In a recently published article titled “Dwarfism with joint laxity in Friesian horses is associated with a splice site mutation in B4GALT7”, a group of researchers indicated that they had “localized the genetic cause of the dwarfism by a genome-wide approach to a 3 Mb region on the p-arm of equine chromosome 14.
The DNA of two dwarfs and one control Friesian horse was sequenced completely, and researchers identified the missense mutation that cosegregated with the phenotype in all Friesians analyzed. They then observed that a similar mutation in humans is associated with Ehlers-Danlos syndrome progeroid type 1 and Larsen of Reunion Island syndrome. Growth retardation and ligamentous laxity are common manifestations of these syndromes. They concluded that breeding with carriers can be prevented by screening breeding stock for the B4GALT7 mutation, and the dwarfism trait could thus be eliminated from the breed.
Article: Leegwater et al. Dwarfism with joint laxity in Friesian horses is associated with a splice
site mutation in B$GALT7. BMC Genomics (2016) 17:839. DOI 10.1 186/s12864-016- 3186-0.