Genetic Diseases of German Shorthaired Pointer Dogs

1. Genetic Diseases of German Shorthaired Pointer Dogs James C. Zgoda, M.S., D.V.M. Otterkill Animal Hospital Campbell Hall, NY Sleepy Hollow GSHP Club July 21, 2010

2. PHENOTYPE • The physical appearance of an animal • Subjective opinion • Outward expression of genetic makeup

3. Phenotypic Testing • Conformation Shows/Testing • Meet Breed Standard • Screening Organizations • OFA • PennHip • CERF

4. GENOTYPE • Genetic makeup of animal • Not all genes are expressed • Many factors are involved

5. Genetic Testing • Screen for actual presence of Gene or Gene marker • Need to be verified for each breed • Proprietary technique • Results in Many Testing Centers • Cheek swabs or blood used to collect DNA • Must minimize contamination

6. Terminology • Hereditary/Inherited/ Heritable • Traits are passed on from generation to generation via genes • Congenital • Traits present at birth but may not be hereditary, e.g. birth defects

7. Phenotypic Testing • Advantages • It’s what we’re all used to • Has been used for long time • Breed standards • Disadvantages • Harmful traits may be passed along with good ones • May take long time for problem to become apparent • Screening tests are subjective

8. Genotypic Testing • Advantages • Results can be known at very early age • Ease of testing • Screening tests are objective • Definitively know genetic status • Disadvantages • Multiple Laboratory sites • Tests limited • Must be verified for each specific breed

9. Gene Expression Dominant Gene will be expressed if only 1 copy of gene present Recessive Gene will be expressed only if 2 copies of gene are present Incomplete/variable expression Gene may not be fully expressed as expected Results in “sliding scale” of traits

10. The Old Punnett Square

11. GSHP Inherited Diseases • Hip/Elbow Dysplasia • AcralMultilation Syndrome • Aortic Stenosis • Cataracts • Entropion • Eversion of the cartilage of the third Eyelid • GM2 Gangliosidosis • Hemivertabra • Lymphedema • LupoidDermatosis • Progressive Retinal Atrophy • Cone Disease • Von Willebrand’s Disease • XX Sex reversal

12. Hip Dysplasia Mutliple components affecting tightness of hip joints May not become apparent until much later in life Testing methods are primarily subjective -Two cleared parents are no guarantee of clear offspring -Multiple genes are involved -Genetic testing will likely never be possible

13. OFA Testing -Prelims can be done early but may not correlate with adult scores -certification not done until 2 years of age -Completely subjective testing -Films read by three boarded radiologists -Open submission system leading to skewed results -Useful tool but limited progress on eliminating HD has been achieved Results in Fail, Fair, Good Excellent Ratings

14. PennHip • -Certification can be done and is accurate at 4 months. Correlates with later scores. • -Objective measurement of hip laxity • Veterinarian must be certified • Closed submission system • Evidence that its use can decrease incidence of HD • Result is DI – Distraction Index

15. Pennhip Views Compression Film Distraction Film

16. Elbow dysplasia • Developmental defect in formation • of elbow joint • One or more components • UnunitedAnconeal Process • Fragmented Coronoid Process • Results in instability, pain, lameness • and arthritis • Usually apparent in young dog 6-8 months • Screening by veterinarian • OFA screening system • Treated surgically • Polygenic inheritence

17. Acral Mutilation Syndrome • May begin as early as 3-5 months of age • Treatment is symptomatic • Believed to be Autosomal recessive • Dogs lose sensation in feet • Leads to chronic licking, mutilation, infection • No testing currently available

18. Aortic Stenosis • Narrowing of Outflow tract • Can result in failure • Murmur detected at any age • Echocardiogram is definitive • Treatment is symptomatic • Surgery in extreme cases • Screening • Auscultation • Cardiac Certification • Believed to be Autosomal • Dominant • No genetic test

19. Cataracts • Opacity in lens • Most are inherited but some are s • secondary to diseases • Juvenile cataracts present early • Others not apparent until later • Screening by veterinarian • Or Ophthalmologist • Annual CERF testing since may • not show up until later in life • Unknown mode of inheritence • No genetic testing currently available

20. Entropion • Inward rolling of eyelid usually lower • One or Both eyes affected • Results in corneal irritation, pain • discharge • Usually Apparent early • Screening by Veterinarian • Corrected surgically • Polygenic inheritance • No Genetic testing

21. Eversion of Cartilage of Third Eyelid • Rolling in or out of cartilage along • margin of third eyelid • Results in chronic irritation • Screening by veterinarian • Surgically removed • Unknown inheritance • No genetic test

22. GM2 Gangliosidosis • Storage disease of molecules which lead to nerve damage • Severe neurologic signs • Apparent at 6-12 months of age • Often have “Coarse” facial appearance • Screening by veterinarian • Treatment is euthanasia • Believed to be autosomal recessive • No genetic test for GSHPs

23. Hemivertebra • Abnormal development of one • or more vertebra • May or may not cause neurologic • signs • May be incidental finding • No treatment unless compressing • spinal chord • Screening by veterinarian • Autosomal recessive • No genetic testing

24. Lymphedema • Abnormal or obstruction of lymph flow • Results in severe swelling • , usually hind legs first • Treatment may or may not be needed • Screening by veterinarian • Autosomal Dominant • Abnormal or obstruction of Lymph flow • No genetic test

25. LupoidDermatosis • Autoimmune disease • Inflamed, crusty, itchy skin • Usually begins at 6 months of age • Begins on face and legs • May spread to entire body • Biopsy is definitive • Variable response to treatment with • immunosuppressive drugs

26. LupoidDermatosis • Funded research ongoing at Univ Penn. • Genetic Marker test available • May be unique to GSHP • Commercial testing may be available in near future

27. Progressive Retinal Atrophy -PRA • Progressive degeneration • of rods and cones • Night blindness at age 2-5 • Progresses to complete • blindness • Annual CERF testing • No treatment available • Genetic tests for some breeds • Not GHSPs • Autosomal recessive

28. Cone Degeneration - CD • Degeneration of Cones only • Day blindess can begin as • early as 8-12 weeks • Vision normal at night • No treatment • CERF testing • Autosomal recessive • Genetic Test Available!! • Optigen

29. Cone Disease

30. Von Willebrand’s Disease • Lack of vWF factor in blood • Leads to prolonged bleeding • May or may not be significant • Can be managed if known • Screening as early as 6 weeks • Autosomal recessive with incomplete expression • Reported as factor level • Genetic Test for some breeds, not GSHP

31. XX Sex Reversal • Form of hermaphrodism • Carries both ovaries and testicle • May have abnormal external genitalia • Screening by veterinarian • Autosomal Recessive

32. NOW WHAT? How do we put this knowledge to use to improve our breeding program?

33. Recommendations • Develop stringent screening program and stick to it! • Breed only cleared animals to cleared animals • Screen as early as feasible to determine if dog should be retained in program • Don’t ever become discouraged. Genetics is always a roll of the dice we’re just beginning to understand • Participate in breed studies when possible

34. GSPCA Recommendations • Certify for Hip and Elbow Dysplasia through OFA or Pennhip • Congenital Cardiac Clearance by veterinary Cardiologist • Annual CERF exams until age 6 then every two years • Cone degeneration testing through Optigen

35. Our Goal Happy and Healthy German Shorthaired Pointers!!