Thursday, 18 July 2013

HWSS research has been officially presented to the world.

The team from Bannasch Laboratory were involved  in the recent 10th International Equine Genome Mapping Workshop  held  10-13 July 2013 at the Biotechnology Centre of Azores from the University of Azores. 

The First International Equine Gene Mapping Workshop sponsored by the Dorothy Russell Havemeyer Foundation (DRHF) was conducted in 1995 in Lexington, Kentucky. Since then, a series of horse genome workshops were conducted by the DRHF every two years (San Diego, California; 1997; Uppsala, Sweden; 1999; Brisbane, Australia; 2001; Kreuger Park, South Africa; 2003; Newbridge, Ireland; 2005; Tahoe City, California; 2007; Ickworth, Suffolk, United Kingdom; 2009; Chaska, Minnesota; 2011).

Over 200 scientists from 20 countries around the world have been participating in these workshops, sharing ideas and resources, collaborating and creating a common genomics framework.

The Bannasch submission is as follows:

10th Dorothy Russell Havemeyer Foundation International Equine Genome Mapping Workshop Abstract
A successful genome wide association for Connemara Hoof Wall Separation Syndrome using the equine Illumina 74K beadchip
Danika Bannasch, Carrie Finno, Carlynn Stevens, Amy Young, Sheila Ramsay
A syndrome has been described in Connemara foals characterized by severe separation of the hoof wall during the first year of life.  Clinical signs of HWSS occur when the weight-bearing borders of the hoof wall break away from the underlying structure, leaving the pony to bear weight on the sole of the hoof and unfit for riding.  Initial pedigree research has revealed a likely hereditary component to the disease with an apparent autosomal recessive mode of inheritance.   DNA samples, pedigrees and photographs were collected from Connemara ponies from around the world.  Within a year, 15 affected individuals and 315 controls were sampled.  Twelve cases and 24 controls were genotyped on the Illumina Equine 74K beadchip.  Based on our results, 12 affected and 24 unaffected cases provided significant power to identify a strong, genome-wide significant, candidate region of association (p raw 6.9 X 10-11, p genome 2.6 X 10-5).  Three additional affected foals and 5 obligate carriers were subsequently genotyped.  A region of homozygosity of 1.8 Mb was identified in all 15 affected foals consistent with an autosomal recessive mode of inheritance. Next generation sequence data from affected ponies and controls across the region will be analyzed for mutations and the results reported at the meeting.

The take home message from the information in the above abstract is that:

  • There is NO DOUBT WHATSOEVER that HWSS is genetic in origin.  
  • There is NO WAY that the above abstract would have been accepted for this workshop if the work being presented  was not proven beyond all doubt.
  • HWSS is NOT the result of 'mineral imbalance', any other environmental challenge or lack of care of the part of owners of affected ponies.
  • HWSS is the result of mating two ponies who carry a genetic mutation.

Denial that the cause of this condition is genetic is not going to make the problem disappear; indeed based on present trends the incidence of HWSS in the Connemara pony population is set to increase. 
A population genetics study presently underway, indicates that this is especially so in Ireland; a direct result of overuse of certain stallions both historically and in the present.