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Dwarfism ( Chondrodysplasia ) ACAN
Test number: 8548
Gene: d
Price: £ 66.00 (including VAT)
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Breeds
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Miniature Horse
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Shetland Pony
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The Disease |
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Chondrodysplasia-like dwarfism in Miniature horses and Shetland ponies is a disproportionate type of dwarfism which involves malformations of the cartilage and subsequent maturation to bone during foetal development and subsequent growth of the individual during sexual maturation. This type of dwarfism is not considered a desirable trait due to its association with serious health issues including breathing problems, malformed mouth that causes eating difficulties, and abnormal bone growth leading to chronic health issues.
Disproportionate dwarfism involves the shortening and malformation of all the long bones of the body and causes abnormal growth of the other bones within the body such as the skill.
A recent research by John Eberth and Ernie Bailey identified four mutations in the ACAN gene which are associated with Chondrodysplasia-like dwarfism. The four mutations are termed D1, D2, D3 and D4. |
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Trait of Inheritance |
The disease follows an autosomal recessive trait of inheritance and therefore a horse with one copy of the mutation : N/D1, N/D2, N/D3 or N/D4 are clinically normal and have a normal appearance but they are genetically carriers, a carrier will pass the mutation to its offspring with a 50% probability.
The D1 mutation is considered lethal if combined with any other mutation: D1/D1, D1/D2, D1/D3 and D1/D4. These horses will die in the womb and will consequently be aborted or reabsorbed.
Dwarf horses have two copies of any mutation except D1, and therefore will have one of the following genotypes: D2/D2, D2/D3, D2/D4, D3/D4, and all have similar symptoms of dwarfism, which vary from mild to severe.
It is worth noting that the genotypes D3/D3 and D4/D4 have unknown effects, as no samples with these genotypes have been found so far. |
Inheritance : AUTOSOMAL
RECESSIVE
trait
Sire
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Dam
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Offspring
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clear
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clear
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100% clear
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clear
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carrier
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50% clear + 50%
carriers
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clear
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affected
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100% carriers
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carrier
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clear
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50% clear + 50%
carriers
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carrier
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carrier
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25% clear + 25% affected
+ 50% carriers
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carrier
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affected
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50% carriers + 50%
affected
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affected
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clear
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100% carriers
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affected
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carrier
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50% carriers + 50%
affected
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affected
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affected
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100% affected
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Clear
Genotype: N / N [ Homozygous normal ]
The horse is noncarrier of the mutant gene.
It is very unlikely that the horse will develop Dwarfism ( Chondrodysplasia ) ACAN. The horse will never pass the mutation to its offspring, and therefore it can be bred to any other horse.
Carrier
Genotype: N / d [ Heterozygous ]
The horse carries one copy of the mutant gene and one
copy of the normal gene.
The horse is clinically normal and has a normal appearance but it is genetically a carrier, a carrier will pass the mutation to its offspring with a 50% probability.
Affected
Genotype: d / d [ Homozygous mutant ]
The horse carries two copies of the mutant gene and
therefore it will pass the mutant gene to its entire offspring.
The horse will be dwarf ( Chondrodysplasia ) and will pass the mutant gene to its entire offspring
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Sample Requirements |
Hair Sample from mane with roots (approx 30 hairs) or 1 ml whole blood in EDTA tube.
How to obtain a viable hair sample
Pull around 30 hairs from the mane of the horse with the roots (in faols hair from the tail maybe taken). Wrap the hairs around your finger or a comb, as close as possible to the skin to ensure you obtain the hair roots. Keep dry, put in a bag, label the bag with the horse name, test (s) required. Place in an envelope and send back to us together with the order form. Broken or cut off hair will not be accepted.
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Parameters |
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D1, D2, D3, D4
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Price
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£ 66.00 (including VAT)
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