Compound heterozygosity for new splice site mutations in the plakophilin 1 gene (PKP1) in a Chinese case of ectodermal dysplasia-skin fragility syndrome.

Ectodermal dysplasia-skin fragility syndrome is a rare autosomal recessive inherited disease characterized by skin fragility, nail dystrophy and hyperkeratosis of palms and soles. Skin biopsy shows the loss of cell adhesion and the decrease of desmosomes in number and size. Mutations in PKP1 have been found to be the underlying cause of the syndrome. We report here a Chinese case of ectodermal dysplasia-skin fragility syndrome. Mutation analysis revealed compound heterozygosity for mutations in PKP1 of the proband. A new splice site mutation (c.1053 T>A+c.1054+1 G>T) near the 3' end of exon 5 and at the donor end of intron 5 on one allele was transmitted from the proband's mother. Another new splice site mutation (c.1835-2 A>G) near the acceptor end of intron 10 originated from her father. The absence of the mutant mRNA and plakophilin 1 protein in the proband's skin may result from the mechanism of nonsense-mediated mRNA decay induced by premature stop codons in PKP1 transcripts due to the two splice site mutations.