnormal polysaccharide deposits in cardiac muscle, skeletal muscle and liver are easily missed unless periodic acid-Schiff (PAS) staining is used; the heart is the most reliable site, but at least one confirmed affected foal showed no deposits. Erythrocyte branching-enzyme activity (about half-normal in carriers) gave only an indication and has been superseded by DNA testing.

Key references:

Ward TL, Valberg SJ, Adelson DL, Abbey CA, Binns MM, Mickelson JR (2004). Glycogen branching enzyme (GBE1) mutation causing equine glycogen storage disease IV. Mamm Genome 15:570-577. PMID 15366377.
Valberg SJ, Ward TL, Rush B, Kinde H, Hiraragi H, Nahey D, Fyfe J, Mickelson JR (2001). Glycogen branching enzyme deficiency in Quarter Horse foals. J Vet Intern Med 15:572-580.
Ward TL, Valberg SJ, Lear TL, Guerin G, Milenkovic D, Swinburne JE, et al. (2003). Genetic mapping of GBE1 and its association with glycogen storage disease IV in American Quarter horses. Cytogenet Genome Res 102:201-206. doi:10.1159/000075749.
Wagner ML, Valberg SJ, Ames EG, Bauer MM, Wiseman JA, Penedo MCT, Kinde H, Abbitt B, Mickelson JR (2006). Allele frequency and likely impact of the glycogen branching enzyme deficiency gene in Quarter Horse and Paint Horse populations. J Vet Intern Med 20:1207-1211.
Tryon RC, Penedo MCT, McCue ME, et al. (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.
Araujo CET, Delfiol DJZ, Badial PR, Oliveira-Filho JP, Araujo-Junior JP, Borges AS (2018). Prevalence of the glycogen branching enzyme deficiency mutation in Quarter Horses in Brazil. J Equine Vet Sci 62:81-84. doi:10.1016/j.jevs.2017.10.010.
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.