Alvorlig kombineret immundefekt - SCID
DNA-test for svær kombineret immundefekt (SCID). SCID er en arvelig sygdom, der ses hos rene og delavlede arabiske heste. Eksempel...
€43.05 Inkl. moms
Om testen
Denne DNA-testdetekterer Severe Combined Immunodeficiency (SCID)-mutationen, en arvelig genetisk lidelse, der primært findes hos fuldblods- og halvarabiske heste. Testen identificerer heste, der er raske, bærere eller påvirkede, hvilket understøtter ansvarlige avlsbeslutninger.
Hvorfor teste?
Breeding. Two carriers can produce an affected foal. Knowing the result of both parents tells you what each mating can produce.
A foal with repeated infections. Its signs look like many common foal infections, so looking at the foal is not enough. The test shows whether SCID is the cause.
Avoiding a costly loss. An affected foal is distressing for the animal and the people caring for it, and costly in lost foals and veterinary expenses.
Kliniske tegn
Føl, der er ramt af SCID, udvikler typisk:
- Tilbagevendende luftvejsinfektioner
- Vedvarende diarré
- Feber
- Manglende trivsel
- Alvorlig immundefekt
- Øget modtagelighed over for bakterielle og virale infektioner
Kliniske tegn viser sig som regel mellem 2 dage og 8 uger gamle, og ramte føl overlever sjældent længere end seks måneder.
Transmission
SCID er en autosomal recessiv arvelig lidelse. Et føl skal arve én muteret allel fra hver forælderfor at blive ramt. Heste, der kun bærer én kopi af mutationen, forbliver klinisk normale, men kan give mutationen videre til 50% af deres afkom.
Forebyggelse
Der findes ingen behandling eller kurfor SCID. Forebyggelse beror på genetisk testning før avl. Bærerheste kan stadig trygt avles, forudsat at de kun parres med heste, der er testet fri (N/N)for SCID-mutationen.
Resultater
DNA-testen verificerer tilstedeværelsen af den recessive SCID-mutation og præsenterer resultaterne som et af følgende:
- nn – Ikke-bæreraf SCID-genet. Testet negativ for SCID-mutationen.
- nSCID – Heterozygot hest for SCID-genet; både det normale og SCID-alleler blev påvist. Hesten er bærer af den genetiske SCID-lidelse, og der er 50 % sandsynlighed for, at denne hest vil videregive et SCID-allel til sit afkom.
- SCID SCID– Bærer af to kopier af SCID-genet. Homozygot hest for SCID-mutation. Hesten er ramt af den genetiske SCID-lidelse.
Krav til prøver
30 til 40 - hårrødder - kuvert eller 5 ml - blod - K3 EDTA-glas
Send din prøve med almindelig post eller ekspreslevering til:
Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal
Behandlingstid
2 til 5 arbejdsdage
Sådan fungerer det
🛒 Køb testen:Vælg og køb testen online.
📧 Modtag instruktioner:Efter betalingsbekræftelse modtager du instruktioner til prøvetagning.
✨ Prøvetagning:Din dyrlæge indsamler hårrødder eller en blodprøve.
📄 Download indsendelsesformular:Download den printbare indsendelsesformular.
📮 Send prøver:Send dine prøver med almindelig post eller ekspreslevering til:
Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal
📄 Modtag resultater:Du modtager dit resultatcertifikat via e-mail.
Ofte stillede spørgsmål
Hvilke racer bør testes?
Test anbefales for rene arabiske heste, delvis arabiske hesteog heste med arabisk afstamning.
Kan bærerheste avles?
Ja. Bærerheste kan trygt avles med SCID-fri (N/N)heste uden at producere berørte føl.
Kan SCID behandles?
Nej. Der er i øjeblikket ingen kur mod SCID. Forebyggelse gennem genetisk testning er den mest effektive strategi.
Hvilke prøver accepteres?
Testen kan udføres ved brug af 30–40 hårrøddereller 5 ml blod opsamlet i et K3 EDTA-rør.
Hvornår modtager jeg mine resultater?
Resultater er tilgængelige inden for 2 til 5 arbejdsdageefter prøvens ankomst til laboratoriet.
For Professionals
Genetic and clinical detail for veterinarians, geneticists and laboratories.
- Gene / locus: PRKDC (protein kinase, DNA-activated, catalytic subunit; DNA-PKcs), ECA9.
- Variant: 5-bp deletion causing a frameshift, truncated kinase-negative protein (Shin et al., 1997). HGVS (EquCab3.0): NC_009152.3:g.36395752_36395756del; NM_001163858.1:c.9478_9482del; NP_001157330.1:p.(Asn3160fs*3).
- Alternative designations: OMIA notes that the genomic coordinates were previously listed incorrectly as g.36395752_36395759del (corrected 03/06/2024). Laboratory allele symbol: SCID.
- Variant identifiers: no rs/EVA identifier listed in OMIA; OMIA variant 511.
- Variant classification: not currently evaluated (ISAG/AVCG, per OMIA).
- Discovery: the locus was mapped to ECA9 by linkage to HTG8 and HTG4 (Bailey et al., 1997); the causal deletion was identified by Shin et al. (1997).
- Mechanism: DNA-PKcs carries out the rejoining step of V(D)J recombination, which lymphocytes need to assemble their antigen receptors. Homozygotes lack functional V(D)J recombination (Wiler et al., 1995) and develop no functional adaptive immune system.
- Inheritance: autosomal recessive (OMIA code R; Perryman and Torbeck, 1980).
- Penetrance / expressivity: homozygotes die within the first months of life. Heterozygotes are immunologically normal; carriers were over-represented among Arabians with sarcoids (18.6% of 102) and with tumours overall (13.9%, versus 8.7% of 508 tumour-free Arabians), with no association with melanoma (Ding et al., 2002).
- Breeds with documented carriers or cases: Arabian (OMIA variant record) and part-bred Arabians, including Arab-Barbs and Anglo-Arabs. A SCID phenotype has been reported in a Caspian filly (Larson et al., 2011).
- Allele / carrier frequencies: all figures are carrier frequencies. USA: 8.4% of 250 randomly sampled Arabians (Bernoco and Bailey, 1998); about 8.7% of 508 tumour-free Arabians (Ding et al., 2002). UK: 3/106 (2.8%), national estimate 1 to 5% (Swinburne et al., 1999). South Africa: 6.4% of the 2004/5 purebred Arabian foal crop (n=203) and 3.4% of the 2009/10 crop (n=197), after testing became available (Tarr et al., 2014). Egypt: 0 of 103 horses, including 33 randomly sampled Arabians (AbouEl Ela et al., 2018). Earlier estimates of 25 to 30% came from horses already suspected of carrying the disease and are regarded as far too high. Screening studies have also been published from Morocco, Poland and the wider Middle East and North Africa.
- Clinical / diagnostic notes for veterinarians: in an Arabian foal with recurrent infections, the main differential is failure of passive transfer of colostral immunity, which this test does not assess. LFS foals do not show immunodeficiency.
Key references:
- Shin EK, Perryman LE, Meek K (1997). A kinase-negative mutation of DNA-PKcs in equine SCID results in defective coding and signal joint formation. J Immunol 158:3565-3569. PMID 9103416.
- Wiler R, Leber R, Moore BB, VanDyk LF, Perryman LE, Meek K (1995). Equine severe combined immunodeficiency: a defect in V(D)J recombination and DNA-dependent protein kinase activity. Proc Natl Acad Sci USA 92:11485-11489.
- Bailey E, Reid RC, Skow LC, Mathiason K, Lear TL, McGuire TC (1997). Linkage of the gene for equine combined immunodeficiency disease to microsatellite markers HTG8 and HTG4. Anim Genet 28:268-273.
- Bernoco D, Bailey E (1998). Frequency of the SCID gene among Arabian horses in the USA. Anim Genet 29:41-42.
- Swinburne J, Lockhart L, Scott M, Binns MM (1999). Estimation of the prevalence of severe combined immunodeficiency disease in UK Arab horses as determined by a DNA-based test. Vet Rec 145:22-23.
- Ding Q, Bramble L, Yuzbasiyan-Gurkan V, Bell T, Meek K (2002). DNA-PKcs mutations in dogs and horses: allele frequency and association with neoplasia. Gene 283:263-269. doi:10.1016/s0378-1119(01)00880-0.
- Tarr CJ, Thompson PN, Guthrie AJ, Harper CK (2014). The carrier prevalence of severe combined immunodeficiency, lavender foal syndrome and cerebellar abiotrophy in Arabian horses in South Africa. Equine Vet J 46:512-514. doi:10.1111/evj.12177.
- AbouEl Ela NA, El-Nesr KA, Ahmed HA, Brooks SA (2018). Molecular detection of severe combined immunodeficiency disorder in Arabian horses in Egypt. J Equine Vet Sci 68:55-58. doi:10.1016/j.jevs.2018.05.210.