Genetic Disorders Flashcards
Describe entropion.
Common in lambs and kids of most breeds.
Often lower lid turning inward with blepharospasm and photophobia potentially becoming ulcerations.
Fix by placing a suture or surgical staple in lower eyelid to anchor lid
Describe beta mannosidosis, including breeds, clinical signs, and heritability.
Nubian goats
Intention tremors and difficulty of inability of newborns to stand. Characteristic flexion of carpal joint and hyperextension of pastern. Deaf with other musculoskeletal deformities such as a domed skull, small narrow muzzle, enophthalmos, and depressed nasal bridge.
Autosomal recessive lysosomal storage disease. Carriers identified by plasma measurements of beta mannosidase
Describe congential myotonia.
Inherited autosomal dominant disease in goats. ‘Fainting’ goats
Affects voluntary striated muscle. Transient spasms of skeletal musculature brought about by visual, tactile, or auditory stimuli. Contractions sustained for up to 1 minute. Exhibit signs by 6 weeks of age, males more severe signs than females.
Describe polled intersex goats.
Western European goat breeds (Alpine, Saanen, Toggenburg) have genetic relationship between polled phenotype and intersex characteristics.
Gene deletion on chromosome 1 affects regulation of horn bud and fetal ovarian development. Genetically female animals with masculine characteristics such as enlarged clitoris, decreased anogenital distance, and muscular neck development.
Not fertile, testosterone production results in characteristic male odor and aggressive behavior.
What genetic diseases are found in the following breeds?
Holsteins, Angus, Brown Swiss, Beef, Dairy
Holstein - Syndactyly and complex vertebral malformations
Angus - Arthrogryposis multiplex
Brown Swiss - Progressive degenerative myeloencephalopathy (weaver)
Beef - Lysosomal storage diseases such as alpha-mannosidosis
Dairy - Inherited periodic spasticity (crampy syndrome)
Describe congenital erthyropoietic porphyria.
Rare autosomal disease of cattle in Holsteins, Herefords, and Shorthorns. Heterozygotes may have milder signs.
Low activity of essential enzyme uroporphyrinogen III synthase
Reddish-brown discoloration of teeth and bones, discolored urine, general weakness and failure to thrive, and photosensitization and photophobia. Bones fragile. Regenerative anemia due to shortened life span of RBCs.
Porphyrins excreted in various amounts in urine and fluoresce under a Woods lamp.
Describe congenital dyshormonogenetic goiter.
Defect in the synthesis of thyroid hormone in Merino sheep and goats. Autosomal recessive in Corriedale, Dorset Horn, Merino, and Romney sheep and Saanen dwarf goats
Born with enlarged thyroid gland. Silky appearance to wool and high mortality. Edema, bowing of legs, and facial abnormalities. Immaturity of lungs at birth causes neonatal resp distress and results in dyspnea and resp failure.
Describe hereditary chondrodysplasia.
AKA Spider lamb syndrome. Inherited, often lethal musculoskeletal disorder in Suffolk and Hampshire sheep.
Severely affected lambs due shortly after birth. Those that survive develop angular limb deformities, scoliosis, and facial deformities. Muscle atrophy common.
Diagnosis based on clinical signs, similar to Marfan syndrome in humans.
Long-term survival rare, treatment unsuccessful.
What genetic disease to Suffolk and Coopworth-Romney sheep have?
Gangliosidosis.
What genetic disease do polled Dorset sheep have?
Globoid cell leukodystrophy, or Krabbe’s disease.
What sheep have ceroid lipofuscinosis?
South Hampshire, Swedish Landrace, and Ramboullet
What genetic conditions are Suffolk sheep predisposed to?
Neuroaxonal dystrophy
What genetic condition to Merino and Charollais sheep develop?
Primary cerebellar degeneration.
