title: Transglutaminase 1 expression in a patient with features of harlequin ichthyosis: case report.
abstract: Harlequin ichthyosis (HI) is a life-threatening disorder characterized clinically by massive generalized hyperkeratosis and ultrastructurally by an absence of lamellar bodies. However, infants who survive the perinatal period develop a phenotype resembling the nonbullous ichthyosiform erythrodermic (CIE) form of autosomal recessive ichthyosis. We studied a child with a severe hyperkeratotic skin disorder present at birth that developed into a CIE-like phenotype. Electron microscopy demonstrated an absence of lamellar bodies consistent with HI. Abnormalities of filaggrin and involucrin expression by immunostaining were evident. However, transglutaminase 1 (TGase1) was expressed in the epidermis in a pattern consistent with other diseases that involve epidermal acanthosis. Analysis of patient keratinocytes grown in vitro demonstrated expression of normal amounts of TGase1 mRNA and full length TGase1 protein, as well as normal levels of transglutaminase enzymatic activity.
authors.affiliation: V.A. Palo Alto Health Care System, Department of Dermatology, Stanford University, California 94304, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Choate
authors.forename: M L
authors.initials: ML
authors.lastname: Williams
authors.forename: P M
authors.initials: PM
authors.lastname: Elias
authors.forename: P A
authors.initials: PA
authors.lastname: Khavari
mesh_terms: D015415:Biomarkers; D002675:Child, Preschool; D004817:Epidermis / Q000201:enzymology / Q000648:ultrastructure; D000091344:Filaggrin Proteins; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006801:Humans; D007057:Ichthyosis / Q000201:enzymology* / Q000473:pathology; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000378:metabolism; D008854:Microscopy, Electron; D011498:Protein Precursors / Q000378:metabolism; D011503:Transglutaminases / Q000235:genetics* / Q000378:metabolism
chemical_list: D015415:Biomarkers; C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins; D011498:Protein Precursors; C032253:involucrin; D011503:Transglutaminases; C105804:transglutaminase 1