MUTATIONS OF KERATINOCYTE TRANSGLUTAMINASE IN LAMELLAR ICHTHYOSIS

Lamellar ichthyosis Is a severe congenital skin disorder characterized by generalized large scales and variable redness. Affected individual s in three families exhibited drastically reduced keratinocyte transgl utaminase (TGK) activity. In two of these families, expression of TGK transcripts was diminished or abnormal and no TGK protein was detected . Homozygous or compound heterozygous mutations of the TGK gene were i dentified in all families. These data suggest that defects in TGK caus e lamellar ichthyosis and that intact cross-linkage of cornified cell envelopes is required for epidermal tissue homeostasis.