Hoof Wall Separation Disease (hwsd)

Hoof wall separation disease is characterized by separation and breakage of the dorsal hoof wall extending up from the sole. Affected ponies begin showing symptoms at less than 6 months of age, and often develop chronic laminitis. Frequent hoof trimming and glue on shoes can help manage the condition. Hoof wall separation disease is an autosomal recessive disorder, thus a pony must inherit two copies (HWSD/HWSD) to show symptoms. Ponies with only one allele (HWSD/N) are known as carriers due to their ability to produce affected offspring.

SERPINB11 is a serine protease inhibitor of unknown function. In normal horses, it is highly expressed in the corony band. However, the insertion associated with HWSD results in a premature stop codon, resulting in an incomplete protein and greatly decreased expression.

Publications

Finno CJ et al., “SERPINB11 frameshift variant associated with novel hoof specific phenotype in Connemara ponies.” (2015) PLoS Genet. 11: e1005122.  PMID: 25875171