Tracing the origins of Hakka and Chaoshanese by mitochondrial DNA analysis

Analysis of Risk Factors Associated with Gestational Diabetes Mellitus: A Retrospective Case-Control Study

Objective

Gestational diabetes mellitus (GDM) is a complication of abnormal glucose tolerance during pregnancy, with incidence is on the rise. There are inconsistent results on the risks of GDM and it has not been reported in our region. The purpose of this study is to explore the risk factors of GDM.

Methods

A total of 383 pregnant women were analyzed, including 67 (17.5%) pregnant women with GDM and 316 (82.5%) with normal glucose tolerance (NGT). The relationship of personal history, family history and reproductive history of pregnant women, the levels of alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG), inflammatory markers in blood cell analysis at the first prenatal examination, and fetal ultrasound indices and the risk of GDM were analyzed.

Results

The fetal biparietal diameter, head circumference, and femur length were negatively correlated with HCG level, but not inflammatory markers. The proportion of pregnant women aged ≥30 years old, body mass index (BMI) in early pregnancy≥24.0 kg/m2, history of polycystic ovary syndrome (PCOS), cesarean section, adverse pregnancy, and oral contraceptive use, and pregnant women who conceived through assisted reproduction in GDM group were higher than those in NGT group. Logistic regression analysis showed that age of pregnant woman ≥30 years old (≥30 vs <30 years old, odds ratio (OR): 2.142, 95% confidence interval (CI): 1.183-3.878, p=0.012), BMI≥24.0 kg/m2 (≥24.0 kg/m2 vs 18.5-23.9 kg/m2, OR: 1.887, 95% CI: 1.041-3.420, p=0.036), history of adverse pregnancy (yes vs no, OR: 1.969, 95% CI: 1.022-3.794, p=0.043), and history of oral contraceptive use (yes vs no, OR: 2.868, 95% CI: 1.046-7.863, p=0.041) were associated with GDM.

Conclusion

Age of pregnant woman ≥30 years old, BMI≥24.0 kg/m2, history of adverse pregnancy and oral contraceptive use were independent risk factors for GDM.

Aldehyde Dehydrogenase 2 rs671 G/A and a/A Genotypes are Associated with the Risk of Acute Myocardial Infarction

Background

Aldehyde dehydrogenase 2 (ALDH2) is a key catalytic enzyme involved in the aldehyde metabolism that plays an important role in the occurrence and development of acute myocardial infarction (AMI). However, the relationship of ALDH2 polymorphism and susceptibility to AMI may differ among different regions and populations, and it has not yet been reported in Hakka population. The purpose of the present study was to investigate it in this population.

Methods

Four hundred and nineteen AMI patients and 636 individuals without AMI were included in the present study. The ALDH2 rs671 polymorphism was genotyped using polymerase chain reaction (PCR)-microarray. Differences in ALDH2 rs671 genotypes and alleles between patients and controls were compared, and the relationship between ALDH2 rs671 genotypes and AMI risk was analyzed.

Results

Patients with AMI had a lower frequency of ALDH2 rs671 G/G genotype (43.2% vs 52.7%, p=0.003), and a higher G/A genotype (45.6% vs 38.5%, p=0.025) than controls. And AMI patients had a lower frequency of ALDH2 rs671 G allele (66.0% vs 71.9%), and a higher A allele (34.0% vs 28.1%) (p=0.004) than controls. Logistic regression analysis showed that overweight (body mass index (BMI)≥24.0 kg/m2 vs BMI 18.5-23.9 kg/m2: odds ratio (OR) 2.046, 95% confidence interval (CI): 1.520-2.754, p<0.001), history of hypertension (yes vs no: OR 3.464, 95% CI: 2.515-4.770, p<0.001), ALDH2 rs671 G/A genotype (G/A vs G/G: OR 1.476, 95% CI: 1.102-1.976, p=0.009), and A/A genotype (A/A vs G/G: OR 1.656, 95% CI: 1.027-2.668, p=0.038) maybe the independent risk factors for AMI.

Conclusion

Overweight (BMI≥24.0 kg/m2), a history of hypertension, and ALDH2 rs671 G/A or A/A genotypes increased the risk of developing AMI in Hakka population.

Apolipoprotein E E3/E4 genotype is associated with an increased risk of premature coronary artery disease

OBJECTIVE

Dyslipidemia is one of the causes of coronary heart disease (CAD), and apolipoprotein E (APOE) gene polymorphism affects lipid levels. However, the relationship between APOE gene polymorphisms and premature CAD (PCAD, male CAD patients with ≤ 55 years old and female with ≤ 65 years old) risk had different results in different studies. The aim of this study was to assess this relationship and to further evaluate the relationship between APOE gene polymorphisms and PCAD risk in the Hakka population.

METHODS

This study retrospectively analyzed 301 PCAD patients and 402 age matched controls without CAD. The APOE rs429358 and rs7412 polymorphisms were genotyped by polymerase chain reaction (PCR) -chip technique. The distribution of APOE genotypes and alleles between the case group and the control group was compared. The relationship between APOE genotypes and PCAD risk was obtained by logistic regression analysis.

RESULTS

The frequency of the APOE ɛ3/ɛ4 genotype (18.9% vs. 10.2%, p = 0.001) and ε4 allele (11.1% vs. 7.0%, p = 0.007) was higher in the PCAD patients than that in controls, respectively. PCAD patients with ɛ2 allele had higher TG level than those with ɛ3 allele, and controls carried ɛ2 allele had higher HDL-C level and lower LDL-C level than those carried ɛ3 allele. Regression logistic analysis showed that BMI ≥ 24.0 kg/m2 (BMI ≥ 24.0 kg/m2 vs. BMI 18.5-23.9 kg/m2, OR: 1.763, 95% CI: 1.235-2.516, p = 0.002), history of smoking (Yes vs. No, OR: 5.098, 95% CI: 2.910-8.930, p < 0.001), ɛ3/ɛ4 genotype (ɛ3/ɛ4 vs. ɛ3/ɛ3, OR: 2.203, 95% CI: 1.363-3.559, p = 0.001), ε4 allele (ε4 vs. ε3, OR: 2.125, 95% CI: 1.333-3.389, p = 0.002), and TC level (OR: 1.397, 95% CI: 1.023-1.910, p = 0.036) were associated with PCAD.

CONCLUSIONS

In summary, BMI ≥ 24.0 kg/m2, history of smoking, APOE ɛ3/ɛ4 genotype, and TC level were independent risk factors for PCAD. It means that young individuals who are overweight, have a history of smoking, and carried APOE ɛ3/ɛ4 genotype had increased risk of PCAD.

BRCA1 and BRCA2 germline mutations in Chinese Hakka breast cancer patients

OBJECTIVE

To investigate the prevalence of BRCA1/2 gene variants and evaluate the clinical and pathological characteristics associated with these variants in Chinese Hakka breast cancer patients.

METHODS

A total of 409 breast cancer patients were analyzed based on next-generation sequencing results, with 337 categorized as non-carriers and 72 as carriers of BRCA1/2 variants. Data on the patients' BRCA1/2 gene mutation status, clinical and pathological characteristics, as well as menstrual and reproductive information, were collected, analyzed, compared, and tabulated. Logistic regression analysis was performed to explore the relationship between clinical characteristics and pathogenic variants.

RESULTS

Among the patients, 72 were identified as carriers of pathogenic or likely pathogenic variants in BRCA1/2, while 337 had likely benign or benign mutations. The BRCA1 c.2635G > T (p. Glu879*) variant was detected at a high frequency, accounting for 12.5% (4/32) of the BRCA1 mutations, while the c.5164_5165del (p.Ser1722Tyrfs*4) variant was common among the BRCA2 mutations, accounting for 17.5% (7/40). It was observed that a higher proportion of BRCA1 carriers had the triple-negative breast cancer subtype, whereas more BRCA2 carriers exhibited estrogen receptor (ER) + and progesterone receptor (PR) + subtypes. Multivariate logistic regression analysis revealed that a family history of cancer (OR = 2.36, 95% CI = 1.00-5.54), bilateral cancer (OR = 4.78, 95% CI 1.61-14.20), human epidermal growth factor receptor 2 (HER2)- (OR = 8.23, 95% CI 3.25-20.84), and Ki67 ≥ 15% (OR = 3.88, 95% CI 1.41-10.65) were associated with BRCA1/2 mutations, with the age at diagnosis, age at menarche, and premenopausal status serving as covariates.

CONCLUSIONS

The most common pathogenic variant of the BRCA1 and BRCA2 in breast cancer patients was c.2635G > T and c.5164_5165del, respectively. Additionally, a family history of cancer, bilateral cancer, HER2-, and Ki67 ≥ 15% were identified as independent predictors of BRCA1/2 pathogenic variants.

KRAS/NRAS Mutations Associated with Distant Metastasis and BRAF/PIK3CA Mutations Associated with Poor Tumor Differentiation in Colorectal Cancer

Background

The occurrence, progression, and prognosis of colorectal cancer (CRC) are regulated by EGFR-mediated signaling pathways. However, the relationship between the core genes (KRAS/NRAS/BRAF/PIK3CA) status in the signaling pathways and clinicopathological characteristics of CRC patients in Hakka population remains controversial.

Methods

Patients were genotyped for KRAS (codons 12, 13, 61, 117, and 146), NRAS (codons 12, 61, 117, and 146), BRAF (codons 600), and PIK3CA (codons 542, 545 and 1047) mutations. Clinical records were collected, and clinicopathological characteristic associations were analyzed together with mutations of studied genes.

Results

Four hundred and eight patients (256 men and 152 women) were included in the analysis. At least one mutation in the four genes was detected in 216 (52.9%) patients, while none was detected in 192 (47.1%) patients. KRAS, NRAS, BRAF, and PIK3CA mutation status were detected in 190 (46.6%), 11 (2.7%), 10 (2.5%), 34 (8.3%) samples, respectively. KRAS exon 2 had the highest proportion (62.5%). Age, tumor site, tumor size, lymphovascular invasion, and perineural invasion were not associated with gene mutations. KRAS mutations (adjusted OR 1.675, 95% CI 1.017-2.760, P=0.043) and NRAS mutations (adjusted OR 5.183, 95% CI 1.239-21.687, P=0.024) appeared more frequently in patients with distant metastasis. BRAF mutations (adjusted OR 7.224, 95% CI 1.356-38.488, P=0.021) and PIK3CA mutations (adjusted OR 3.811, 95% CI 1.268-11.455, P=0.017) associated with poorly differentiated tumor.

Conclusion

KRAS/NRAS mutations are associated with distant metastasis and BRAF/PIK3CA mutations are associated with poor tumor differentiation in CRC. And the results provided a better understanding between clinicopathological characteristics and gene mutations in CRC patients.

Genetic polymorphism and variability in the Guangdong Hakka, Teochew, and Cantonese groups: A comprehensive analysis of 19 X-STRs

BACKGROUND

X chromosomeshort tandem repeat (X-STR) loci are playing an increasingly important role inforensic work, identifying female traces in male contamination and explainingcomplex kinship analyses.

METHODS

In this study, we analyzed thegenetic polymorphism of 19 X-STR loci in the Guangdong Hakka, Teochew and Cantonese groups, respectively, aswell as in the Guangdong Hakka, Teochew andCantonese pooled Han. The genetic diversity and forensic characteristics of the19 X-STRs and 7 linkage groups were investigated, respectively.

RESULTS

The experiments showed that the genetic diversity (GD) and polymorphism information content (PIC) in the pooledGuangdong Han ranged from 0.5320 to 0.9234 and 0.4369 to 0.9171, respectively, and the cumulative power of discrimination for males (PDM), power of discrimination for females (PDF) and mean paternity exclusion chance (MEC) were higher than 0.9999999, indicating that the 19 X-STRs had high geneticpolymorphism and discriminatory power. Genetic differences among Chinese Hansubgroups and among different Chinese populations were investigated byphylogenetic reconstruction and principal component analysis (PCA), respectively. Genetic analyses based on neighbor-joining (NJ) tree and principal component analysis plot showed that Cantonese, Teochew and Hakka were closely genetically related, and different populations with closer linguistic components had more genetic affinity.

CONCLUSIONS

This study adds to the forensic X-STR database and demonstrates the forensic efficiency of 19 X-STRs for the Hakka, Teochewand Cantonese populations in Guangdong, and the pooled Han of Hakka, Teochewand Cantonese people in Guangdong.

Prevalence of hepatitis B virus infection among pregnant women in the mountainous regions of southern China: A retrospective single-center study

BACKGROUND

Hepatitis B virus (HBV) infection remains a major public health issue worldwide. Moreover, its prevalence varies significantly in different geographic areas of China. The current study aimed to assess the prevalence of HBV infection among Hakka pregnant women in Meizhou, a remote mountainous region in southern China.

METHODS

This research was performed between January 2015 and December 2020. In total, 16,727 pregnant women receiving antenatal care at Meizhou People's Hospital were included in the analysis. All pregnant women were screened for serum HBV markers.

RESULTS

The prevalence rates of hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody positivity among the participants were 11.74% (n = 1964) and 48.00% (n = 8029), respectively. The overall prevalence rates of susceptibility to infection, HBV immunity, previous/occult infection, inactive HBsAg carrier, and active infection were 36.16%, 33.61%, 16.94%, 8.11%, and 2.30%, respectively. According to age distribution, the prevalence rate of HBsAg positivity elevated concomitantly with increasing age (p < 0.001). From 2015 to 2020, the prevalence rate of HBsAg positivity decreased from 14.50% to 8.19% and that of hepatitis B pre-core antigen positivity from 4.42% to 2.31%. In addition, pregnant women with HBsAg-positive status were more likely to present with gestational diabetes, thrombocytopenia, and anemia than those with HBsAg-negative status.

CONCLUSION

The HBV infection rate remains high among pregnant women in the indigenous Hakka population in southern China. To prevent vertical transmission, cautious surveillance of maternal HBV infection status should be considered in Hakka pregnant women in Meizhou.

ALDH2 gene rs671 G > a polymorphism and the risk of colorectal cancer: A hospital-based study

BACKGROUND

The susceptibility to some cancers is linked to genetic factors, such as aldehyde dehydrogenase 2 (ALDH2) polymorphisms. The relationship between ALDH2 rs671 and colorectal cancer (CRC) is not clear in Hakka population.

METHODS

Between October 2015 and December 2020, a total of 178 CRC patients and 261 controls were recruited. ALDH2 rs671 was genotyped in these subjects, medical records (smoking history, drinking history and blood cell parameters) were collected, and the relationship between these information and CRC was analyzed.

RESULTS

The proportion of the ALDH2 rs671 G/G, G/A, and A/A genotype was 48.3%, 44.4%, and 7.3% in patients; 62.1%, 34.1%, and 3.8% in controls, respectively. The difference of ALDH2 genotypes distribution between cases and controls was statistically significant (p = 0.011). The higher percentage of smokers and alcoholics, higher level of neutrophil to lymphocyte ratio (NLR), platelet count, and platelet to lymphocyte ratio (PLR), and lower level of lymphocyte count, lymphocyte to monocyte ratio (LMR), and mean hemoglobin concentration were observed in patients. Logistic regression analysis indicated that ALDH2 rs671 G/A genotype (G/A vs. G/G) (adjusted OR 1.801, 95% CI 1.160-2.794, p = 0.009) and A/A genotype (A/A vs. G/G) (adjusted OR 2.630, 95% CI 1.041-6.645, p = 0.041) in the co-dominant model, while G/A + A/A genotypes (G/A + A/A vs. G/G) (adjusted OR 1.883, 95% CI 1.230-2.881, p = 0.004) in the dominant model were risk factors for CRC.

CONCLUSIONS

Individuals carrying ALDH2 rs671 A allele (G/A, A/A genotypes) may be at increased risk of colorectal cancer.

Germline variants profiling of BRCA1 and BRCA2 in Chinese Hakka breast and ovarian cancer patients

Objective

To investigate the prevalence and spectrum of BRCA1 and BRCA2 mutations in Chinese Hakka patients with breast and ovarian cancer.

Methods

A total of 1,664 breast or ovarian cancer patients were enrolled for genetic testing at our hospital. Germline mutations of the BRCA gene were analysed by next-generation sequencing, including the coding regions and exon intron boundary regions.

Results

The 1,664 patients included 1,415 (85.04%) breast cancer patients and 245 (14.72%) ovarian cancer patients, while four (0.24%) patients had both the breast and ovarian cancers. A total of 151 variants, including 71 BRCA1 variants and 80 BRCA2 variants, were detected in the 234 (14.06%) patients. The 151 variants included 58 pathogenic variants, 8 likely pathogenic variants, and 85 variants of unknown significance (VUS). A total of 56.25% (18/32) and 65.38% (17/26) of pathogenic variants (likely pathogenic variants are not included) were distributed in exon 14 of BRCA1 and exon 11 of BRCA2, respectively. The most common pathogenic variants among this Hakka population are c.2635G > T (p.Glu879*) (n = 7) in the BRCA1 gene and c.5164_5165del (p.Ser1722Tyrfs*4) (n = 7) in the BRCA2 gene among the Hakka population. A hotspot mutation in the Chinese population, the BRCA1 c.5470_5477del variant was not found in this Hakka population. The prevalence and spectrum of variants in the BRCA genes in the Hakka patients are different from that in other ethnic groups.

Conclusions

The most common pathogenic variant in this population is c.2635G > T in the BRCA1 gene, and c.5164_5165delAG in the BRCA2 gene in this population. The prevalence and spectrum of variants in the BRCA1 and BRCA2 genes in the Hakka patients from southern China are different from those in other ethnic groups.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09943-0.

ALDH2 Polymorphism rs671 *1/*2 Genotype is a Risk Factor for the Development of Alcoholic Liver Cirrhosis in Hakka Alcoholics

Background

Alcoholics are prone to alcoholic cirrhosis (ALC). Aldehyde dehydrogenase 2 (ALDH2) is involved in alcohol metabolism. Herein, the relationship between ALDH2 genotypes and ALC was analyzed among Hakka alcoholics in southern China.

Methods

A total of 213 alcoholics and 214 non-alcoholics were included in the study. The ALDH2 gene rs671 polymorphism was analyzed, life history, disease history, and auxiliary examination results of these participants were collected.

Results

The alcoholics had higher level of total serum protein, and serum globulin, lower level of serum albumin, serum albumin/globulin ratio, serum prealbumin, neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), and platelet-to-lymphocyte ratio (PLR) than non-alcoholics. In the 213 alcoholics, 180 developed ALC. There were 206 non-ALC persons in the 214 non-alcoholics. The proportion of the ALDH2 rs671 G/G homozygous (*1/*1) was significantly lower in ALC patients (83.3%) than that of other groups (100.0% in non-ALC in alcoholics, 95.6% in non-ALC in non-alcoholics), while the proportion of the G/A heterozygous (*1/*2) was significantly higher in ALC patients (16.7%) than that of other groups (0% in non-ALC in alcoholics, 4.4% in non-ALC in non-alcoholics). Logistic regression analysis indicated that participants with low level of NLR (adjusted OR 5.543, 95% CI 2.964–10.368, P<0.001), LMR (adjusted OR 9.256, 95% CI 4.740–18.076, P<0.001), and PLR (adjusted OR 6.047, 95% CI 3.372–10.845, P<0.001), and ALDH2 G/A genotype (adjusted OR 6.323, 95% CI 2.477–16.140, P<0.001) had a significantly higher risk of ALC.

Conclusion

ALDH2 polymorphism rs671 *1/*2 genotype is a potential risk factor for the development of ALC among Hakka alcoholics.

The Features of BRCA1 and BRCA2 Germline Mutations in Hakka Ovarian Cancer Patients: BRCA1 C.536 A>T Maybe a Founder Mutation in This Population

Objective

To investigate the frequencies of BRCA1 and BRCA2 mutations in Chinese Hakka patients with ovarian cancer.

Methods

The protein coding regions and exon intron boundary regions of the BRCA gene were sequenced using genomic DNA isolated from the lymphocytes of patients with next-generation sequencing. The patients’ family history and clinical records were collected.

Results

A total of 195 patients with ovarian cancer were included in the study, and 52 distinct variants of the BRCA gene were identified. It was found that 64 patients (64/195, 32.8%) had BRCA gene mutations, including 32 patients (50.0%) with BRCA1 mutation, 27 patients (42.2%) with BRCA2 mutation, and 5 patients (7.8%) with both mutations. Furthermore, 22 pathogenic mutations were detected in 26 patients, 2 likely pathogenic variants in 2 patients, 12 variants of uncertain significance in 20 patients, and 16 likely benign variants in 24 patients. The mutations were mainly found to occur in exons 8, 14, and 17 of BRCA1 and exons 10, 11, 14, and 15 of BRCA2. The results showed that the BRCA genes possess different mutation hotspots in different ethnic groups. In addition, recurrent mutations were noted in many patients. BRCA1 c.536 A>T, considered a founder mutation, was identified in 10 patients (15.63%, 10/64), followed by BRCA1 c.2635 G>T (6.25%, 4/64) and BRCA2 c.2566 T>C (6.25%, 4/64).

Conclusion

The BRCA1 c.536 A>T could be considered to be a founder mutation in this ovarian cancer population. This recurrent BRCA1 mutation has rarely been observed in other ethnic groups. Our findings are expected to provide valuable data for clinical consultation and for designing individualized treatment for ovarian cancer.

Fecal microbial signatures of healthy Han individuals from three bio-geographical zones in Guangdong

Important forensic evidence traced from crime scenes, such as fecal materials, can help in the forensic investigation of criminal cases. Intestines are the largest microbial pool in the human body whose microbial community is considered to be the human "second fingerprint". The present study explored the potential for community characteristics of gut microbes in forensic medicine. Fecal microbiota profiles of healthy individuals from three representative Han populations (Guangzhou, Shantou and Meizhou) in Guangdong Province, China were evaluated using High-throughput sequencing of V3-V4 hypervariable regions of the 16SrRNA gene. Results of the present study showed that at the genus level, Shantou, Guangzhou, and Meizhou behaved as Enterotype1, Enterotype2, and Enterotype3, which were mainly composed of Bacteroides, Prevotella, and Blautia, respectively. Based on OTU abundance at the genus level, using the random forest prediction model, it was found that there might be potential for distinguishing individuals of Guangzhou, Meizhou, and Shantou according to their fecal microbial community. Moreover, the findings of the microbial community of fecal samples in the present study were significantly different from that of saliva samples reported in our previous study, and thus it is evident that the saliva and feces can be distinguished. In conclusion, this study reported the fecal microbial signature of three Han populations, which may provide basic data for the potential application in forensic practice, containing body fluid identification, and geographical inference.

Genetic polymorphisms of methylenetetrahydrofolate reductase C677T and risk of ischemic stroke in a southern Chinese Hakka population

Previous studies have shown that methylenetetrahydrofolate reductase (MTHFR) gene to be a genetic risk factor for the susceptibility to ischemic stroke. The aim of this case-control study was to investigate whether the polymorphisms of MTHFR C677T were associated with the susceptibility to ischemic stroke in a southern Chinese Hakka population. In this study, a total of 1967 ischemic stroke patients and 2565 controls of Chinese Hakka ethnicity were recruited. The MTHFR C677T polymorphisms were genotyped by polymerase chain reaction (PCR) amplification and microarray method. The risk of ischemic stroke was estimated by logistic regression analysis. The frequencies of CC, CT, and TT genotypes were 52.67% versus 55.63%, 40.31% versus 38.52%, and 7.02% versus 5.85% in patients with ischemic stroke versus controls, respectively. The frequency of T allele was significantly higher in ischemic stroke patients (27.17%) than in controls (25.11%) (P = .026, odds ratio [OR] 1.113, 95% confidence interval [CI] 1.013-1.223). The homozygous TT genotype in the ischemic stroke patients was associated with increased risk (P = .049, OR 1.132, 95% CI 1.001-1.281) when compared with the controls after adjustment for age and sex. The positive association was only found in dominant model without adjustment for age and sex (P = .047, OR 1.127, 95% CI 1.002-1.268). Also, the carrier status of the MTHFR T allele was identified as an independent risk factor for the development ischemic stroke even after the adjustment for conventional risk factors (P = 0.047, OR 1.109, 95% CI 0.964-1.225). Our results provide evidence that variants of MTHFR C677T gene may influence the risk of developing ischemic stroke in a southern Chinese Hakka population. Further studies are needed to confirm this association, which will promote the development of strategies for prevention and treatment of ischemic stroke in our study population.

Prevalence and genotype distribution of human papillomavirus infection among women in northeastern Guangdong Province of China

BACKGROUND

Human papillomavirus (HPV) DNA testing is an important method in cervical cancer screening. However, the studies on prevalence and genotype distribution of HPV among women in northeastern Guangdong Province of China are very limited.

METHODS

A total of 28,730 women attending the Department of Gynecology of Meizhou People's Hospital (Huangtang Hospital), Meizhou Hospital Affiliated to Sun Yat-sen University between January 1st, 2013 and June 1st, 2015 were enrolled in this study. HPV type-specific distribution was tested using flow-through hybridization and gene chip.

RESULTS

The overall prevalence of HPV infection was 19.81%, among which 79.09% were infected with high-risk HPV subtypes in the subjects. The 5 most predominant genotypes were HPV16, 52, 58, 18 and 81. Most HPV infections were observed in women aged 41-50 and women aged 30-59 accounted for a proportion of over 80%.

CONCLUSIONS

Our findings suggested a high burden of HPV infection among women in northeastern Guangdong Province of China. We identified the top 5 HPV genotypes as well as the age-specific distribution of HPV infections in this area.

Genetic Polymorphisms of the Mitochondrial Aldehyde Dehydrogenase ALDH2 Gene in a Large Ethnic Hakka Population in Southern China

Background

Human mitochondrial aldehyde dehydrogenase 2 (ALDH2) plays a critical role in the detoxification of the ethanol metabolite acetaldehyde. The ALDH2*2 (rs671) gene variant is mainly absent among Europeans but is prevalent in populations in East Asia. The aim of this study was to investigate ALDH2*2 mutant alleles and genotype frequencies in the Hakka population of China.

Material/Methods

Between January 2016 and June 2017, 7,966 unrelated individuals were recruited into the study from the Hakka ethnic population residing in the Meizhou area of Guangdong Province, China, who provided venous blood samples. Genotyping of ALDH2 genotypes were determined using a gene chip platform and confirmed by DNA sequencing.

Results

In the 7,966 individuals from the Hakka population of China in this study, the frequencies of the ALDH2 genotypes *1/*1, *1/*2 and *2/*2 were 52.03%, 39.67%, and 8.30%, respectively; 47.97% of the individuals were found to carry the ALDH2*2 genotype, which was associated with a deficiency in the aldehyde dehydrogenase (ALDH2) enzyme activity. The frequency of the ALDH2*2 allele was lower than that previously reported in the Japanese population but higher than that reported in other Oriental populations.

Conclusions

The findings of this study have provided new information on the ALDH2 gene polymorphisms in the Hakka ethnic population residing in the Meizhou area of Guangdong Province, China, including an understanding of the origin of the atypical ALDH2*2 allele. Also, the study findings may be relevant to the primary care of patients in China.

Molecular prenatal diagnosis of alpha and beta thalassemia in pregnant Hakka women in southern China

BACKGROUND

To date, there has been no systematic study of DNA-based prenatal diagnosis of thalassemia in pregnant Hakka women in southern China.

METHODS

A total of 279 pregnant Hakka women with confirmed cases of thalassemia who had been treated at the Meizhou People's Hospital in China's Guangdong Province from January 2014 to December 2016 were here enrolled. Genomic DNA was extracted from peripheral blood of couples and villus, amniotic fluid, or fetal cord blood. DNA-based diagnosis was performed on the tissues of fetuses whose parents had tested positive for α- and β-globin gene mutations were found using polymerase chain reaction (PCR) and flow-through hybridization technique. Follow-up visits were performed 6 months after the fetuses were born. Prenatal diagnosis was performed on 279 fetuses in at-risk pregnancies.

RESULTS

Here, 211 α-thalassemia fetuses were confirmed, including 41 (19.43%) that tested positive for Bart's hydrops syndrome and 15 (7.11%) for Hb H disease. There were 103 (48.81%) heterozygotes. β-thalassemia was confirmed in 68 fetuses, including 23 (33.82%) with severe thalassemia and 27 (39.71%) heterozygotes. Another 12 cases were confirmed with α+β-thalassemia, including three cases of severe β-thalassemia. DNA-based testing prenatal diagnosis of thalassemia was found to be highly reliable.

CONCLUSIONS

Our findings provide key information for clinical genetic counseling of prenatal diagnosis for major thalassemia in pregnant Hakka women in southern China.

Analysis of CYP2C19 Genetic Polymorphism in a Large Ethnic Hakka Population in Southern China

Background

Cytochrome P450 (CYP) 2C19 is an enzyme involved in the bioactivation of various important therapeutic drugs, from pro-drugs to an active inhibitor of platelet action. Variants in the CYP2C19 gene influence the pharmacokinetics and clinical response to antiplatelet drugs such as clopidogrel; however, there is no available data about the genetic variation of CYP2C19 in the Hakka population in China.

Material/Methods

A total of 6686 unrelated participants (ages 17–98 years) of self-reported Hakka ancestry admitted at an inpatient department in a hospital in southern China were successfully genotyped by the gene chip platform.

Results

The identified allele frequencies were CYP2C19*1 (64.33%), *2 (31.06%) and *3 (4.61%). The major prevalent genotype combinations were CYP2C19 *1/*1 (41.73%) and *1/*2 (39.65%). The distribution of CYP2C19 phenotypes was divided into extensive metabolizers (EM) (41.73%), intermediate metabolizers (IM) (45.21%), and poor metabolizers (PM) (13.06%). In the Hakka population, frequencies of the CYP2C19 *2 and *3 variants were observed to be close to those previously identified in Chinese and several other Asian populations.

Conclusions

Our study is the first to report on CYP2C19 polymorphisms in the Hakka population, and may help to optimize pharmacotherapy effectiveness by providing personalized medicine to this ethnic group in the near future.

A genetic contribution from the Far East into Ashkenazi Jews via the ancient Silk Road

Contemporary Jews retain a genetic imprint from their Near Eastern ancestry, but obtained substantial genetic components from their neighboring populations during their history. Whether they received any genetic contribution from the Far East remains unknown, but frequent communication with the Chinese has been observed since the Silk Road period. To address this issue, mitochondrial DNA (mtDNA) variation from 55,595 Eurasians are analyzed. The existence of some eastern Eurasian haplotypes in eastern Ashkenazi Jews supports an East Asian genetic contribution, likely from Chinese. Further evidence indicates that this connection can be attributed to a gene flow event that occurred less than 1.4 kilo-years ago (kya), which falls within the time frame of the Silk Road scenario and fits well with historical records and archaeological discoveries. This observed genetic contribution from Chinese to Ashkenazi Jews demonstrates that the historical exchange between Ashkenazim and the Far East was not confined to the cultural sphere but also extended to an exchange of genes.

Mitochondrial DNA haplogroup confers genetic susceptibility to nasopharyngeal carcinoma in Chaoshanese from Guangdong, China

Recent studies have shown association of mtDNA background with cancer development. We analyzed mitochondrial DNA (mtDNA) control region variation of 201 patients with nasopharyngeal carcinoma (NPC) and of 201 normal controls from Chaoshan Han Chinese to discern mtDNA haplogroup effect on the disease onset. Binary logistic regression analysis with adjustment for gender and age revealed that the haplogroup R9 (P = 0.011, OR = 1.91, 95% CI = 1.16-3.16), particularly its sub-haplogroup F1 (P = 0.015, OR = 2.43, 95% CI = 1.18-5.00), were associated significantly with increased NPC risk. These haplogroups were further confirmed to confer high NPC risk in males and/or individuals ≥ 40 years of age, but not in females or in subjects <40 years old. Our results indicated that mtDNA background confers genetic susceptibility to NPC in Chaoshan Han Chinese, and R9, particularly its sub-haplogroup F1, is a risk factor for NPC.

Mitochondrial DNA content contributes to climate adaptation using Chinese populations as a model

Maintaining a balance between ATP synthesis and heat generation is crucial for adapting to changes in climate. Variation in the mitochondrial DNA (mtDNA), which encodes 13 subunits of the respiratory chain complexes, may contribute to climate adaptation by regulating thermogenesis and the use of bioenergy. However, studies looking for a relationship between mtDNA haplogroups and climate have obtained mixed results, leaving unresolved the role of mtDNA in climate adaptation. Since mtDNA content can regulate human bioenergy processes and is known to influence many physiological traits and diseases, it is possible that mtDNA content contributes to climate adaptation in human populations. Here, we analyze the distribution of mtDNA content among 27 Chinese ethnic populations residing across China and find a significant association between mtDNA content and climate, with northern populations having significantly higher mtDNA content than southern populations. Functional studies have shown that high mtDNA content correlates with an increase in the expression of energy metabolism enzymes, which may accelerate thermogenesis. This suggests that the significantly higher mtDNA content observed in northern populations may confer a selective advantage in adapting to colder northern climates

Hemoglobinopathy: molecular epidemiological characteristics and health effects on Hakka people in the Meizhou region, southern China

Background

Hemoglobinopathies are the most common inherited diseases in southern China. However, there have been only a few epidemiological studies of hemoglobinopathies in Guangdong province.

Materials and Methods

Peripheral blood samples were collected from 15299 “healthy” unrelated subjects of dominantly ethnic Hakka in the Meizhou region, on which hemoglobin electrophoresis and routine blood tests were performed. Suspected cases with hemoglobin variants and hereditary persistence of fetal hemoglobin (HPFH) were further characterized by PCR, DNA sequencing, reverse dot blot (RDB) or multiplex ligation-dependent probe amplification (MLPA). In addition, 1743 samples were randomly selected from the 15299 subjects for thalassemia screening, and suspected thalassemia carriers were identified by PCR and RDB.

Results

The gene frequency of hemoglobin variants was 0.477% (73/15299). The five main subgroups of the ten hemoglobin variants were Hb E, Hb G-Chinese, Hb Q-Tahiland, Hb New York and Hb J-Bangkok. 277 cases (15.89%, 277/1743) of suspected thalassemia carriers with microcytosis (MCV<82 fl) were found by thalassemia screening, and were tested by a RDB gene chip to reveal a total of 196 mutant chromosomes: including 124 α-thalassemia mutant chromosomes and 72 β-thalassemia mutant chromosomes. These results give a heterozygote frequency of 11.24% for common α and β thalassemia in the Hakka population in the Meizhou region. 3 cases of HPFH/δβ-thalassemia were found, including 2 cases of Vietnamese HPFH (FPFH-7) and a rare Belgian ^Gγ(^Aγδβ)⁰–thalassemia identified in Chinese.

Conclusions

Our results provide a detailed prevalence and molecular characterization of hemoglobinopathies in Hakka people of the Meizhou region. The estimated numbers of pregnancies each year in the Meizhou region, in which the fetus would be at risk for β thalassemia major or intermedia, Bart’s hydrops fetalis, and Hb H disease, are 25 (95% CI, 15 to 38), 40 (95% CI, 26 to 57), and 15 (95% CI, 8 to 23), respectively.

Tracing the legacy of the early Hainan Islanders--a perspective from mitochondrial DNA

BACKGROUND

Hainan Island is located around the conjunction of East Asia and Southeast Asia, and during the Last Glacial Maximum (LGM) was connected with the mainland. This provided an opportunity for the colonization of Hainan Island by modern human in the Upper Pleistocene. Whether the ancient dispersal left any footprints in the contemporary gene pool of Hainan islanders is debatable.

RESULTS

We collected samples from 285 Li individuals and analyzed mitochondrial DNA (mtDNA) variations of hypervariable sequence I and II (HVS-I and II), as well as partial coding regions. By incorporating previously reported data, the phylogeny of Hainan islanders was reconstructed. We found that Hainan islanders showed a close relationship with the populations in mainland southern China, especially from Guangxi. Haplotype sharing analyses suggested that the recent gene flow from the mainland might play important roles in shaping the maternal pool of Hainan islanders. More importantly, haplogroups M12, M7e, and M7c1* might represent the genetic relics of the ancient population that populated this region; thus, 14 representative complete mtDNA genomes were further sequenced.

CONCLUSIONS

The detailed phylogeographic analyses of haplogroups M12, M7e, and M7c1* indicated that the early peopling of Hainan Island by modern human could be traced back to the early Holocene and/or even the late Upper Pleistocene, around 7-27 kya. These results correspond to both Y-chromosome and archaeological studies.