Hereditary mucoepithelial dysplasia: clinical, ultrastructural and genetic study of eight patients and literature review.

F. Boralevi, M. Haftek, P. Vabres, S. Lepreux, C. Goizet, C. Leaute-Labreze, A. Taieb
Br J Dermatol. 2005-08-01; 153(2): 310-318
DOI: 10.1111/j.1365-2133.2005.06664.x

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1. Br J Dermatol. 2005 Aug;153(2):310-8.

Hereditary mucoepithelial dysplasia: clinical, ultrastructural and genetic study
of eight patients and literature review.

Boralevi F(1), Haftek M, Vabres P, Lepreux S, Goizet C, Leaute-Labreze C, Taieb

Author information:
(1)Paediatric Dermatology Unit, Hôpital Pellegrin, Bordeaux, France.

BACKGROUND: Hereditary mucoepithelial dysplasia is a dominantly inherited
disease, mainly characterized by chronic mucosal lesions associated with
keratitis, non-scarring alopecia, keratosis pilaris and perineal intertrigo.
Since the original report by Witkop, this condition has been considered to be a
disorder of desmosome/gap junction formation, but there has been no ex vivo
investigation of these components using genetic and immunolabelling techniques.
OBJECTIVES: To perform light and immunoelectron microscopic studies, and partial
genetic analysis on five patients in a family and three sporadic cases and to
point out similarities of this rare disorder with chronic mucocutaneous
candidiasis and other follicular keratosis syndromes, i.e. ichthyosis
follicularis-alopecia-photophobia (IFAP), keratitis-ichthyosis-deafness (KID) and
Siemens syndromes.
METHODS: Biopsies from the involved oral mucosa and armpit skin of patient 1 were
prepared for standard histopathology, electron microscopy and
immunocytochemistry. Microsatellite genotyping was performed in three affected
family members. Direct sequencing after polymerase chain reaction amplification
of the entire coding region was performed.
RESULTS: A 14-year-old male had recurrent keratitis, widespread keratosis
pilaris, perineal intertrigo, hypotrichosis and oral mucosal involvement. A
similar phenotype was noted in four members of his family and in three sporadic
cases. Histological examination of oral mucosa and skin samples showed a
psoriasiform pattern, dyskeratotic features and cytoplasmic vacuoles. Expression
of connexins (Cx), desmosomal, adherens junction and cytoskeleton proteins (Cx
26, 32 and 43, desmogleins 1 and 2, plakoglobin, desmoplakins I-II, plakophilin
1, beta-catenin, E-cadherin, keratins, beta-tubulin, vimentin and actin) was
normal. Ultrastructural studies showed a reduced number of desmosomes.
Dyskeratotic cells exhibited internalized gap junctions, long filamentous
inclusions reactive with antikeratin antibodies, and bundles of perinuclear
fibres resembling clear tonofilaments. Genetic analysis in the studied family
excluded the desmosomal cadherins in chromosome 18q12 as candidate genes.
CONCLUSIONS: A diagnosis of hereditary mucoepithelial dysplasia should be
strongly suggested by the triad of non-scarring alopecia, well-demarcated
erythema of oral mucosa and psoriasiform perineal rash, after exclusion of the
clinically related follicular keratosis syndromes. Defective expression of
cytoskeleton elements and/or a modification of mechanisms regulating
junction-cytoskeleton assembly may be primarily responsible for impaired
epithelial cohesion.

DOI: 10.1111/j.1365-2133.2005.06664.x
PMID: 16086741 [Indexed for MEDLINE]

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