Recent research has revealed that, in addition to the four known ACAN mutations, another mutation can cause dwarfism in miniature horses, the so-called ACAN D5 mutation.
It is now possible to test for the new D5 mutation as an additional option through CombiBreed. There are now two test variants available:
• P306: The ACAN dwarfism test for D1, D2, D3 IMPROVED, and D4 for €47.50 excluding VAT
• P380: The ACAN dwarfism test for D1, D2, D3 IMPROVED, D4, and D5 for €52.50 excluding VAT
DNA tests for ACAN
Dwarfism in (miniature) horses is an autosomal recessive condition, where horses that possess two of the four previously known ACAN variants (D1, D2, D3*, and/or D4) always exhibit dwarfism. This means that both horses that are homozygous (affected) and those that are carriers of two different ACAN variants will display the dwarfism phenotype.
New findings
In recent research, eight horses with a dwarfism phenotype were found to have only one allele for D2, D3*, or D4. This suggests that there are additional ACAN alleles that cause dwarfism. From this research, the D5 variant (g.95258999 C>T) emerged alongside the already known dwarfism variants D1-D4 and the Brazil haplotype. This variant can now be tested in addition to the previously known ACAN variants.
More information is available in the publication: MOLECULAR GENETIC STUDIES OF HORSES, ESPECIALLY WITH REFERENCE TO AGGR” by John Edmund Eberth (uky.edu)