Disorders of Keratinization

Question 1

Ichthyosis

Answer 1

general term applied to a group of skin disorders resulting from excessive keratinization–formation of horny layers of the skin.

Skin is characterized by dryness and scaling, which may involve the entire body surface.

Question 2

Harlequin Fetus

Answer 2

results from a rear keratinizing disorder that is inherited as an autosomal recessive trait with a mutation on the ABCA12 gene.

The skin is markedly thickened, ridged, and cracked. Most affected neonates die during first week of life.

Question 3

Collodion infant

Answer 3

Infant is covered by a thick, taut membrane that resembles collodion (protective film) or parchment. The membranous skin cracks with the first respiratory efforts and begins to fall off in large sheets.

Most Common Cause: Deficiency of transglutaminase-1

Complete shedding may take several weeks, occasionally leaving normal appearing skin

Question 4

Lamellar icthyosis

Answer 4

Autosomal recessive disorder. First appears like a collodion infant; however, the scaling persists.

Growth of hair may be curtailed and sweat glands are often impeded.

Infants usually suffer severely in the hot weather because of their inability to sweat.