Top 5 Feline Genetic Conditions
Zuku's Feline Genetic Conditions To Know For NAVLE® Success:
1. Hypertrophic cardiomyopathy (HCM) Classic case: Maine coon, ragdoll, Persion, sphynx, Norwegian forest cat, domestic shorthair Signs can range from asymptomatic to congestive left heart failure (tachypnea, dyspnea), thromboembolic disease (cyanotic nail beds, paraplegia) to sudden death Click here to see a gross image of HCM Dx: Radiography: Lateral thoracic radiograph - note increased sternal contact of the heart Normal or cardiomegaly as seen with HCM Dilated left atrium (classic valentine shape on DV) Pulmonary edema, congestion Pleural effusion Echocardiography (M-mode): Atrial dilation Left ventricular wall thickening and papillary muscle hypertrophy Systolic anterior motion of mitral valve if obstructive cardiomyopathy Genetic testing Rx: Only if symptomatic Color doppler echocardiography (right Oxygen parasternal, long axis) of HCM in a Furosemide domestic shorthair cat. There is septal ACE inhibitor thickening and mitral regurgitation Pearls: Autosomal dominant with incomplete penetrance in Maine coon and ragdoll Mutation affects cardiac myosin binding C gene (MYBPC3) For more details on HCM, see Top 20 Feline Diagnoses: Part 4, #16
2. Polycystic kidney disease (PKD) Classic case: Persian, exotic, Himalayan, ragdoll, or British shorthair Variable: Asymptomatic to signs of chronic renal failure (polyuria/polydipsia, lethargy, weight loss, vomiting) at around 3-10 yrs of age Hypertension is uncommon Dx: Azotemia Ultrasonography: Presence of a single to multiple cysts Genetic testing Rx: Supportive for renal failure if necessary Pearls: Autosomal dominant mutation of the PKD1 gene results in abnormal production of polycystin proteins Abnormal dilations of renal tubules cause the cysts
3. Sacrocaudal dysgenesis Classic case: Manx Urinary or fecal incontinence +/- Pelvic limb weakness, bunny-hopping gait Click here to see a radiograph of sacrocaudal dysgenesis in a Manx cat Dx: Physical exam Polycystic kidney (human) Abdominal radiographs may Sacrocaudal dysgenesis occurs in show megacolon Manx cats Spinal radiographs, CT, MRI showing malformation of the sacrum Spina bifida may be associated with sacrocaudal dysgenesis Rx: Bladder management Pearls: Autosomal dominant of the Manx gene, M All Manx cats are heterozygous Mm and MM is lethal; mm cats are tailed and are therefore not Manx Not all Manx cats have sacrocaudal dysgenesis; there may be a modifying gene or environmental factor that affects expression of the gene causing the disorder Poor prognosis for recovery of normal function
4. Polydactyly Classic case: Greater than 5 digits on a limb Preaxial polydactyly (= extra digit(s) on medial paw) is most frequent Lateral polydactyly (= extra digit(s) on lateral paw) is uncommon Dx: Physical exam Rx: Keep claws trimmed Claws may curve around and puncture the pad, requiring amputation in some cases Preaxial polydactyly Click here to see a video of clipping an ingrown nail Pearls: Autosomal dominant with variable expressivity Extra digits can be prone to trauma Also known as "Hemingway mutant" because Ernest Hemingway kept many of these cats at his home in Key West, FL Polydactyly in occurs in other animals, too (horses, ruminants, pigs) Click here to see a radiograph of a calf with polydactyly
5. Hereditary deafness Classic case: White cat with blue eyes that is unresponsive to auditory stimuli Dx: No response to whistles and loud noises in exam room (reactions to vibrations from exam table may give false impression of ability to hear) Brainstem auditory evoked response (BAER) necessary to detect unilateral deafness Rx: None available Do not allow outdoors Pearls: Autosomal dominant (epistatic white masking Ernest Hemingway famously kept gene, W) many polyldactyl cats as pets Caused by degeneration of the stria vascularis (necessary for endolymph production and the endocochlear potential required for cochlear White cats have a high incidence of hair cell function) at 1-3 deafness wks of age Similar to Waardenburg syndrome in humans which is charactierised by hypomelanosis and deafness The vestibular apparatus is unaffected
Images courtesy of Keith Kissel (odd-eyed cat), Icebooter (blue-eyed white cat), Ed Uthman (polycystic kidney), Ventus55 (polydactyly), Kalumet (echocardiography), Dr Terri Defrancesco (radiograph of hypertrophic cardiomyopathy), Michelle Weigold (Manx), Heikki Siltala (Scottish fold), and Desaix83 (sphynx). © 2020 ZukuReview.com - All Rights Reserved