A7445G mtDNA mutation present in a Portuguese family exhibiting hereditary deafness and palmoplantar keratoderma.
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.
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.
H
H
Caria
T
T
Matos
R
R
Oliveira-Soares
A R
AR
Santos
I
I
Galhardo
L
L
Soares-Almeida
O
O
Dias
M
M
Andrea
C
C
Correia
G
G
Fialho
D000328:Adult; D000072259:Connexin 26; D017630:Connexins; D004272:DNA, Mitochondrial / Q000235:genetics*; D003937:Diagnosis, Differential; D005260:Female; D000091344:Filaggrin Proteins; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007645:Keratoderma, Palmoplantar / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D010375:Pedigree; D017354:Point Mutation; D011174:Portugal; D035781:Siblings; D044465:White People / Q000235:genetics
D017630:Connexins; D004272:DNA, Mitochondrial; C000717249:FLG protein, human; D000091344:Filaggrin Proteins; C000607042:GJB2 protein, human; D000072259:Connexin 26