WCVD 2020 - Diseases of Keratinization Flashcards
X-linked hypohidrotic ectodermal dysplasia results from a mutation in what gene?
ectodysplasin-A (EDA) gene
Histopathologic features of hereditary nasal parakeratosis
marked parakeratosis with serum lakes between cell layers of the nose
DDX for canine acne
demodicosis, dermatophytosis, contact hypersensitivity
T/F: Acitrentin can upregulate the activity of ABCA6 to partially compensate for a lack of ABCA12.
TRUE
Jack Russell Terriers have a mutation in the gene that encodes for what? Epidermolytic or NON-epidermolytic ichthyosis? Mode of inheritance
transglutaminase-1; NON-epidermolytic; Autosomal Recessive
Ichthyosis in Cavalier King Charles Spaniels results from a mutation in what gene? What is clinical presentation?
FAM83H; dry eye and frizzy haircoat, dorsal scaling, footpad hyperkeratosis, and deformed claws that may slough (Congenital Keratoconjunctivitis Sicca and Ichthyosform Dermatosis)
Equine Linear Keratosis has been reported in what breed?
Quarter Horses
Mutations in the genes that encode for what structures result in epidermolytic ichthyosis?
keratins
T/F: The footpads, claws, hair and teeth of Norfolk terriers with mutations in keratin 10 are normal.
TRUE
Histopathologic features of epidermolytic ichthyosis?
vacuoles and lysis of keratinocytes in stratum spinosum and stratum granulosum, hypergranulosis, hyperkeratosis
Great Dane ichthyosis results from a mutation in what gene?
SLC27A4 gene found on chromosome 9 –> affects production of fatty acid transport protein 4 (FATP4), an acyl-CoA synthetase required for normal permeability barrier function
What does the gene patatin-like phospholipase-1 encode for? Mutations result in what disease?
acylceramide, role in glycerophospholipid metabolism and cutaneous barrier function; Golden retriever ichthyosis (rough haircoat and scaling)
Which keratins are present in the upper layers of the epidermis?
keratins 1, 2, 10
Mutations in the genes that encode for what structures result in NON-epidermolytic ichthyosis?
lipids, non-keratin proteins, or desquamation
American bulldog ichthyosis is due to a mutation in what gene? Epidermolytic or NON-epidermolytic? Mode of inheritance?
NIPAL4 (nuclear interaction partner of ALK-like domain containing 4); non-epidermolytic; autosomal recessive
Hairlessness of the American hairless terrier is due to what genetic mutation?
frameshift deletion of serum glucocorticoid regulated kinase family member 3 gene (SGK3)
Genetic mutation responsible for hereditary nasal parakeratosis?
SUV39H2 gene
T/F: Cattle with bovine hereditary zinc deficiency improve with zinc supplementation.
TRUE
T/F: Supplementation of aciretin to pregnant sows with a mutation in the ABCA12 gene resulted in improved phenotype and longer survival.
TRUE
T/F: American hairless terriers are born hairless.
False - mutation is in a gene that is involved in postnatal hair follicle development - born with a thin coat of hair that is lost within the first months of life
DDX for Schnauzer Comedo syndrome
demodicosis, dermatophytosis, bacterial folliculitis, hyperadrenocorticism, hypothyroidism, follicular dystrophy
Flechvieh cattle have an autosomal recessive cornification disorder due to a mutation of what gene?
PLD4 – phospholipase encoding gene
Naked foal syndrome has been reported in what breed of horses, caused by a mutation in the ST14 gene? What is the function of the ST14 gene?
Akhal-Teke horses; ST14 –> serine protease involved in epidermal development
Mutation in aspartic peptidase, retroviral-like 1 results in what changes? What clinical disease?
faulty processing of profilaggrin to filaggrin –> wrinkled, dry, rough skin due to lack of aggregation of keratin intermediate filaments and deficiency of natural moisturizing factor; German shepherd dog ichthyosis
T/F: The footpads, claws, hair and teeth of Jack Russell Terriers with mutations in transglutaminase-1 are normal.
False – footpad hyperkeratosis, onchyomalacia is present
Hereditary nasal parakeratosis has been reported in what breeds of dog?
Labs and greyhounds
T/F: Chinese crested dogs are homozygous for the mutation of forkhead box transcription factor 13 (FOX13), resulting in the hairless phenotype.
False - is an autosomal DOMINANT inheritance pattern, homozygous mutation is LETHAL
Bovine hereditary zinc deficiency has been reported in what breeds? Mode of inheritance?
Black pied Fresian cattle, Holstein-Fresians, shorthorns, Angus; Autosomal recessive
Familial paw pad hyperkeratosis due to a mutation in the FAM83G has been reported in what breeds?
Dromfohrlander, Irish terriers, Dogues de Bordeaux
T/F: Bull terriers with lethal acrodermatitis improve with zinc supplementation.
FALSE
X-linked hypohidrotic ectodermal dysplasia has been reported most commonly in what breeds?
dachshunds, GSD, poodles, mixed breeds
Norfolk terriers have a mutation in the gene that encodes for what? Is this an epidermolytic or NON-epidermolytic ichthyosis? Mode of inheritance?
Keratin 10; Epidermolytic; Autosomal Recessive
What breed of cattle have been reported to have ichthyosis fetalis?
Chianina & Shorthorn cattle
What breeds are reported to have epidermolytic ichthyosis?
Norfolk terriers, Rhodesian ridgebacks, Labs, CKCS
German shepherd dog ichthyosis is due to a mutation in what gene? Epidermolytic or NON-epidermolytic? Mode of inheritance?
aspartic peptidase retroviral-like 1 (ASPRV1); non-epidermolytic; autosomal recessive
T/F: Flechvieh cattle with the autosomal recessive cornification disorder due to a mutation in PLD4 improve with zinc supplementation.
FALSE
Lethal acrodermatitis of bull terriers is due to a mutation in what gene? What is its function?
MKLN1 gene –> encodes intracellular protein muskelin-1 –> functions in cell adhesion and intracellular transport processes
Hairlessness in Chinese crested, Mexican xoloitcuintle and Peruvian Inca orchid dogs is due to a mutation in what gene? What does this gene regulate?
forkhead box transcription factor 13 (FOX13); regulates ectodermal development, postnatal hair growth and hair regeneration
What are characteristic features of ichthyosis fetalis?
microtia and eversion of skin of the lips and eyelids
What are the terminal breakdown products of filaggrin that are the main components of “natural moisturizing factor”?
pyrrolidone carboxylic acid and urocanic acid
T/F: Pharoah hounds with lethal acrodermatitis improve with zinc supplementation.
TRUE
Golden retriever ichthyosis is due to a mutation in what gene? Epdiermolytic or NON-epidermolytic? Mode of inheritance?
patatin-like phospholipase-1 (PNPLA1); non-epidermolytic; Autosomal recessive
What is the genetic mutation in Chianina & Shorthorn cattle that results in ichthyosis fetalis? What does the gene encode for?
ABCA12 – ATP-binding cassett transporter 12 protein –> major role in transportation of lipids in the epidermis, responsible for cholesterol efflux from keratinocytes
Phenotype of American Bulldog ichthyosis
poor haircoat, generalized white scales, ventral abdominal skin appears thickened with adherent brown scales; footpads may be mildly hyperkeratotic; Malassezia overgrowth –> pruritus
