2015
• During 2015 there were several cases of HC and all of these owners have been contacted and swab kits dispatched. Our thanks go to all concerned who have sent their dog’s DNA plus relevant documentation to the AHT
• The AHT also asked that we highlight their request for continued sample contributions from any Miniature Schnauzer affected by any form of cataract in both eyes, especially those that can provide accompanying (KC/BVA/ISDS) eye examinations and pedigree information
• They also remain equally keen to receive DNA samples from Miniature Schnauzers with clear eye examinations and over the age of 6 years, for use as controls in their continuing studies.
• The AHT emphasise that they do not release details of dogs or owners to any outside organisation, therefore samples can be submitted to them in absolute confidence without the need for anonymity
The AHT & JMSEF send sincere thanks to all of those that have contributed samples of DNA and information on affected dogs and their relatives. We can only achieve these goals if you continue to support testing, submission of DNA samples, reporting and raising funds for future research. For swab kits and / or further information, please contact Sue McGrann, isaura@ewerbywaithe.freeserve.co.uk
The following figures were issued by the BVA for 2014:
• CHC: From 1053 litters KC registered, 671 litters were screened (63.7%) and 3 litters had affected (CHC) puppies (3 pups of the 19 in those 3 litters)
• HC: 973 dogs were eye tested, resulting in 7 affected (HC). This was the highest figure since 2011. All owners were contacted and swab kits sent
• Remember that DNA is required for CHC research. Samples from dogs affected by CHC and their unaffected littermates or parents are just as important to the AHT research as the actual CHC cases
2013
Congenital Hereditary Cataract (CHC)
The AHT’s recent initial research, (Whole Genome Scan) suggested that CHC in the Miniature Schnauzer is not a simple recessive condition and so the BVA Eye Panel Working Party have been made aware of this.
The AHT state that if it is dominant, of course, only one of the parents needs to be a carrier, but until we understand at least some of the genetic architecture underlying CHC (which we very much hope will be revealed by a second genome scan) and because our dataset of 16 cases and 16 controls was small, it is impossible to entirely exclude it being recessive.
Source: AHT May 2013
Hereditary Cataract (HC)
There’s a strong chance HC is complex – so there is more than one susceptibility gene in a given breed. That’s what our current research is suggesting in other breeds.
To be clear, HC could be caused by either:
a) more than one gene, either of which could come from either parent
b) a problem gene from both parents + another problem gene from one
or both
Source: AHT May 2013
Recomendations
For both conditions, the safest route forward for caring breeders at present, is they continue to be guided by current ‘best practice’ recommendations:
- If a dog is certified as ‘affected’, then both parents should be viewed as ‘carriers’. The mating should not be repeated.
- The ‘affected’ should not be bred from.
- As both parents are viewed as ‘carriers’, in an ideal world, they should be taken out of breeding programmes. However, great care must be taken if used in any on-going breeding plan. The breeder/stud dog owner must make every effort to ensure the puppy-seeker / bitch owner is fully aware of these current ‘best practice’ guidelines.
- Similarly, great care must be taken when using siblings of the ‘affected’, although, in an ideal world these should not be bred from. Here too, the breeder/stud dog owner must make every effort to ensure the puppy-seeker / bitch owner is fully aware of these current ‘best practice’ guidelines.
- In an ideal world, owners of all other progeny of the sire or dam should be advised of the test result, so that they too can take great care in planning any breeding programme.