SAD - Chapter 12 - Congenital Keratinization Defects Flashcards

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1
Q

An autosomal dominant mutation in what gene(s) of Rhodesian or Thai ridgebacks result(s) in formation of a dermoid sinus?

A

fibroblast growth factors (FGF3, FGF4, FGF19)

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2
Q

T/F: Animals with follicular parakeratosis have normal nasal planums and footpads.

A

TRUE

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3
Q

What are the clinical features of urticaria pigmentosa?

A

macular and/or crusted papular rash on head and neck, +/- pruritus, +/- hyperpigmentation

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4
Q

What is the pigmentary abnormality with color dilution alopecia?

A

irregularities in melanin transfer and storage – mature (stage IV) melanosomes are stored irregularly in hairs and epidermal keratinocytes and vacuolization of melanocytes in some hair bulbs

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5
Q

Darier disease is due to mutations in genes that encode what molecules?

A

calcium pumps

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6
Q

What are the clinical features of dermatomyositis?

A

skin lesions in areas of mechanical trauma (face, periocular, muzzle, tips of ears, carpal/tarsal region, digits, tip of the tail, onychorrhexis): alopecia, erythema, scale, crust, ulceration

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7
Q

Cats with a blue or cream-colored coat carry what dilution gene?

A

Maltese dilution gene

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8
Q

An autosomal recessive ectodermal dysplasia-skin fragility syndrome of Chesapeak Bay retrievers has been shown to be due to what defects?

A

reduced number of partially formed desmosomes; due to lack of plakophilin-1 and anomalies in desmoplakin and keratins 10 & 14

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9
Q

___ is longitudinal splitting of the distal end of a hair.

A

trichoptilosis

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10
Q

___ is a rare disorder of young intact male Kerry blue terriers where affected dogs have multiple, hard, brittle follicular spicules.

A

Spiculosis

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11
Q

In addition to hair loss, animals with ectodermal dysplasia have abnormalities in what other organ systems?

A

dentition and glandular formation/function (epitrichial and atrichial sweat, sebaceous, lacrimal, tracheal and bronchial)

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12
Q

An autosomal recessive primary seborrhea has been reported in what breed ofr cats?

A

Persians

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13
Q

Dystrophic epidermolysis bullosa results from decreased expression of what protein? Due to a defect in what gene?

A

collagen VII; mutation in COL7A1 gene

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14
Q

What can worsen the skin lesions of dermatomyositis?

A

trauma and solar exposure

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15
Q

What is the skin extensibility index for dogs affected with Ehlers Danlos? Cats?

A

> 14.5% - dogs, >19% - cats

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16
Q

What are clinical signs of myositis in animals with dermatomyositis?

A

dysphagia, megaesophagus, high-stepping stiff gait, asymptomatic muscle atrophy

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17
Q

In the German Shorthaired Pointer, ______ is an autosomal recessive trait associated with decreased expression of laminin-332.

A

junctional epidermolysis bullosa

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18
Q

Familial footpad hyperkeratosis has been described in what breed(s)?

A

Irish terriers and Dogue de Bordeaux

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19
Q

____ is a neural tube defect resulting from incomplete separation of the skin and neural tube during embryonic development.

A

Dermoid sinus

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20
Q

T/F: The presence of melanin clumping is diagnostic for color dilution alopecia.

A

False - indicates action of dilution genes, does not necessarily mean the animal has color dilution alopecia

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21
Q

In the German Shorthaired Pointer, junctional epidermolysis bullosa is an autosomal recessive trait associated with decreased expression of what?

A

laminin-332 laminin 5)

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22
Q

What are the clinical lesions of canine Darier disease?

A

alopecia, erythema, scaling –> plaquelike

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23
Q

What is the primary cause of acral mutilation syndrome?

A

pathologic lesions at the level of the primary sensory neuron, decrease in promeninence of the spinal ganglia and dorsal roots

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24
Q

With epidermolysis bullosa simplex, where does clefting occur?

A

basal layer of epidermis (most superficial of epidermolysis bullosa types)

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25
Q

Darier disease due to abnormal calcium homeostasis has been reported in what breed(s)?

A

English setters, Doberman pinscher

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26
Q

Histopathologic changes with lethal acrodermatitis of Bull terriers?

A

diffuse parakeratotic hyperkeratosis with focal crusting and intraepidermal pustules; superficial epidermis may have laminar pallor

27
Q

Cutis laxa is due to abnormalities in what structure?

A

elastic fibers

28
Q

What is the defect in Ehlers Danlos?

A

structural changes in collagen – forms twisted ribbons rather than cylindrical fibrils and fibers; procollagen processing defect –> decreased activity of procollagen peptidase and an accumulation of partially processed type I procollagen, decreased collagenase activity

29
Q

An ulcerative nasal dermatitis has been reported in what breed of cats?

A

Bengal cats

30
Q

What are the clinical features of canine cyclic hematopoiesis?

A

silver-gray hair coat, light-colored nose

31
Q

Canine cyclic hematopoiesis results from a mutation of the gene encoding what protein?

A

dog adaptor protein complex 3 (APB3)

32
Q

Canine darier disease has been repoted in English setters due to a depltion of what?

A

SERCA2-gated stores

33
Q

What are the histopathologic changes are present with pattern baldness?

A

decrease in size (miniaturization) of the hair follicles and hair shafts with normal adnexal structures; follicles are shorter and thinner, hae smaller hair bulbs, and produce fine hair shafts

34
Q

With junctional epidermolysis bullosa, where does clefting occur?

A

lamina lucida of the dermoepidermal basement membrane

35
Q

What is the defect in canine Darier disease and why does it result in clinical disease?

A

mutation in gene encoding calcium pumps, impairs desmosomal function or epidermal differentiation –> epidermis cannot withstand trauma and vesiculobullous lesions develop in response to friction or infecton

36
Q

What are the histopathologic features of Schnauzer comedo syndrome?

A

keratinous plug blocking the hair follicle and sebaceous gland –> cystic cavity is formed by stretched follicular epithelium and filled with keratin and sebum

37
Q

T/F: Mexiacn hairless dogs have a shorter lifespan than their haired relatives.

A

True - unclear if there is a familial immunoincompetence linked to hairlessness

38
Q

Which typically occurs first with dermatomyositis: skin or muscle lesions?

A

skin - myositis typically occurs months after the skin lesions

39
Q

Canine cyclic hematopoiesis has what mode of inheritance?

A

lethal autosomal recessive

40
Q

T/F: Biopsy is necessary to confirm a diagnosis of idiopathic facial dermatitis of Persian and Himalayan cats.

A

False - is often nondiagnostic

41
Q

Chediak-Higashi syndrome has what mode of inheritance?

A

autosomal recessive

42
Q

What are the histopathologic features of follicular lipidosis?

A

severe swelling of the matrix cells of anagen hair follicles due to accumulation of lipid within the cell’s cytoplasm

43
Q

What are the histopathologic features of dermatomyositis?

A

hydropic degeneration of surface and follicular basal cells; apoptotic basal cells (Civatte bodies); perivascular to interstitial dermatitis; follicular atrophy and perifollicular fibrosis; vasculitis

44
Q

What is the presenting complaint with follicular lipidosis?

A

hair loss in the mahogany points of the face (in Rottweilers)

45
Q

What are the clinical features of psoriasiform-lichenoid dermatosis?

A

erythematous, lichenoid papules and plauqes on pinnae, external ear canal, inguinal region –> become hyperkeratotic

46
Q

Psoriasiform-lichenoid dermatosis is reported in what breed?

A

English Springer Spaniels

47
Q

Why are animals with ectodermal dysplasia more prone to respiratory infections?

A

decreased glandular secretions and impaired thermoregulation

48
Q

Vitamin D analogs alter epidermal proliferation and terminal differentiation and may be useful for treatment of primary seborrhea. What needs to be monitored with calcitriol therapy? Why?

A

electrolyte levels, esp. calcium, because calcitriol can decrease parathyroid hormone

49
Q

What stain is used to identify collagen disorders?

A

Masson trichrome stain

50
Q

What are the clinical lesions of junctional epidermolysis bullosa?

A

erosive to ulcerative lesions over bony prominences of the face, pinna, pressure points on the limbs or footpads, oral cavity

51
Q

What is the most common cutaneous manifestation of mastocytosis?

A

urticaria pigmentosa

52
Q

T/F: Steroids are beneficial in the treatment of canine darier disease.

A

Unclear – in humans has clear benefit but not reported in dogs

53
Q

Histopathologic features of canine darier disease?

A

acanthosis w/ orthokeratotic and parakeratotic hyperkeratosis and marked, diffuse acantholysis of lower and middle portions of epidermis and follicular outer root sheath

54
Q

Histopathologic features of color dilution alopecia?

A

sebaceous melanosis, melanin clumping in epidermal and follicular basal cells and hair matrix cells, macromelanosomes in hair shafts, peribulbar melanophages, follicular hyperkeratosis, fractured hair shafts, free clumps of melanin

55
Q

Acral mutilation syndrome has been reported in what breeds?

A

German shorthaired pointers, English springer spaniel, English pointer dogs, French spaniels, miniature pinscher

56
Q

What histopathologic changes are present with black hair follicular dysplasia?

A

clumped melanin in epidermal and follicular basal cells and hair matrix cells; macromelanosomes visible within hair shafts; follicles are irregular, dilated, and filled with keratin, fragments of hair shafts, large clumps of free melanin

57
Q

What are the histopathologic features of psoriasiform-lichenoid dermatosis?

A

superficial perivascular to interstitial dermatitis with psoriasiform epidermal hyperplasia and areas of lichenoid interface dermatitis, intraepidermal microabscesses (containing eos and neuts), Munro microabscesses

58
Q

Follicular lipidosis has been reported in what breed?

A

Rottweiler

59
Q

What changes are present on skin biopsy with Ehlers Danlos?

A

changes may not be present in cats; collagen fibers may be more eosinophilic than normal and blurred in appearance, fragmented, shortened and disoriented; form irregularly sized bundles

60
Q

Darier disease has an autosomal (dominant/recessive) mode of inheritance?

A

dominant

61
Q

What changes are present on skin biopsy with ectodermal dysplasia?

A

hair follicles, arrector pili muscles, sebaceous glands, and epitrichial sweat glands are reduced in number, hypoplastic or absent

62
Q

_____ is an acquired defect in which external insults damage the cuticle and weaken the hair shaft.

A

trichorrhexis nodosa

63
Q

Where does the split occur with dystrophic epidermolysis bullosa?

A

sub-basilar dermoepidermal separation (beneath the lamina densa)

64
Q

Dermoid sinus has been reported in what breed of cats?

A

Burmese