Mutation detection of type II hair cortex keratin gene KRT86 in a Chinese Han family with congenital monilethrix / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Monilethrix is an autosomal dominant hair disorder characterized clinically by alopecia and follicular papules. In this study, we collected a Han monilethrix family to detect the mutations in patients and investigated the correlation between the genotype and phenotype of monilethrix.</p><p><b>METHODS</b>In this study, we identified a Chinese family with monilethrix through light microscopic and scanning electron microscopic (SEM) examination. Genomic DNA from peripheral blood samples was prepared. DNA samples from controls and monilethrix patients were subject to polymerase chain reaction (PCR) amplification. Two pairs of primers were used to amplify the seventh exon of KRT86. Mutation screening of the PCR products was detected using direct sequencing.</p><p><b>RESULTS</b>Light microscopic examination showed a regular alternate enlargement and narrow area. SEM examination showed that part of the cuticle of the nodules shed and disappeared gradually in the narrow area with granular protrusions on the surface similar to the erosion-like structure. Parallel longitudinal ridge and groovepattern appeared, and the ridges varied in width, like dead wood. A heterozygous transversion mutation c.1204G > A (p.E402K) in the seventh exon of KRT86 was identified in both patients.</p><p><b>CONCLUSIONS</b>The mutation of extron 7 of KRT86 identified plays a major role in the pathogenesis of this pedigree with monilethrix, and is a mutation hot spot of KRT86. Further research is needed to explore the relationship between the phenotype and the mutation of the type II hair keratin gene KRT86 of monilethrix.</p>

PTCH gene mutations in odontogenic keratocysts / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the frequency, type and distribution of PTCH mutations in odontogenic keratocysts (OKC) and to analyze the molecular pathological relationship between sporadic OKC and OKC associated with nevoid basal cell carcinoma syndrome (NBCCS).</p><p><b>METHODS</b>Genomic DNA was extracted from 8 cases of OKC lesions (4 sporadic OKCs and 4 NBCCS-related OKCs). PTCH gene mutations were detected by PCR-direct sequencing.</p><p><b>RESULTS</b>Six novel PTCH mutations were identified in 6 out of 8 cases (2 sporadic and 4 NBCCS-related OKCs). Two of these were missense mutations leading to substitution of an amino acid residue respectively. The other 4 mutations were identified as insertion or deletion ranging from one single base to 7 bases, three of which caused frame-shift leading to premature truncation of PTCH protein and one resulted in an insertion of 2 amino acid residues. All these identified mutations were novel and have not been previously described.</p><p><b>CONCLUSIONS</b>PTCH gene mutation is a common event in NBCCS-related OKCs and could also be detected in some sporadic OKCs. Abnormalities of PTCH gene may be involved in the pathogenesis of OKC.</p>

Gene mutation detection in a cleidocranial dysplasia family / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study gene mutation in Chinese patients with cleidocranial dysplasia.</p><p><b>METHODS</b>A three generation family with the clinical diagnosis of cleidocranial dysplasia was investigated in present study. Genomic DNA was extracted from peripheral blood samples of each of the family members. Direct sequencing of the PCR products of the coding region of CBFA1 gene was used to identify the mutations.</p><p><b>RESULTS</b>In each patient of the family, a heterozygous missense mutation, cDNA 674 G > A (R225Q), was detected in CBFA1 exon 3. The mutation changed the sequence in runt domain of the protein.</p><p><b>CONCLUSIONS</b>Our findings indicate that mutation in CBFA1 is responsible for the tooth agenesis and other phenotypes of cleidocranial dysplasia in this Chinese family. The mutation detection could be applied in prenatal diagnosis for the family.</p>

The relationship between a nucleotide substitution of S100A8 gene and aggressive periodontitis / 中华口腔医学杂志

<p><b>OBJECTIVES</b>To screen polymorphisms in the upstream region of S100A8 gene and to detect whether the polymorphisms were associated with aggressive periodontitis.</p><p><b>METHODS</b>Thirty aggressive periodontitis patients and twenty-eight healthy controls were recruited for the study with informed consent. All subjects were of Chinese descent and systemically healthy. The regions about 800 bp upstream from the ATG start codon in exon 2 of the S100A8 gene of 10 patients and 8 controls were amplified by polymerase chain reaction (PCR) and analyzed by direct sequencing. A single nucleotide polymorphism (SNP) at 94 bp upstream from the ATG start codon was selected, and then the shorter regions (about 250 bp upstream from the ATG start codon) of the rest subjects were also amplified by PCR and analyzed by direct sequencing. The frequency of the SNP and the distribution of the genotype were detected and compared between the two groups.</p><p><b>RESULTS</b>A nucleotide substitution (A-->G) at 94 bp upstream from the ATG start codon was demonstrated in Chinese, which was in a cis-acting element, named gamma interferon response element (gamma-IRE) in intron 1 of S100A8 gene. All of the subjects that carried the polymorphism were heterozygous. There was no statistically significant difference in the frequency of allele 2 (corresponding to the nucleotide G) between patients and controls (11.7% vs. 17.9%, chi2 = 0.887, P > 0.05). The prevalence of the heterozygous genotype was 23.2% and 35.7% (chi2 = 1.07, P > 0.05) in patients and controls, respectively.</p><p><b>CONCLUSIONS</b>This is the first report that a nucleotide substitution of S100A8 gene was demonstrated in Chinese. The frequencies of allele 2 and heterozygous genotype were lower in patients, but there is no statistically significant difference between the aggressive periodontitis patients and healthy controls in this preliminary study.</p>