A7445G mtDNA mutation present in a Portuguese family exhibiting hereditary deafness and palmoplantar keratoderma

Authors

  • H Caria,

    1. Centre of Genetics and Molecular Biology, University of Lisbon, Instituto de Ciênca Aplicada e Tecnologia, Edificio ICAT, Campus da FCUL, Campo Grande, 1749-016 Lisbon, Portugal,
    2. Higher School of Health, Polytechnic Institut of Setúbal, Largo Defensores de Chaves, Setúbal,
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  • T Matos,

    1. Centre of Genetics and Molecular Biology, University of Lisbon, Instituto de Ciênca Aplicada e Tecnologia, Edificio ICAT, Campus da FCUL, Campo Grande, 1749-016 Lisbon, Portugal,
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  • R Oliveira-Soares,

    1. University Clinic of Dermatology, Av. Egas Moniz, 1600 Lisbon, Portugal,
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  • AR Santos,

    1. Centre of ORL, University of Lisbon, Av. Egas Moniz, 1600 Lisbon, Portugal,
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  • I Galhardo,

    1. Centre of ORL, University of Lisbon, Av. Egas Moniz, 1600 Lisbon, Portugal,
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  • L Soares-Almeida,

    1. University Clinic of Dermatology, Av. Egas Moniz, 1600 Lisbon, Portugal,
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  • O Dias,

    1. Centre of ORL, University of Lisbon, Av. Egas Moniz, 1600 Lisbon, Portugal,
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  • M Andrea,

    1. Centre of ORL, University of Lisbon, Av. Egas Moniz, 1600 Lisbon, Portugal,
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  • C Correia,

    1. Centre of Genetics and Molecular Biology, University of Lisbon, Instituto de Ciênca Aplicada e Tecnologia, Edificio ICAT, Campus da FCUL, Campo Grande, 1749-016 Lisbon, Portugal,
    2. Faculty of Sciences, University of Lisbon, Campo Grande Ed. C2, 1700-016 Lisbon, Portugal.
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  • G Fialho

    Corresponding author
    1. Centre of Genetics and Molecular Biology, University of Lisbon, Instituto de Ciênca Aplicada e Tecnologia, Edificio ICAT, Campus da FCUL, Campo Grande, 1749-016 Lisbon, Portugal,
    2. Faculty of Sciences, University of Lisbon, Campo Grande Ed. C2, 1700-016 Lisbon, Portugal.
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* Corresponding author, Centre of Genetics and Molecular Biology, University of Lisbon, Instituto de Ciênca Aplicada e Tecnologia, Edificio ICAT, Campus da FCUL, Campo Grande, 1749-016 Lisbon, Portugal, tel. +351 21 7904787; fax +351 21 7954288; E-mail: gfialho@fc.ul.pt

ABSTRACT

Mitochondrial DNA (mtDNA) A7445G point mutation has been shown to be responsible for familial nonepidermolytic palmoplantar keratoderma (NEPPK) associated with deafness without any additional features. To date, only a few cases have been described. We report a Portuguese pedigree presenting an inherited combination of NEPPK and sensorineural deafness compatible with maternal transmission. Clinical expression and age of onset of NEPPK and deafness were variable. Normal expression patterns of epidermal keratins and filaggrin, intercellular junction proteins including connexin 26, loricrin and cornified envelope proteins, were observed. Molecular analysis revealed that all the affected members, previously screened for Cx26 mutations with negative results, presented the mtDNA A7445G point mutation in the homoplasmic form. To our knowledge, this is the fifth family in whom inherited NEPPK and hearing loss are related to this mitochondrial mutation.

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