WCVD 2020 - Diseases of Keratinization

Question 1

X-linked hypohidrotic ectodermal dysplasia results from a mutation in what gene?

Answer 1

ectodysplasin-A (EDA) gene

Question 2

Histopathologic features of hereditary nasal parakeratosis

Answer 2

marked parakeratosis with serum lakes between cell layers of the nose

Question 3

DDX for canine acne

Answer 3

demodicosis, dermatophytosis, contact hypersensitivity

Question 4

T/F: Acitrentin can upregulate the activity of ABCA6 to partially compensate for a lack of ABCA12.

Answer 4

TRUE

Question 5

Jack Russell Terriers have a mutation in the gene that encodes for what? Epidermolytic or NON-epidermolytic ichthyosis? Mode of inheritance

Answer 5

transglutaminase-1; NON-epidermolytic; Autosomal Recessive

Question 6

Ichthyosis in Cavalier King Charles Spaniels results from a mutation in what gene? What is clinical presentation?

Answer 6

FAM83H; dry eye and frizzy haircoat, dorsal scaling, footpad hyperkeratosis, and deformed claws that may slough (Congenital Keratoconjunctivitis Sicca and Ichthyosform Dermatosis)

Question 7

Equine Linear Keratosis has been reported in what breed?

Answer 7

Quarter Horses

Question 8

Mutations in the genes that encode for what structures result in epidermolytic ichthyosis?

Answer 8

keratins

Question 9

T/F: The footpads, claws, hair and teeth of Norfolk terriers with mutations in keratin 10 are normal.

Answer 9

TRUE

Question 10

Histopathologic features of epidermolytic ichthyosis?

Answer 10

vacuoles and lysis of keratinocytes in stratum spinosum and stratum granulosum, hypergranulosis, hyperkeratosis

Question 11

Great Dane ichthyosis results from a mutation in what gene?

Answer 11

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

Question 12

What does the gene patatin-like phospholipase-1 encode for? Mutations result in what disease?

Answer 12

acylceramide, role in glycerophospholipid metabolism and cutaneous barrier function; Golden retriever ichthyosis (rough haircoat and scaling)

Question 13

Which keratins are present in the upper layers of the epidermis?

Answer 13

keratins 1, 2, 10

Question 14

Mutations in the genes that encode for what structures result in NON-epidermolytic ichthyosis?

Answer 14

lipids, non-keratin proteins, or desquamation

Question 15

American bulldog ichthyosis is due to a mutation in what gene? Epidermolytic or NON-epidermolytic? Mode of inheritance?

Answer 15

NIPAL4 (nuclear interaction partner of ALK-like domain containing 4); non-epidermolytic; autosomal recessive

Question 16

Hairlessness of the American hairless terrier is due to what genetic mutation?

Answer 16

frameshift deletion of serum glucocorticoid regulated kinase family member 3 gene (SGK3)

Question 17

Genetic mutation responsible for hereditary nasal parakeratosis?

Answer 17

SUV39H2 gene

Question 18

T/F: Cattle with bovine hereditary zinc deficiency improve with zinc supplementation.

Answer 18

TRUE

Question 19

T/F: Supplementation of aciretin to pregnant sows with a mutation in the ABCA12 gene resulted in improved phenotype and longer survival.

Answer 19

TRUE

Question 20

T/F: American hairless terriers are born hairless.

Answer 20

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

Question 21

DDX for Schnauzer Comedo syndrome

Answer 21

demodicosis, dermatophytosis, bacterial folliculitis, hyperadrenocorticism, hypothyroidism, follicular dystrophy

Question 22

Flechvieh cattle have an autosomal recessive cornification disorder due to a mutation of what gene?

Answer 22

PLD4 – phospholipase encoding gene

Question 23

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?

Answer 23

Akhal-Teke horses; ST14 –> serine protease involved in epidermal development

Question 24

Mutation in aspartic peptidase, retroviral-like 1 results in what changes? What clinical disease?

Answer 24

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

Question 25

T/F: The footpads, claws, hair and teeth of Jack Russell Terriers with mutations in transglutaminase-1 are normal.

Answer 25

False – footpad hyperkeratosis, onchyomalacia is present

Question 26

Hereditary nasal parakeratosis has been reported in what breeds of dog?

Answer 26

Labs and greyhounds

Question 27

T/F: Chinese crested dogs are homozygous for the mutation of forkhead box transcription factor 13 (FOX13), resulting in the hairless phenotype.

Answer 27

False - is an autosomal DOMINANT inheritance pattern, homozygous mutation is LETHAL

Question 28

Bovine hereditary zinc deficiency has been reported in what breeds? Mode of inheritance?

Answer 28

Black pied Fresian cattle, Holstein-Fresians, shorthorns, Angus; Autosomal recessive

Question 29

Familial paw pad hyperkeratosis due to a mutation in the FAM83G has been reported in what breeds?

Answer 29

Dromfohrlander, Irish terriers, Dogues de Bordeaux

Question 30

T/F: Bull terriers with lethal acrodermatitis improve with zinc supplementation.

Answer 30

FALSE

Question 31

X-linked hypohidrotic ectodermal dysplasia has been reported most commonly in what breeds?

Answer 31

dachshunds, GSD, poodles, mixed breeds

Question 32

Norfolk terriers have a mutation in the gene that encodes for what? Is this an epidermolytic or NON-epidermolytic ichthyosis? Mode of inheritance?

Answer 32

Keratin 10; Epidermolytic; Autosomal Recessive

Question 33

What breed of cattle have been reported to have ichthyosis fetalis?

Answer 33

Chianina & Shorthorn cattle

Question 34

What breeds are reported to have epidermolytic ichthyosis?

Answer 34

Norfolk terriers, Rhodesian ridgebacks, Labs, CKCS

Question 35

German shepherd dog ichthyosis is due to a mutation in what gene? Epidermolytic or NON-epidermolytic? Mode of inheritance?

Answer 35

aspartic peptidase retroviral-like 1 (ASPRV1); non-epidermolytic; autosomal recessive

Question 36

T/F: Flechvieh cattle with the autosomal recessive cornification disorder due to a mutation in PLD4 improve with zinc supplementation.

Answer 36

FALSE

Question 37

Lethal acrodermatitis of bull terriers is due to a mutation in what gene? What is its function?

Answer 37

MKLN1 gene –> encodes intracellular protein muskelin-1 –> functions in cell adhesion and intracellular transport processes

Question 38

Hairlessness in Chinese crested, Mexican xoloitcuintle and Peruvian Inca orchid dogs is due to a mutation in what gene? What does this gene regulate?

Answer 38

forkhead box transcription factor 13 (FOX13); regulates ectodermal development, postnatal hair growth and hair regeneration

Question 39

What are characteristic features of ichthyosis fetalis?

Answer 39

microtia and eversion of skin of the lips and eyelids

Question 40

What are the terminal breakdown products of filaggrin that are the main components of “natural moisturizing factor”?

Answer 40

pyrrolidone carboxylic acid and urocanic acid

Question 41

T/F: Pharoah hounds with lethal acrodermatitis improve with zinc supplementation.

Answer 41

TRUE

Question 42

Golden retriever ichthyosis is due to a mutation in what gene? Epdiermolytic or NON-epidermolytic? Mode of inheritance?

Answer 42

patatin-like phospholipase-1 (PNPLA1); non-epidermolytic; Autosomal recessive

Question 43

What is the genetic mutation in Chianina & Shorthorn cattle that results in ichthyosis fetalis? What does the gene encode for?

Answer 43

ABCA12 – ATP-binding cassett transporter 12 protein –> major role in transportation of lipids in the epidermis, responsible for cholesterol efflux from keratinocytes

Question 44

Phenotype of American Bulldog ichthyosis

Answer 44

poor haircoat, generalized white scales, ventral abdominal skin appears thickened with adherent brown scales; footpads may be mildly hyperkeratotic; Malassezia overgrowth –> pruritus