Hair shaft structures in EDAR induced ectodermal dysplasia.
BACKGROUND
Mutations in the EDAR-gene cause hypohidrotic ectodermal dysplasia with defects in ectodermal appendage development including teeth, skin, exocrine glands and hair. Hair defects are sparsely described in genetically defined samples. The aim of this study was to investigate hair structures in three families with a heterozygous c.1072C > T mutation in the EDAR gene using scanning electron microscopy.


METHODS
Three Swedish families, where some members had a known c.1072C > T mutation in the EDAR gene with an autosomal dominant inheritance (AD) were included (n = 37) of which 17 carried the mutation and 20 did not. Thirty-two age and gender matched not related individuals served as a reference group. Confirmation of the c.1072C > T mutation in the EDAR gene was performed by genomic sequencing. Hairs were subjected to blinded scanning electron microscopy examination and hair defects were categorized and scored.


RESULTS
The minimum and maximum diameters of hairs were lower in the mutation group compared to the reference group. Subjects in the mutation group had to greater extent deep deformations in hair shafts compared to the non-mutation group and the reference group (p < 0.001).


CONCLUSIONS
Individuals with a c.1072C > T mutation in the EDAR-gene displayed more hair shaft deformations confirming the role of EDAR for human hair follicle development and postnatal hair follicle cycling.
Pediatric Dentistry, Department of Odontology, Faculty of Medicine, Umeå University, Umeå, Sweden. christina.stecksen-blicks@umu.se.
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Stecksén-Blicks
Pediatric Dentistry, Department of Odontology, Faculty of Medicine, Umeå University, Umeå, Sweden. catarina.falk.kieri@umu.se.
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Falk Kieri
Dermatology, Medicine, Department of Public Health and Clinical Medicine, Faculty of Medicine, Umeå University, Umeå, Sweden. david.hagg@umu.se.
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Hägg
Dermatology, Medicine, Department of Public Health and Clinical Medicine, Faculty of Medicine, Umeå University, Umeå, Sweden. marcus.schmitt-egenolf@umu.se.
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Schmitt-Egenolf
D004476:Ectodermal Dysplasia / Q000235:genetics / Q000473:pathology*; D053339:Edar Receptor / Q000235:genetics*; D006197:Hair / Q000648:ultrastructure*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D017354:Point Mutation / Q000235:genetics; D018709:Statistics, Nonparametric; D013548:Sweden
C506008:EDAR protein, human; D053339:Edar Receptor