[A novel keratin 17 gene mutation in a Chinese pedigree of delayed-onset pachyonychia congenita type II].
OBJECTIVE
To detect the keratin 17 gene mutation in a Chinese pedigree of typical delayed-onset pachyonychia congenita type II (PC-II) and to explore the relationship between the genetic mutation and the phenotype of PC-II.


METHODS
The DNA was extracted from the blood samples of 19 patients with PC-II in four generations in the pedigree, 1 unaffected member of the pedigree, and 50 un-related normal persons. Nested PCR was used to amplify the mutation hot spot in the exon 1 of keratin 17 gene. The PCR products were directly sequenced to detect the mutation.


RESULTS
Sequencing of the PCR products revealed that the codon 109 (AAC) was mutated as GAC in the nine affected members of the pedigree, causing the substitution of asparagine by aspartic acid in codon 109 (N109D) located in the 1A domain of keratin 17 gene. No such mutation was found in the unaffected member of the pedigree and the 50 unrelated controls.


CONCLUSIONS
The novel missense mutation (N109D) located in the second half of 1A domain of keratin 17 gene underlies the affected members' phenotype, delayed-onset pachyonychia congenita type II.
Feng
Yi-guo
YG
Department of Dermatology, the Second Hospital, Xi'an Jiaotong University, Xi'an 710004, China.
Xiao
Sheng-xiang
SX
Li
Li
L
Wang
Jun-min
JM
Tan
Sheng-shun
SS
Shi
Yao-zhou
YZ
D017668:Age of Onset; D004476:Ectodermal Dysplasia / Q000235:genetics*; D006801:Humans; D007633:Keratins / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D016133:Polymerase Chain Reaction; D012871:Skin Diseases / Q000235:genetics*
D007633:Keratins