title: Bathing suit ichthyosis is caused by transglutaminase-1 deficiency: evidence for a temperature-sensitive phenotype.
abstract: Bathing suit ichthyosis (BSI) is a striking and unique clinical form of autosomal recessive congenital ichthyosis characterized by pronounced scaling on the bathing suit areas but sparing of the extremities and the central face. Here we report on a series of 10 BSI patients. Our genetic, ultrastructural and biochemical investigations show that BSI is caused by transglutaminase-1 (TGase-1) deficiency. Altogether, we identified 13 mutations in TGM1-among them seven novel missense mutations and one novel nonsense mutation. Structural modeling for the Tyr276Asn mutation reveals that the residue is buried in the hydrophobic interior of the enzyme and that the hydroxyl side chain of Tyr276 is exposed to solvent in a cavity of the enzyme. Cryosections of healthy skin areas demonstrated an almost normal TGase activity, in contrast to the affected BSI skin, which only showed a cytoplasmic and clearly reduced TGase-1 activity. The distribution of TGase-1 substrates in the epidermis of affected skin corresponded to the situation in TGase-1 deficiency. Interestingly, the expression of TGase-3 and cathepsin D was reduced. Digital thermography validated a striking correlation between warmer body areas and presence of scaling in patients suggesting a decisive influence of the skin temperature. In situ TGase testing in skin of BSI patients demonstrated a marked decrease of enzyme activity when the temperature was increased from 25 to 37 degrees C. We conclude that BSI is caused by TGase-1 deficiency and suggest that it is a temperature-sensitive phenotype.
authors.affiliation: Department of Dermatology, University of Muenster, Von-Esmarch-Str. 58 D-48149, Münster, Germany. ojiv@mednet.uni-muenster.de
authors.forename: Vinzenz
authors.initials: V
authors.lastname: Oji
authors.forename: Juliette Mazereeuw
authors.initials: JM
authors.lastname: Hautier
authors.forename: Bijan
authors.initials: B
authors.lastname: Ahvazi
authors.forename: Ingrid
authors.initials: I
authors.lastname: Hausser
authors.forename: Karin
authors.initials: K
authors.lastname: Aufenvenne
authors.forename: Tatjana
authors.initials: T
authors.lastname: Walker
authors.forename: Natalia
authors.initials: N
authors.lastname: Seller
authors.forename: Peter M
authors.initials: PM
authors.lastname: Steijlen
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Küster
authors.forename: Alain
authors.initials: A
authors.lastname: Hovnanian
authors.forename: Hans Christian
authors.initials: HC
authors.lastname: Hennies
authors.forename: Heiko
authors.initials: H
authors.lastname: Traupe
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002874:Chromosome Mapping; D018389:Codon, Nonsense; D005260:Female; D006801:Humans; D007057:Ichthyosis / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D007223:Infant; D008297:Male; D008958:Models, Molecular; D020125:Mutation, Missense; D010641:Phenotype; D017422:Sequence Analysis, DNA; D012867:Skin / Q000201:enzymology / Q000473:pathology; D013696:Temperature; D011503:Transglutaminases / Q000737:chemistry / Q000172:deficiency* / Q000235:genetics* / Q000378:metabolism
chemical_list: D018389:Codon, Nonsense; D011503:Transglutaminases; C105804:transglutaminase 1