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

PHENOTYPE

Phenotypic Testing Conformation Shows/Testing ▫ Meet Breed Standard Screening Organizations ▫ OFA ▫ PennHip ▫ CERF

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

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

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

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

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

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

The Old Punnett Square

GSHP Inherited Diseases Hip/Elbow Dysplasia Acral Multilation Syndrome Aortic Stenosis Cataracts Entropion Eversion of the cartilage of the third Eyelid GM2 Gangliosidosis Hemivertabra Lymphedema Lupoid Dermatosis Progressive Retinal Atrophy Cone Disease Von Willebrand’s Disease XX Sex reversal

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

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

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

Pennhip Views Compression FilmDistraction Film

Elbow dysplasia Developmental defect in formation of elbow joint One or more components Ununited Anconeal 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

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

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

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

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

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

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

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

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

Lupoid Dermatosis 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

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

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

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

Cone Disease

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

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

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

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

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

Our Goal Happy and Healthy German Shorthaired Pointers!!