6

Question 1

There are four typically nonsyndromic ichthyoses

Answer 1

(a) ichthyosis vulgaris; (b) X-linked recessive ichthyosis (XLRI); (c) keratinopathic ichthyosis; and (d) autosomal recessive congenital ichthyosis (ARCI) (1).

Question 2

most common form of ichthyosis

Answer 2

Ichthyosis vulgaris (IV)

Question 3

Ichthyosis vulgaris (IV) develops within___ of life

Answer 3

the first few months

Question 4

caused by mutations in the____; inherited in a ___fashion

Answer 4

filaggrin gene; semiautosomal dominant

Question 5

The characteristic finding n IV is____

Answer 5

a reduced or absent granular layer

Question 6

helps to distinguish IV from other forms of ichthyosis

Answer 6

moderate degree of hyperkeratosis

Question 7

hyperkeratosis often extends into __ resulting in large keratotic follicular plugs. __is unremarkable.

Answer 7

the hair follicles, ; The dermis

Question 8

keratohyaline granules appear ___ which is evidence of defective synthesis

Answer 8

small and crumbly or spongy,

Question 9

X-linked recessive ichthyosis (XLRI) is caused by a mutation in the ___encoding___, which in nearly 90% of cases results from ___

Answer 9

ARSC1 gene ; steroid sulfatase; gene deletion.

Question 10

__ Is concentrated in lamellar bodies and degrades cholesterol sulfate, which provides the cholesterol “mortar” between “brick” corneocytes in the cornified envelope.

Answer 10

Steroid sulfatase

Question 11

.__also functions as a serine protease inhibitor in the epidermis and is required for __

Answer 11

Cholesterol sulfate ; orderly corneocyte degradation and normal desquamation.

Question 12

. ___ leads to persistent cell cohesion with delayed dissolution of desmosomes in the stratum spinosum, leading to __

Answer 12

Increased cholesterol sulfate ; retention hyperkeratosis

Question 13

for ichthyoses resulting from mutations in keratin genes, which include epidermolytic ichthyosis, ichthyosis en confetti, and superficial epidermolytic ichthyosis

Answer 13

Keratinopathic ichthyosis

Question 14

Epidermolytic ichthyosis (EI) is caused by mutations in__ & ___ genes and is typically inherited in an ___ fashion

Answer 14

the keratin 1 (KRT1) or keratin 10 (KRT10); autosomal dominant

Question 15

generalized tender erythema from the time of birth, with the development of superficial bullae and erosions

Answer 15

Epidermolytic ichthyosis (EI)

Question 16

Vesicles, bullae, and erosions typically resolve within ___, to be replaced by thick brown, verrucous scaling that predominates over time

Answer 16

the first few years

Question 17

__ show marked involvement with ___ particularly in flexural areas, leading to the appearance of__

Answer 17

flexural surfaces ; furrowed hyperkeratosis; “corrugated cardboard.”

Question 18

___ is a characteristic histologic finding in the epidermis of EI

Answer 18

Epidermolytic hyperkeratosis (EHK)

Question 19

A markedly thickened granular layer containing an increased number of__ & ___

Answer 19

irregularly-shaped keratohyaline granules and compact hyperkeratosis

Question 20

The upper dermis in EHK shows a

Answer 20

moderately severe, chronic inflammatory infiltrate

Question 21

The essential electron microscopic features of EHK are

Answer 21

excessive production of tonofilaments and premature formation of keratohyaline granules.

Question 22

In EHK many desmosomes are attached to only __ keratinocyte instead of connecting __ neighboring keratinocytes,

Answer 22

1; 2

Question 23

Although EHK is found in all cases of EI, it can also be seen as an isolated histologic finding in other benign dermatoses and neoplasms, including

Answer 23

epidermolytic palmoplantar keratoderma, solitary epidermolytic acanthoma, disseminated epidermolytic acanthoma, and an epidermal nevus,

Question 24

is an autosomal dominant disorder also caused by mutations in KRT1 or KRT10.

Answer 24

Ichthyosis with confetti

Question 25

Affected patients are born with exfoliative erythroderma and palmoplantar keratoderma, becomes peppered with numerous pale “confetti-like” islands of normal skin during childhood

Answer 25

Ichthyosis with confetti

Question 26

shows epidermal acanthosis with disordered differentiation above the basal layer, perinuclear vacuolization, hypogranulosis, and hyperkeratosis with retained nuclei in the stratum corneum

Answer 26

Ichthyosis with confetti

Question 27

Ichthyosis with confetti has been shown to result from ___ where islands of normal intervening skin appear due to loss of heterozygosity in the KRT10 gene via mitotic recombination

Answer 27

revertant mosaicism,

Question 28

ichthyosis bullosa of Siemens, is caused by mutations in the __ gene,

Answer 28

KRT2e

Question 29

T/f: ichthyosis bullosa of Siemens is marked by more superficial blistering than EI

Answer 29

T

Question 30

T/F : Skin biopsies of ichthyosis bullosa of Siemens are similar to EI with EHK in the upper spinous and granular layers.

Answer 30

T

Question 31

Autosomal Recessive Congenital Ichthyosis (ARCI) is a collection of various disorders that includes a range of phenotypes including __

Answer 31

harlequin ichthyosis (HI), lamellar ichthyosis (LI), and nonbullous congenital ichthyosiform erythroderma (CIE)

Question 32

is the most severe ARCI phenotype, and patients are born with fissured ichthyosiform polygonal plaques

Answer 32

harlequin ichthyosis (HI)

Question 33

__ phenotype demonstrate fine white scales with fairly pronounced erythroderma that may improve with age.

Answer 33

CIE

Question 34

__ phenotype is characterized by large, plate-like “fish” scales, although there is a spectrum of severity ranging from mild disease to more severe involvement with ectropion, eclabium, and scarring alopecia

Answer 34

LI

Question 35

T/F: In all forms, the flexural surfaces and the palms and soles are not involved.

Answer 35

F: are involved

Question 36

Most patients with the lamellar phenotype have mutations in the gene encoding___, which cross-links proteins in the cornified envelope

Answer 36

transglutaminase 1 (TGM1)

Question 37

HI results from nonsense mutations in the ___, leading to ____,__ and ___. Massive___ results

Answer 37

ABCA12 transporter gene, ; deficiency of proteases in the stratum corneum dysregulated lipid transport with abnormal lamellar bodies, and premature differentiation of keratinocytes.; orthokeratosis

Question 38

Missense mutations in ABCA12 produce __ due to the presence of some functioning protein

Answer 38

milder LI or CIE phenotypes

Question 39

Mutations in ___, ___, also lead to ARCI through disruption of lipid synthesis and/or processing of filaggrin

Answer 39

ALOX12B (12(R)-lipoxygenase, ALOXE3 (lipoxygenase-3), CYP4F22 (cytochrome p450 subunit), and NIPAL4 (ichthyin)

Question 40

Typically, histopathology of __ shows mild thickening of the stratum corneum with foci of parakeratosis, while LI demonstrates a ___.

Answer 40

CIE; markedly thickened stratum corneum without areas of parakeratosis

Question 41

On electron microscopy, HI demonstrates ___

Answer 41

absent lamellar granules in the stratum granulosum

Question 42

Sjögren–Larsson syndrome: disorder is due to mutations in the ___ which converts fatty alcohol to fatty acid

Answer 42

Fatty aldehyde dehydrogenase gene (FALDH),

Question 43

erythroderma early in life, with fine white scaling in flexural areas with mental retardation and spastic paresis

Answer 43

Sjögren–Larsson syndrome

Question 44

is an X-linked dominant form of chondrodysplasia punctata, which is characterized by punctate epiphyseal calcifications, asymmetric skeletal abnormalities, ichthyosiform areas in a blaschkoid distribution (termed ptychotropism), and cataracts.

Answer 44

Conradi–Hunermann syndrome

Question 45

Conradi–Hunermann syndrome: X-chromosomal inactivation in girls produces the __, and the underlying defect occurs in the pathway of __

Answer 45

blaschkoid skin findings and asymmetric bone involvement; of cholesterol synthesis and metabolism.

Question 46

Conradi–Hunermann syndrome : Mutations have been found in the ___, which encodes ___

Answer 46

emopamil-binding protein (EBP) gene ; 3β-hydroxysteroid delta 8, delta 7 sterol isomerase

Question 47

is an autosomal recessive condition marked by the triad of ichthyosis, atopic diathesis, and hair shaft deformities, most commonly trichorrhexis invaginata.

Answer 47

Netherton syndrome (NS)

Question 48

The classic skin finding in NS is ___, which is not typically seen until early childhood and manifests as __

Answer 48

ichthyosis linearis circumflexa; extensive migratory polycyclic lesions of erythema and scaling.

Question 49

Bamboo hair is thought to represent a defect involving the __

Answer 49

inner root sheath

Question 50

Patients typically have elevated eosinophils and IgE with severe atopy including eczema, asthma, food allergies, and anaphylaxis

Answer 50

NS

Question 51

resemblance to psoriasis, such as elongation of the rete ridges and hyperkeratosis, as well as parakeratosis.

Answer 51

NS

Question 52

NS is caused by mutations in the gene __which encodes ___, a serine protease inhibitor. Deficiency of LEKTI causes epidermal protease hyperactivity, leading to ___ in turn leading to atopy

Answer 52

SPINK5, ; LEKTI (Lymphoepithelial Kazal-Type Inhibitor); desmosomal degradation, detachment of the stratum corneum, and activation of TH2 cytokines

Question 53

Trichothiodystriphy is otherwise known as IBIDS syndrome due to characteristic features of ____. Patients with these syndromes have sulfur-deficient, sparse hair, which demonstrates a characteristic ___appearance under polarized microscopy

Answer 53

Ichthyosis, Brittle hair, Impaired intelligence, Decreased fertility, and Short stature. ; “tiger tail”

Question 54

is an autosomal recessive disorder characterized by generalized ichthyosis, cerebellar ataxia, progressive paresis of the extremities, and retinitis pigmentosa,

Answer 54

Refsum disease

Question 55

Refsum disease- Pathognomonic findings occur in the __ cells of the epidermis, which demonstrate __

Answer 55

basal and suprabasal ; variably sized vacuoles that contain lipid accumulations

Question 56

Refsum disease is caused by mutations in two genes:___. both of which lead to the accumulation of phytanic acid Treatment is __

Answer 56

the PAHX gene and the PEX7 gene ; avoidance of phytanic acid-containing foods.

Question 57

Its hallmark is a unilateral ichthyosiform erythroderma that does not cross the midline with ipsilateral hypoplasia of the affected limb

Answer 57

CHILD syndrome is an X-linked dominant disease characterized by Congenital Hemidysplasia with Ichthyosiform erythroderma and Limb Defects.

Question 58

CHILD syndrome is due to mutations in the __, which encodes the enzyme 3β-hydroxysteroid dehydrogenase that converts lanosterol to cholesterol

Answer 58

NSHDL gene

Question 59

characterized by infiltration of papillary dermal tips with foamy macrophages

Answer 59

verruciform xanthoma (VX)

Question 60

A rare, autosomal dominant, inherited disorder, erythrokeratoderma variabilis (EKV), typically starts in infancy and is characterized by two striking morphologies ____ and ____

Answer 60

First, areas of erythema expand centrifugally and coalesce into circinate figures. These lesions fluctuate over days to weeks in their configuration and extent and thus are “variable.” Second, persistent yellow to brown hyperkeratotic plaques develop both within the areas of erythema and in areas of apparently normal skin.

Question 61

Progressive symmetric erythrokeratoderma (PSEK is best distinguished from EKV by

Answer 61

the facial involvement and absence of migratory erythema,

Question 62

T/F: The changes are nonspecific in both EKV and PSEK

Answer 62

T

Question 63

EKV is caused by mutations in

Answer 63

I GJB3 encoding connexin 31 and GJB4 encoding connexin 30.3

Question 64

The molecular pathogenesis of the inherited forms of PPK are linked to abnormalities in ___

Answer 64

intracellular structural proteins (keratins), cornified envelope proteins (loricrin, transglutaminase), cell–cell connections (desmoglein, desmoplakin, plakophilin, connexins), and enzymatic signaling transduction (cathepsins)

Question 65

Answer 65

Memrize