A nonsense mutation in DHTKD1 causes Charcot-Marie-Tooth disease type 2 in a large Chinese pedigree.

Charcot-Marie-Tooth (CMT) disease represents a clinically and genetically heterogeneous group of inherited neuropathies. Here, we report a five-generation family of eight affected individuals with CMT disease type 2, CMT2. Genome-wide linkage analysis showed that the disease phenotype is closely linked to chromosomal region 10p13-14, which spans 5.41 Mb between D10S585 and D10S1477. DNA-sequencing analysis revealed a nonsense mutation, c.1455T>G (p.Tyr485(∗)), in exon 8 of dehydrogenase E1 and transketolase domain-containing 1 (DHTKD1) in all eight affected individuals, but not in other unaffected individuals in this family or in 250 unrelated normal persons. DHTKD1 mRNA expression levels in peripheral blood of affected persons were observed to be half of those in unaffected individuals. In vitro studies have shown that, compared to wild-type mRNA and DHTKD1, mutant mRNA and truncated DHTKD1 are significantly decreased by rapid mRNA decay in transfected cells. Inhibition of nonsense-mediated mRNA decay by UPF1 silencing effectively rescued the decreased levels of mutant mRNA and protein. More importantly, DHTKD1 silencing was found to lead to impaired energy production, evidenced by decreased ATP, total NAD(+) and NADH, and NADH levels. In conclusion, our data demonstrate that the heterozygous nonsense mutation in DHTKD1 is one of CMT2-causative genetic alterations, implicating an important role for DHTKD1 in mitochondrial energy production and neurological development.

Stable isolated metal atoms as active sites for photocatalytic hydrogen evolution.

The process of using solar energy to split water to produce hydrogen assisted by an inorganic semiconductor is crucial for solving our energy crisis and environmental problems in the future. However, most semiconductor photocatalysts would not exhibit excellent photocatalytic activity without loading suitable co-catalysts. Generally, the noble metals have been widely applied as co-catalysts, but always agglomerate during the loading process or photocatalytic reaction. Therefore, the utilization efficiency of the noble co-catalysts is still very low on a per metal atom basis if no obvious size effect exists, because heterogeneous catalytic reactions occur on the surface active atoms. Here, for the first time, we have synthesized isolated metal atoms (Pt, Pd, Rh, or Ru) stably by anchoring on TiO2 , a model photocatalystic system, by a facile one-step method. The isolated metal atom based photocatalysts show excellent stability for H2 evolution and can lead to a 6-13-fold increase in photocatalytic activity over the metal clusters loaded on TiO2 by the traditional method. Furthermore, the configurations of isolated atoms as well as the originality of their unusual stability were analyzed by a collaborative work from both experiments and theoretical calculations.

An SNP of the ZBTB38 gene is associated with idiopathic short stature in the Chinese Han population.

OBJECTIVE: Idiopathic short stature (ISS) refers to extreme short stature without any diagnostic explanation. Recently, three genome-wide association studies discovered associations between the ZBTB38 and adult height in different populations. Therefore, variations in the ZBTB38 might contribute to ISS. Furthermore, one study in Korean population showed that ZBTB38 gene was significantly associated with adult height, but not with ISS. We want to examine whether the variants in ZBTB38 are associated with ISS in Chinese Han. METHODS: A case-control association study was performed in 268 ISS patients and 513 healthy controls from Chinese Han population. Fourteen tag SNPs were selected and genotyped using SNaPshot method. Furthermore, expression of mRNA was quantified by RT-qPCR, and assessment of allelic expression imbalance was conducted with SNaPshot method. RESULTS: Seven ZBTB38 SNPs were significantly associated with ISS by allele tests (rs724016, rs1582874, rs11919556, rs6440006, rs7612543, rs62282002, rs18651435). And five loci were associated with ISS according to genotype (rs11919556, rs16851419, rs6440006, rs62282002, rs18651435). Notably, after applying the stringent Bonferroni correction for multiple testing, one SNP, rs16851435, remained significantly associated by allele and genotype (P = 5·30 × 10⁻4 for allele and P = 0·002 for genotype). Furthermore, the rs16851435 alleles were investigated association with ZTBT38 mRNA expression levels. The G allele showed a higher transcriptional activity than the T allele (P = 0·002). CONCLUSIONS: Our study indicated that the nonsynonymous SNP (rs16851435:T > G,p.Ser319Ala) of ZBTB38 was contributed to susceptibility of ISS in the Chinese Han population.

Single nucleotide polymorphism rs3732860 in the 3'-untranslated region of CYP8B1 gene is associated with gallstone disease in Han Chinese.

BACKGROUND AND AIMS: Gallstone disease (GD) is a common disease of multigenetic origin; however, the major susceptibility loci for GD in human populations remain unidentified. This study aimed to identify the genetic factors contributing to gallstone development in Chinese. METHODS: A genome-wide scan was conducted in 12 Han Chinese GD families to identify linkage loci. The linkage region showing the highest logarithm of odds score encompasses the sterol 12α-hydroxylase gene (CYP8B1). Replication analysis with an independent sample of 192 GD patients and 192 unrelated, matched controls was carried out to verify the associations between CYP8B1 polymorphisms and GD. RESULTS: Three loci (D3S1266, D4S406, and D9S1682) showed suggestive or nominal evidence of linkage in all 12 GD families. The logarithm of odds score of D3S1266 reached 2.71 in the families with late-onset patients. The single nucleotide polymorphism rs3732860 in the 3'-untranslated region of CYP8B1 showed significant association to GD (P = 0.022), and carriers of the A allele had lower risk of GD (odds ratio = 1.46, 95% confidence interval: 1.055-2.034) compared with carriers of the G allele. CONCLUSIONS: The single nucleotide polymorphism rs3732860 in the 3'-untranslated region of the CYP8B1 gene is associated with risk of GD in Chinese Han and appears to be responsible for the observed linkage with D3S1266.

Multiple synostoses syndrome is due to a missense mutation in exon 2 of FGF9 gene.

Fibroblast growth factors (FGFs) play diverse roles in several developmental processes. Mutations leading to deregulated FGF signaling can cause human skeletal dysplasias and cancer.(1,2) Here we report a missense mutation (Ser99Asp) in exon 2 of FGF9 in 12 patients with multiple synostoses syndrome (SYNS) in a large Chinese family. In vitro studies demonstrate that FGF9(S99N) is expressed and secreted as efficiently as wild-type FGF9 in transfected cells. However, FGF9(S99N) induces compromised chondrocyte proliferation and differentiation, which is accompanied by enhanced osteogenic differentiation and matrix mineralization of bone marrow-derived mesenchymal stem cells (BMSCs). Biochemical analysis reveals that S99N mutation in FGF9 leads to significantly impaired FGF signaling, as evidenced by diminished activity of Erk1/2 pathway and decreased beta-catenin and c-Myc expression when compared with wild-type FGF9. Importantly, the binding of FGF9(S99N) to its receptor is severely impaired although the dimerization ability of mutant FGF9 itself or with wild-type FGF9 is not detectably affected, providing a basis for the defective FGFR signaling. Collectively, our data demonstrate a previously uncharacterized mutation in FGF9 as one of the causes of SYNS, implicating an important role of FGF9 in normal joint development.

Functional polymorphisms, altered gene expression and genetic association link NRH:quinone oxidoreductase 2 to breast cancer with wild-type p53.

We hypothesized that NRH:quinone oxidoreductase 2 (NQO2) is a candidate susceptibility gene for breast cancer because of its known enzymatic activity on estrogen-derived quinones and its ability to stabilize p53. We performed case-control studies to investigate the contributions of genetic variants/haplotypes of the NQO2 gene to breast cancer risk. In the first hospital-based study (n = 1604), we observed significant associations between the incidence of breast cancer and a 29 bp-insertion/deletion polymorphism (29 bp-I/D) and the rs2071002 (+237A>C) polymorphism, both of which are located within the NQO2 promoter region. Decreased risk was associated with the D-allele of 29 bp-I/D [odds ratio (OR), 0.76; P = 0.0027] and the +237C-allele of rs2071002 (OR, 0.80; P = 0.0031). Specifically, the susceptibility variants within NQO2 were notably associated with breast carcinomas with wild-type p53 (the most significant P-value: 3.3 x 10(-6)). The associations were successfully replicated in an independent population set (familial/early-onset breast cancer cases and community-based controls, n = 1442). The combined P-values of the two studies (n = 3046) are 3.8 x 10(-7) for 29 bp-I/D and 2.3 x 10(-6) for rs2071002. Furthermore, we revealed potential mechanisms of pathogenesis of the two susceptibility polymorphisms. Previous work has demonstrated that the risk-allele I-29 of 29 bp-I/D introduces transcriptional-repressor Sp3 binding sites. Using promoter reporter-gene assays and electrophoretic-mobility-shift assays, our present work demonstrated that the other risk-allele, +237A-allele of rs2071002, abolishes a transcriptional-activator Sp1 binding site. Furthermore, an ex vivo study showed that normal breast tissues harboring protective genotypes expressed significantly higher levels of NQO2 mRNA than those in normal breast tissues harboring risk genotypes. Taken together, the data presented here strongly suggest that NQO2 is a susceptibility gene for breast carcinogenesis.

The association between the IL-20-1723C→G allele on the 1q chromosome and psoriasis triggered or exacerbated by an upper respiratory tract infection in the Chinese Han population.

BACKGROUND: Psoriasis is a cutaneous disorder of multifactorial etiology influenced by both genetic and environmental factors such as infection. METHODS: We conducted a genome analysis with 20 microsatellite markers spanning the long arm of chromosome 1 in 36 Chinese families with psoriasis and detected evidence for linkage at 1q21 with a nonparametric linkage score of 1.74, p=0.03, and 1q32 with one of 1.84, p=0.03. According to the positional and functional candidate principle, we further investigated the single-nucleotide polymorphisms of the HAX-1 gene (located in 1q21) and IL-20 gene (located in 1q32) in a case-control study including 340 sporadic patients and 199 controls. RESULTS: We determined that the frequency of the G allele of IL-20-1723C→G (rs1713239) was significantly higher among psoriatic patients (38.5% in cases vs. 31.2% in controls, p=0.015, odds ratio, OR=1.39, 95% confidence interval, CI=1.07-1.80). When we stratified our analysis by psoriasis triggered or exacerbated by infection of the upper respiratory tract, a significant difference was detected (42.4% in stratified cases vs. 31.2% in controls, p=0.005, OR=1.63, 95% CI=1.15-2.30). CONCLUSION: We assume that triggered or exacerbated by respiratory tract infection, the population with the G allele of IL-20-1723C→G are predisposed to psoriasis.

Genetic contribution of GADD45A to susceptibility to sporadic and non-BRCA1/2 familial breast cancers: a systematic evaluation in Chinese populations.

Growth arrest and DNA damage-induced 45, alpha (GADD45A) is a candidate breast cancer susceptibility gene because its product participates in DNA repair and it is a downstream gene of p53 and BRCA1, both of which are breast cancer susceptibility genes. We screened germline mutations of GADD45A in 185 non-BRCA1/2 familial breast cancer patients, but no deleterious mutation was found. Seven single-nucleotide-polymorphisms were identified in a subsample. Five common variants (minor allele frequency > 10%) were genotyped for association analyses to scrutinize the relationship between breast cancer and polymorphisms in GADD45A in two independent population sets (total n = 1,861). In the first case-control study (n = 1,457, cases 820, controls 637), a comparison of genotype frequencies between sporadic breast cancer patients and controls indicated the CT/TT-genotypes of +1506C>T and CG/CC-genotypes of +3204G>C were associated with decreased breast cancer risk (adjusted odds ratio (OR), 0.77; 95% confidence interval (CI), 0.62-0.96; and adjusted OR, 0.71; 95%CI, 0.57-0.88, respectively) compared with their wild-type homozygotes. A common haplotype CGTCC was also associated with reduced risk (P = 1.0 x 10(-4)). In a second familial breast cancer patient-based case-control study (n = 404, cases 185, controls 219), although +1506C>T and +3204G>C failed to be validated, the haplotype CGTCC showed a borderline significance. Notably, the combined P-values were robust for +3204G>C (P = 3.1 x 10(-4)) and CGTCC (P = 1.6 x 10(-5)). Moreover, CGTCC was correlated with a higher GADD45A expression in normal breast tissues. In conclusion, although germline mutations of GADD45A is not common in familial breast cancer patients, polymorphisms/haplotypes in GADD45A contribute to breast cancer risk, at least to sporadic breast cancer.

Genetic variants in GSTM3 gene within GSTM4-GSTM2-GSTM1-GSTM5-GSTM3 cluster influence breast cancer susceptibility depending on GSTM1.

Mu class of Glutathione-S-transferase (GSTM) genes arrange in a tandem on chromosome 1p13.3. The relationship between genetic variants in the GSTM1-5 gene cluster and breast cancer is still ambiguous. In the present study, 17 tagging single-nucleotide polymorphisms (SNPs) covering the GSTMs cluster were originally selected and 11 validated SNPs were used for genotyping 921 cases and 711 controls. The association analyses were performed according to the absence or presence of GSTM1. In the GSTM1-/- group, the allele frequency of one SNP in GSTM3 was significantly different between cases and controls (P = 2.0 x 10(-4), corrected P = 0.001), with odds ratio of 1.75 (95% confidence interval, 1.26-2.44). The observed association in the GSTM1-/- group was successfully replicated in an independent population set (familial/early-onset breast cancer cases, n = 267; community-based controls, n = 667). The combined P values were robust (10(-6)) and the false positive report probability (FPRP) values were low. In contrast, no susceptibility allele/haplotype was identified when the GSTM1 gene was present. Based on epidemiological observations, we further identified two genetic variants in the GSTM3 locus accounting for differential expression of GSTM3 in normal breast tissues by such means as altering binding of RNA-pol-II. Protective genotypes were correlated with higher GSTM3 expression levels. In conclusion, SNPs/haplotypes in the GSTM3 gene within the GSTMs gene cluster are likely to contribute to breast cancer risk when the GSTM1 is absent. We infer that GSTM3 catalyzing ability in normal breast tissue might protect against breast carcinogenesis.

The prevalence of PALB2 germline mutations in BRCA1/BRCA2 negative Chinese women with early onset breast cancer or affected relatives.

PALB2 has been recently identified as breast cancer susceptibility gene in western populations. To investigate the contribution of PALB2 mutations to Chinese non-BRCA1/BRCA2 hereditary breast cancer, we screened all coding exons and intron-exon boundaries of PALB2 in 360 Chinese women with early-onset breast cancer or affected relatives from five breast disease clinical centers in China by utilizing PCR-DHPLC and DNA sequencing analysis. Some genetic variants identified in the cases were then studied in 864 normal controls with no personal or family history of breast cancer. Two protein-truncating PALB2 mutations, 751C>T and 1050_1051delAAinsTCT, were identified in three separate families, and 751C>T was a recurrent mutation. Neither of them, however, were present in the controls (P=0.025). All the truncating mutations occurred in exon 4 of PALB2, and there were still three unclassified variants were detected in the same fragment. We found that exon 4 accounted for 44.1% (15/34) of the person-times carrying with any variant in our study. PALB2 mutations were responsible for approximately 1% of Chinese women with early-onset breast cancer and affected relatives. Our results suggested that a detection of exon 4 before the assay of the whole PALB2 gene might be a cost-effective approach to the screening of Chinese population.

Mutation analysis of BRIP1/BACH1 in BRCA1/BRCA2 negative Chinese women with early onset breast cancer or affected relatives.

The proper interaction between BRIP1/BACH1 and BRCA1 protein has been found to be crucial for BRCA1-mediated DNA double-strand break repair and BRIP1/BACH1 mutations were estimated to confer a relative risk for breast cancer of 2.0 in western populations. In Chinese population, BRCA1 mutations could explain a relatively large proportion of inherited breast cancer cases in comparison with BRCA2 mutations, which probably deduced a hypothesis that those genes involved in BRCA1-mediated DNA repair pathway might play a more significant role in the etiology of Chinese breast cancer. To investigate the contribution of BRIP1/BACH1 mutations to the predisposition of Chinese non-BRCA1/BRCA2 hereditary breast cancer, we screened all the coding exons and adjacent intronic splice junction regions of BRIP1/BACH1 in 357 Chinese women with early-onset breast cancer or affected relatives from five different breast disease clinical centers in China, using PCR-DHPLC and DNA sequencing analysis. Some genetic variants identified in the cases were then studied in 864 normal controls with no personal or family history of breast cancer. We found no protein-truncated mutations in our population, while a novel recurrent non-synonymous variant, Q944E, was detected in two independent families in contrast with none in the controls, interestingly, this alteration occurs in the BRCA1 binding domain of the BACH1 protein. Then a further study performed on the two mutation positive families revealed the partial co-segregation of this mutation allele with cancer. The novel alteration Q944E identified in our study possibly represents a rare disease-related allele, nevertheless functional analysis is still warranted to resolve the ability of this altered BACH1 protein to bind BRCA1. Altogether, the results of our study indicated that germline mutations in BRIP1/BACH were extremely rare in Chinese population and there was no evidence for the recommendation of BRIP1/BACH1 for genetic testing in Chinese.

Models for predicting BRCA1 and BRCA2 mutations in Han Chinese familial breast and/or ovarian cancer patients.

PURPOSE: Our aim was to find an appropriate method to estimate the likelihood that a family history of cancer was a result of a mutation in the BRCA1 or BRCA2 genes. We also compared the performance of the established method with three different methods (Couch, Sh-E and BRCApro) to identify an alternative strategy for genetic council targeted to the specified population. PATIENTS AND METHODS: The family history as well as individual information of two hundred unrelated probands who had completed BRCA1 and BRCA2 mutation screening was analyzed to assess the likelihood of a pathogenic mutation. A model was developed by empirical method. The performance of this model was validated in a separate patient cohort compared with BRCApro. RESULTS: Several factors were associated with mutations in univariate analysis and a logistic model was devised to estimate the probability for a proband of harboring a mutation in BRCA1 and/or BRCA2. Using a greater than 10% probability threshold, the highest accuracy was achieved by the established model when compared to other three models, presenting the highest sensitivity, PPV, NPV and area under ROC curve. The empirical model showed a better ROC curve compared to BRCApro in the verification cohort. CONCLUSION: A probability model targeted to Han Chinese population should be a useful tool in the genetic counseling for the specified ethnic. Its ability to predict BRCA2 mutation carriers needs to be improved.

[BRCA1 germ line mutations in Chinese early-onset breast cancer patients].

OBJECTIVE: To investigate the role of disease associated germ line mutations in BRCA1 gene among Chinese early-onset breast cancer patients. METHODS: A total of 188 early-onset breast cancer patients, who were diagnosed with breast cancer before 41-year-old, were enrolled from four breast cancer clinical centers in China. Thirty-nine of them (20.7%) also had family history of breast/ovarian cancer. DNA extracted from lymphocytes was amplified by polymerase chain reaction (PCR) for the entire exons and the splicing sites of BRCA1. Twenty-two of the patients were screened by single strand conformation polymorphism (SSCP), and the other 166 of them were screened by denaturing high performance liquid chromatography (DHPLC). The abnormal fragments recognized were ascertained by DNA direct sequencing. For those samples with the same recurrent mutation, five BRCA1-linked markers (D17S855, D17S1322, D17S1323, D17S1326 and D17S1327) were used for the allelotype analysis. RESULTS: Twelve disease-associated mutations were identified in 15 (8.0%) patients, among which BRCA1 1100delAT and 5589del8 were identified in 3 and 2 patients respectively. Nine (23.1%) of them were identified in those with breast/ovarian cancer family history. The difference of BRCA1 mutation frequency between the patients with and without family history was statistically significant (P=0.001). Allelotype analysis showed the two BRCA1 5589del8 mutation carriers shared the same allelotype in all the 5 STR sites, and two of the three 1100delAT mutation carriers, who came from the northern China, also shared the same allelotype in all the 5 STR sites, which were different from those of the 5589del8 mutation carriers'. CONCLUSION: This is a relatively very large scale multi-hospital-based study of BRCA1 mutations in Chinese early-onset breast cancer patients up to now. It seems reasonable to give genetic consultations and genetic test of BRCA1 gene to early-onset breast cancer patients in China, especially for those with breast/ovarian cancer family history. The two recurrent mutations might be founder mutations of Chinese population. It might be cost-effective to analyze these two mutations before whole gene analysis.

[BRCA1 1100delAT is a recurrent mutation in Chinese women with familial breast cancer].

OBJECTIVE: Previous investigation on BRCA1 gene mutations in thirty-five breast cancer patients with affected relatives in Shanghai identified four germ-line mutations (1100delAT, IVS17-1G > T, IVS21+1G > C and 5640delA). To our knowledge, up to now, no founder mutation in BRCA1 gene has been identified in Chinese mainland population. The aim of this study was to investigate whether there are recurrent mutations or 'founder mutations' in Chinese mainland population. METHODS: Peripheral blood samples were collected from 60 breast cancer patients with at least one first-degree relative affected with breast cancer from Shanghai, Jinan, Qingdao, and Shenyang. DNA extracted from lymphocytes was amplified by polymerase chain reaction (PCR) to analyze the 4 germ-line mutations (1100delAT, IVS17-1G > T, IVS21+1G > C and 5640delA) discovered previously: the amplicons were analyzed by denaturing high-performance liquid chromatography (DHPLC), and those with abnormal chromatographic profiles were confirmed by direct sequencing. Four BRCA1-linked markers were used to do allelotype analysis. RESULTS: Only the 1100delAT mutation in BRCA1 gene recurred in two unrelated individuals. Allelotype analysis showed that the two individuals who carried the 1100delAT mutation shared the same allelotype at 4 sites: D17S855, D17S1322, D17S1326, and D17S1327, which was different from the allelotype of the patients who carried the mutation at the site D17S1322 previously reported in Shanghai population. This recurrent mutation gave an overall prevalence of 3.16% (3/95) in all of our investigated population. A novel mutation, 5589del8, was found in one case. CONCLUSION: Recurrent mutation is found in Chinese mainland familial breast cancer patients for the first time. 1100delAT mutation may be a hotspot in BRCA1 gene in Chinese population. Whether this mutation is a founder mutation in the Northern Chinese community need further investigation.

[CHEK2 c.1100delC may not contribute to genetic background of hereditary breast cancer from Shanghai of China].

OBJECTIVE: To investigate the prevalence of CHEK2 c.1100delC mutation among non-BRCA1/BRCA2 familial/early-onset breast cancer patients in Shanghai. METHODS: One hundred and fourteen non-BRCA1/BRCA2 hereditary breast cancer patients were analyzed, among whom 76 cases had at least one first-degree relative affected with breast cancer and 38 cases were diagnosed as breast cancer below the age of 40 years without family history. The mutation genotyping of CHEK2 c.1100delC were carried out through long-range PCR amplifying of exons 10-14, and followed by amplification of exon 10 and then DNA direct sequencing. RESULTS: No c.1100delC frame-shift mutation was identified in our studied population. One novel missense mutation 1111C>T (p.His371Tyr), located in kinase catalytic domain, was found in 3 familial breast cancer cases but no one in control group. CONCLUSION: CHEK2 c.1100delC is rare variant for Chinese population and may not contribute to predisposition for hereditary breast cancer in Shanghai. Novel variant -1111C>T could be in association with genetic susceptibility to breast cancer. A further study is needed to confirm the results.

[BRCA1 and BRCA2 gene mutations of familial breast cancer from Shanghai in China].

OBJECTIVE: To investigate the prevalence of BRCA1 and BRCA2 gene mutations among breast cancer patients with affected relatives in Shanghai of China. METHODS: Thirty-five breast cancer patients who had at least one first-degree relative affected were analyzed, among whom 13 patients suffered from breast cancer at age of less than 40 years. A comprehensive BRCA1 and BRCA2 mutation analysis was performed through denaturing high-performance liquid chromatography (DHPLC) and subsequent DNA direct sequencing. RESULTS: Four mutations in BRCA1 gene, including 2 novel splice-site mutations (IVS17-1G>T, IVS21+1G>C) and 2 frameshift mutations (1100delAT; 5640delA) were identified. One frameshift mutation (5802delAATT) was detected in exon 11 of BRCA2. Additional 12 novel single nucleotide polymorphisms(SNPs) were detected, including a novel unclassified variant and 7 novel intronic variants in BRCA1, and 4 novel intronic variants in BRCA2, with which all caused no alteration of amino acid coding. The mutation frequency of BRCA1 and BRCA2 in patients with family history was 11.4% and 2.9%, respectively. CONCLUSION: Two novel mutations in BRCA1 may be mutations characterized to familial breast cancer of Chinese Shanghai population. The BRCA2 may contribute to mutation less than BRCA1 in familial breast cancer. Our data contribute to information on mutation spectrum of BRCA gene in Chinese population and also offer a recommended screening mode for clinical genetic testing policy in China.

[Effect of R264C polymorphism in CYP19A1 gene on BRCA1/2-negative hereditary breast cancer from Shanghai population of China].

OBJECTIVE: Aromatase, encoded by CYP19A1, play an important role in estrogens biosynthesis from androgens. The present study is to investigate effect of R264C single nucleotide polymorphism in CYP19A1 gene on genetic susceptibility for hereditary breast cancer without BRCA1/2 mutant. METHODS: One hundred and fourteen BRCA1/2 -negative hereditary breast cancer patients from independent families and 121 age-matched healthy control subjects were analyzed. Genotype analysis was performed through polymerase chain reaction (PCR) and then DNA direct sequencing. The odd-ratios (OR) and 95% confidence intervals (CI) were calculated by unconditional Logistic regression model. RESULTS: The frequency of R264C single nucleotide polymorphism CC, CT and TT genotype in case group and controls was 84(77.8%), 22(20.4%), 2(1.8%) and 87(77.7%), 24(21.4%), 1(0.9%), respectively. CT genotype (OR=1.16, 95%CI: 0.53-2.55) and TT genotype (OR=1.44, 95%CI: 0.12-17.15) did not confer a significantly increased risk for breast cancer. No significant association was found between T allele and susceptibility for breast cancer under analysis according to menopausal status and body mass index. CONCLUSION: R264C polymorphism in CYP19A1 gene is not a candidate locus for low penetrance breast cancer susceptibility in Shanghai group of Chinese population and not recommended in clinical genetic test. Homozygous T allele of R264C is not common in Shanghai group of Chinese population.

[Prevalence of Val158Met polymorphism in COMT gene on non-BRCA1/2 hereditary breast cancer].

OBJECTIVE: To explore the prevalence of Val158Met polymorphism in Catechol-O-methyltransferase (COMT) gene and its effect on genetic susceptibility for breast cancer in Shanghai population. METHODS: A total of 114 patients with BRCA1/BRCA 2 negative hereditary breast cancer from independent families and 121 age-matched healthy controls were analyzed. Genotype analysis was conducted by polymerase chain reaction (PCR) and then DNA direct sequencing. The odd ratios (OR) and 95% confidence intervals (CI) were calculated by unconditional logistic regression model. RESULTS: The frequency of Val158Met polymorphism GG, GA and AA genotype in case group and control was 0.58 (65), 0.32 (36), 0.10 (11) and 0.60 (66), 0.35 (41), 0.03 (3), respectively. The frequency of allele-containing genotypes is significantly higher in early-onset breast cancer patients (0.57) than in familial ones (0.35). Compared with GG (Val/Val) genotype, AA (Met/Met) genotype confers a significantly increased risk for breast cancer (adjusted OR = 3.15; 95% CI, 0.70 - 14.19), especially among premenopausal women (adjusted OR = 9.98; 95% CI, 1.00 - 99.64). Borderline significantly association was found between AA genotype (adjusted OR = 7.57; 95% CI, 0.57 - 101.28) and susceptibility for breast cancer in BMI < or = 23 kg/m(2) group. CONCLUSIONS: Val158Met polymorphism in COMT gene could be a candidate for low penetrance breast cancer susceptibility in Shanghai population, especially among premenopausal women and early-onset breast cancer patients.

[Study on the position of genes responsible for gallstone disease in Chinese population].

OBJECTIVE: To search the susceptibility genes of gallstone disease in Chinese population. METHODS: A genome wide scan was performed in twelve families with gallstone disease using fluorescence-labeled microsatellite markers. Genehunter and Batchlink of Linkage package were used for non- parameter and parameter linkage analysis to search the linkage loci on chromosomes. RESULTS: Four loci of D3S1266, D4S406, D9S1682 and D11S902 showed suggestive evidence for linkage. nonparametric linkage analysis (NPL)-score of D4S406 and D9S1682 was 1.77 (P = 0.05) and 1.92 (P = 0.04) respectively. The corresponding logarithm of the odds ratio (LOD)-score of D3S1266, D9S1682 were 1.35 and 2.07, and showed a rise of LOD-score from 1.35 to 2.71, 2.07 to 2.40 respectively when families with later-found patients or with higher triglyceride level were analyzed alone. Transmitted disequilibrium test of D11S902 showed a P-value of 0.0027. CONCLUSIONS: Chromosome 3, 4, 9 and 11 may contain genes involved in gallstone disease in Chinese population, and chromosome 3, 9 may hide genes that are liked to gallstone disease in families with later-found patients or with higher triglyceride concentration.

Two closely linked variations in actin cytoskeleton pathway in a Chinese pedigree with disseminated superficial actinic porokeratosis.

BACKGROUND: Disseminated superficial actinic porokeratosis (DSAP) is an uncommon autosomal dominant chronic keratinization disorder, characterized by multiple superficial keratotic lesions surrounded by a slightly raised keratotic border. Recently, SSH1 was identified as the DSAP candidate gene. OBJECTIVE: Our purpose was to determine the locus of DSAP and identify the candidate gene(s) of the disease. METHODS: Genome-wide scanning and linkage analysis were performed in a 6-generation Chinese family with DSAP. The coding exons and promoter region of the candidate genes were screened for the nucleotide variations. RESULTS: A missense mutation (p.Ser63Asn) in SSH1 and a variation (dbSNP3759383: G>A) in the promoter region of ARPC3 were closely linked with DSAP in the pedigree. CONCLUSION: Both SSH1 and ARPC3 are involved in the actin cytoskeleton pathway and interacted with adherent junctions in the epidermal cells. We suggested that cytoskeleton disorganization in epidermal cells was likely associated with the pathogenesis of DSAP.