Mutations in keratinocyte transglutaminase are implicated in lamellar ichthyosis. Urea 40% is indicated for psoriasis, xerosis, onychomycosis, ichthyosis, eczema, keratosis, keratoderma, corns, and calluses. As such it is used to treat warts, calluses, psoriasis, dandruff, acne, ringworm, and ichthyosis. As such, it is used to treat warts, psoriasis, acne, ringworm, dandruff, and ichthyosis. The most common type known as ichthyosis vulgaris. This term is used to describe a certain type of ichthyosis, a congenital skin condition. It is used to treat harlequin-type ichthyosis, a usually lethal skin disease, and lamellar ichthyosis. There can be ocular manifestations of ichthyosis, such as corneal and ocular surface diseases. Deficiency of the enzyme leads to the characteristic dry and scaly skin seen in ichthyosis. The exact mutation is only known for some cases of ichthyosis vulgaris. Lamellar Ichthyosis often presents with a "colloidal" membrane at birth. Newborns with harlequin-type ichthyosis present with thick, fissured armor-plate hyperkeratosis. Ichthyosis vulgaris accounts for more than 95% of cases. The condition can resemble but is different from harlequin type ichthyosis. Genetic testing is the most specific diagnostic test for harlequin ichthyosis.