Objective To analyze the mutations in keratin 1 (KRT1), KRT9 and KRT10 genes in a Chinese family with epidermolytic palmoplantar keratoderma (EPPK). Methods Clinical data were collected from a family with EPPK. Genomic DNA was extracted from the peripheral blood of 12 family members, including 6 patients and 6 unaffected members, as well as from 50 unrelated normal human controls. PCR was performed to amplify all the exons and flanking sequences of KRT1, KRT9 and KRT10 genes followed by DNA sequencing.Results A missense mutation C.1436T > C was found in the highly conserved helix termination motif of KRT1 gene of all the patients, resulting in a substitution of isoleucine by threonine at position 479 of the KRT1 protein. No mutation was found in the unaffected members or unrelated controls. Conclusions The missense mutation C.1436T > C in K.RT1 gene is likely to be the main cause of the phenotype of EPPK in this family.This is the first report of a pedigree with KRT1 gene mutation-induced EPPK in China.

Objective To detect the steroid sulfatase (STS) gene mutation in a Chinese pedigree with X-linked ichthyosis (XLI). Methods Genomic DNA was extracted from the peripheral blood of 3 affected patients and unaffected members in this family and 50 unrelated healthy volunteers followed by the amplification of the exon 1 and exon 10 of STS gene by PCR. Results Complete deletion of the exon 1 to 10 of STS gene was detected in all the patients in this pedigree with XLI, while no mutation was found in this gene in unaffected members of this family or normal human controls. Conclusion The complete deletion of STS gene is likely to be the main cause of the phenotype of XLI in this family.

Objective To detect mutations in the PTPN11 gene in a family with LEOPARD syndrome (LS).Methods Clinical data were collected from a 7-year-old boy patient with LS.Peripheral blood was obtained from the patient,both of his parents,and 50 healthy controls.All the exons and their flanking sequences of the PTPN11 gene were amplified by PCR followed by direct DNA sequencing.Results A heterozygous missense mutation c.836A ＞ G,which resulted in a substitution of TAT by TGT at codon 279,was found in exon 7 of the PTPN11 gene in the patient.No mutation was detected in the unaffected parents or healthy controls.Conclusion The missense mutation c.836A ＞ G may be the cause of the phenotype of LS in this family.

Objective To identify gene mutations in two families with epidermolytic hyperkeratosis (EHK).Methods Clinical data were collected from two families with EHK.Peripheral blood was isolated from the probands and unaffected family members in the families as well as from 50 healthy controls.PCR was performed to amplify the encoding exons and flanking intron regions of KRT1 and KRT10 genes followed by direct DNA sequencing.Results Two mutations in the KRT10 gene,including a heterozygous acceptor splice site mutation in intron 4 (c.1030-2 A＞G) and a heterozygous missense mutation c.467 G＞A,were identified in the probands of both families,but absent in the unaffected family members or healthy controls.ConclusionThe splice site mutation c.1030-2 A＞G and missense mutation c.467 G＞A might be responsible for the phenotype of EHK in the two families.

Objective:To investigate mutations in the KRT5 gene in a pedigree with Dowling-Degos disease.Methods:Clinical data were collected from the proband, and a survey was conducted in 12 members in 3 generations of the family. Peripheral blood samples were obtained from the proband, 8 family members and 50 unrelated healthy individuals, genomic DNA was extracted for whole-exome sequencing, and sequencing results were compared with the published sequences of human KRT5, POFUT1 and POGLUT1 genes.Results:There were 3 patients in this family, including the proband, his father and deceased grandmother. The proband and his father clinically presented with reticular pigmentation in the skinfolds, especially the chest and abdomen skinfolds. A novel heterozygous nonsense mutation c.165T>A was identified in exon 1 of the KRT5 gene in the proband and his father, but not in other family members or healthy controls. No abnormality was found in the POFUT1 or POGLUT1 gene in any subjects.Conclusion:A novel heterozygous nonsense mutation c.165T>A was identified in the KRT5 gene, and may contribute to the clinical phenotype of the proband and his father with Dowling-Degos disease.