Lactase persistence/non-persistence variants, C/T_13910 and G/A_22018, as a diagnostic tool for lactose intolerance in IBS patients

BACKGROUND: Irritable bowel syndrome (IBS) is a symptom-based disorder characterized by abdominal pain related to altered bowel habit. We evaluated the predictive power of 2 genetic markers of hypolactasia, C/T_13910 and G/A_22018, in IBS patients with and without lactose intolerance in order to gain insight into the role of lactose intolerance in IBS. METHODS: Seventy five patients (59F/16M, mean age: 49.6+/-14.2 years) with an IBS diagnosis based on Rome II criteria and 272 healthy individuals, where 74 (58F/16M, 54.1+/-10.9 years) were matched-controls, were evaluated. IBS and healthy individuals were genotyped for the C/T_13910 and G/A_22018 polymorphisms nearby the lactase-phlorizin hydrolase gene. Hydrogen breath test (HBT) with gas chromatography was performed in IBS patients to assess for lactose intolerance. RESULTS: Of the 75 IBS patients, 28 (37%) were defined as lactose intolerants. The grade/severity of symptoms after an oral lactose load were positively correlated to the expiratory H2 excretion (P<0.001). Alleles and genotypes frequencies from C/T_13910 and G/A_22018 were not significantly different between IBS patients and control individuals (P>0.05;NS). Presence of the C and G allele were positively associated with a higher expiratory hydrogen excretion and more intense gastrointestinal symptoms (P<0.001). Considering these polymorphisms as a diagnostic test for lactose intolerance in IBS patients, presence of the CC and GG genotypes were estimated to have, a sensitivity of 100% and 96%, respectively; and a specificity of 83% and 79%, positive predictive value of 76% and 73%, and negative predictive value of 100% and 97%. CONCLUSIONS: In IBS patients, genotyping of C/T_13910 and G/A_22018 polymorphisms predicts gastrointestinal symptoms after lactose ingestion and are a diagnostic tool for lactose intolerance.     

High-resolution melting analysis using unlabeled probe and amplicon scanning simultaneously detects several lactase persistence variants

Lactase persistence and thereby tolerance to lactose is a common trait in people of Northern European descent. It is linked to the LCT -13910C>T variant located in intron 13 of the MCM6 gene 13.9 kb upstream of the lactase (LCT) gene. In people of African and Middle Eastern descent, lactase persistence can be associated with other variants nearby the -13910C>T variant, limiting the use of the -13910C>T-based SNP analysis, e.g. TaqMan assays for the diagnosis of lactose intolerance. Using high-resolution melting analysis, we identified five samples that were heterozygous for the -13915T>G variant among 78 patients genotyped as -13910C/C by a TaqMan assay. All samples originated from patients of probable Middle Eastern descent. In order to detect the -13910 and -13915 variants simultaneously, we developed a new high-resolution melting (HRM) analysis assay based on unlabeled probe genotyping and simultaneous amplicon scanning analysis. By using this assay we were able to distinguish the -13910 and -13915 genotypes clearly. Furthermore, we identified two rare variants, the -13907C>G and -13913T>C. With this method, based on an inexpensive unlabeled probe, it is possible to simultaneously detect the -13910C>T and -13915T>G variants in addition to rarer variants surrounding the -13910 site. This new method may contribute to improve the diagnostic performance of the genetic analysis for lactose intolerance.     

Simultaneous genotyping of the three lactose tolerance-linked polymorphisms LCT -13907C>G, LCT -13910C>T and LCT -13915T>G with Pyrosequencing technology.

BACKGROUND: We required a new genotyping method for the diagnosis of adult hypolactasia, which would allow the simultaneous genotyping of three known polymorphic loci linked to lactose tolerance (LCT -13907C>G, LCT -13910C>T and LCT -13915T>G) in a single PCR/pyrosequencing test run. METHOD: We utilized Pyrosequencing technology, a DNA-sequence-by-synthesis technique. RESULTS: The developed Pyrosequencing method allowed genotyping of the three loci LCT -13907C>G, LCT -13910C>T and LCT -13915T>G in a single PCR/pyrosequencing test run. A separate Pyrosequencing assay was developed for genotyping of the LCT -14010G>C mutation. The methods were evaluated in 116 clinical samples from patients of non-European descent, sent to the laboratory for diagnosis of adult hypolactasia. The "African" mutations LCT -13907C>G and LCT -13915T>G were found in subjects originating not only from Somalia, Ethiopia and Eritrea but also in Arabs and Iranians. Several compound heterozygotes LCT -13907CG/-13915TG were found among Ethiopian, Eritrean and Somalian subjects. No subject with the LCT -14010G>C mutation was found among the studied subjects. Advantages compared to the other genotyping methods are less staff hands-on time than, e.g., restriction fragment length polymorphism (RFLP) analyses, avoiding radioactivity as in the originally described isotope-minisequencing and in addition, Pyrosequencing is a direct DNA sequencing technique which gives unambiguous genotyping results as well as some redundant sequence information beyond the single nucleotide polymorphism (SNP) position, which serves as a valuable internal control obtained for each sample. CONCLUSIONS: Pyrosequencing is a robust genotyping modality suitable for clinical genotyping of patients not only of European, but also of African or Middle Eastern descent, who may harbor any combination of the three LCT mutations, LCT -13907C>G, LCT -13910C>T, LCT -13915T>G.     

Evaluation of a novel reverse-hybridization StripAssay for typing DNA variants useful in diagnosis of adult-type hypolactasia

BACKGROUND: Adult-type hypolactasia is a genetically determined inability to digest lactose after weaning. Two single-nucleotide polymorphisms (C-13910T, G-22018A) located upstream of the lactase gene (LCT) within the gene MCM6 are associated with the lactase persistence/non-persistence trait in patients of European descent. Therefore, the genotyping of these SNPs has been established as a diagnostic tool for adult-type hypolactasia. We have recently shown that several novel allelic variants located in close proximity to the C-13910T SNP interfere with the diagnostic accuracy of real-time PCR-based genotyping methods. METHODS: We describe here the validation of a comprehensive reverse-hybridization teststrip-based assay for the detection of common and novel LCT SNPs (C-13907G, C-13910T, T-13913C, G-13914A, T-13915G, and G-22018A). This assay is based on multiplex DNA amplification and ready-to-use membrane teststrips containing variant-specific oligonucleotide probes immobilized as an array of parallel lines. RESULTS: We evaluated the novel reverse-hybridization StripAssay on 125 DNA samples in comparison to LightCycler analysis and sequencing. The outcome of StripAssay genotyping was found to be completely concordant with that obtained by sequencing. CONCLUSIONS: The StripAssay represents an accurate and robust screening tool to identify multiple LCT/MCM6 variants in a rapid manner. It overcomes diagnostic pitfalls that were reported and allows the simultaneous genotyping of closely spaced LCT variant sites in a single-step diagnostic approach.     

Hydrogen breath testing versus LCT genotyping for the diagnosis of lactose intolerance: a matter of age?

BACKGROUND: Two single nucleotide polymorphisms (-13910 C/T and -22018 G/A) upstream of the lactase gene (LCT) have been found to be associated with lactose tolerance in Europeans. METHODS: In one hundred and twenty Austrian outpatients, who visited the physician's office for symptoms of irritable bowel syndrome (IBS), hydrogen breath testing (HBT) and LCT genotyping by polymerase chain reaction and reverse-hybridisation were performed in parallel. RESULTS: The coincidence between a genotype suggesting lactase non-persistence (lactose intolerance) and a positive HBT result was almost perfect (97.4% for LCT-13910 C/T and 100% for LCT-22018 G/A). Between a genotype indicating lactase persistence (lactose tolerance) and a negative HBT result the coincidence was lower (72% and 71.4%, respectively). Among heterozygotes, there was a statistically significant increase in the proportion of positive HBT results with age. Both SNPs were in accordance in 117/120 (97.5%) patients. CONCLUSION: Genetic analysis of LCT-13910 C/T and LCT-22018 G/A is a good indicator for the presence of lactose intolerance. Because age, as well as a number of secondary causes (e.g. celiac disease), can influence HBT results, it is useful to combine HBT and genetic analysis in the diagnostic assessment of IBS.     

High-resolution melting analysis using unlabeled probe and amplicon scanning simultaneously detects several lactase persistence variants

Abstract

Lactase persistence and thereby tolerance to lactose is a common trait in people of Northern European descent. It is linked to the LCT ?13910C>T variant located in intron 13 of the MCM6 gene 13.9 kb upstream of the lactase (LCT) gene. In people of African and Middle Eastern descent, lactase persistence can be associated with other variants nearby the ?13910C>T variant, limiting the use of the ?13910C>T-based SNP analysis, e.g. TaqMan assays for the diagnosis of lactose intolerance. Using high-resolution melting analysis, we identified five samples that were heterozygous for the ?13915T>G variant among 78 patients genotyped as ?13910C/C by a TaqMan assay. All samples originated from patients of probable Middle Eastern descent. In order to detect the ?13910 and ?13915 variants simultaneously, we developed a new high-resolution melting (HRM) analysis assay based on unlabeled probe genotyping and simultaneous amplicon scanning analysis. By using this assay we were able to distinguish the ?13910 and ?13915 genotypes clearly. Furthermore, we identified two rare variants, the ?13907C>G and ?13913T>C. With this method, based on an inexpensive unlabeled probe, it is possible to simultaneously detect the ?13910C>T and ?13915T>G variants in addition to rarer variants surrounding the ?13910 site. This new method may contribute to improve the diagnostic performance of the genetic analysis for lactose intolerance.     

Genetic testing for adult-type hypolactasia in Italian families

BACKGROUND: Adult-type hypolactasia is characterized by the inability to digest lactose during adulthood, due to lactase (LCT) deficiency. It is usually diagnosed by the measurement of breath hydrogen increase after a lactose load (breath hydrogen test, BHT). A substitution of C to T at position -13910 bp upstream the LCT gene (rs4988235), in a regulatory region, was found to be strongly associated with the lactase persistence phenotype in North-European populations. METHODS: We investigated the -13910 C/T polymorphism to determine LCT genotype distribution and to validate genetic testing for adult-type hypolactasia in a Southern European population. A total of 43 children referred for suspected lactose malabsorption were enrolled in the study, their parents and siblings (whole sample=112 individuals) also took the breath test, and all were enrolled for clinical monitoring and genotype determination. In addition, 125 unrelated blood donors from the same geographic area were genotyped for the calculation of allelic frequencies. The frequency of C/C genotypes was 70%. RESULTS: The correlation between the C/C genotype (which should correspond to lactose non-digesters) and positive BHT in unrelated family founders was significant (chi(2)=16.7, p<0.002). The genetic test compared to the BHT had a sensitivity of 95% and 91% and a specificity of 48% and 55% in adults and children, respectively. CONCLUSIONS: Low specificity might be due to intrinsic limitations of the standard BHT or to other possible mutations, although no sequence variation was found upon sequencing a 253 bp fragment of the LCT regulatory region in asymptomatic individuals.     

Molecular genetics of adult-type hypolactasia

Adult-type hypolactasia (lactase non-persistence; primary lactose malabsorption) is characterized by the down-regulation of the lactase enzyme activity in the intestinal wall after weaning. The down-regulation is genetically determined and a mutation has occurred that has made part of mankind tolerate milk (lactase persistence). A DNA-variant, single nucleotide polymorphism C/T-13910 located 13 910 base pairs (bp) upstream of the lactase gene (LCT) at chromosome 2q21-22 has been shown to associate with the lactase persistence/non-persistence trait both in family and case-control studies. The C/T-13910 variant is located in a non-coding region in the genome in intron 13 of the minichromosome maintenance type 6 gene (MCM6). Significant correlation between the C/T-13910-variant and lactase activity in the intestinal biopsy specimens has been demonstrated. Molecular epidemiological studies on the prevalence of the C/C-13910 genotype associated with low lactase activity are in agreement with the prevalence figures for adult type hypolactasia in>70 diverse ethnic groups studied. Recent functional studies have suggested that this variant has an enhancer effect over the lactase gene. Based on the biochemical, functional, genetic and molecular epidemiological studies of the C/T-13910 variant, genetic testing for adult type hypolactasia has been introduced into clinical practice in Finland. Identification of the genetic change has highlighted the role of non-coding variants in the regulation of common genes and created new tools to study the mechanism of lactase enzyme activation.     

Single nucleotide polymorphism C/T(-13910), located upstream of the lactase gene, associated with adult-type hypolactasia: validation for clinical practice

ObjectivesTo validate C/T_-13910 polymorphism associated with primary hypolactasia for clinical practice.Design and methodsLactose breath test and PCR-RFLP for the C/T_-13910 polymorphism were performed.ResultsTwenty-seven of 28 patients with genotype CC had positive breath tests; all twenty-two patients with genotypes CT or TT had negative breath tests. Agreement of tests was high (p < 0.0001; Kappa Index 0.96).ConclusionC/T_-13910 polymorphism detection may be a new tool for primary hypolactasia diagnosis.     

Adult-type hypolactasia is not a predisposing factor for the early functional and structural changes of atherosclerosis: the Cardiovascular Risk in Young Finns Study

Individuals suffering from ATH (adult-type hypolactasia), defined by the LCT (gene encoding lactase-phlorizin hydrolase) C/C(-13910) genotype (rs4988235), use less milk and dairy products and may have higher plasma HDL (high-density lipoprotein) and lower triacylglycerol (triglyceride) concentrations than their counterparts without ATH. To investigate the effects of ATH status on the early markers of atherosclerosis, we examined its association with CIMT (carotid intima-media thickness), CAC (carotid artery compliance) and brachial artery FMD (flow-mediated dilation) in a young population-based cohort of otherwise healthy individuals. As part of the Cardiovascular Risk in Young Finns Study, we performed CIMT, CAC and FMD analyses, LCT C/T(-13910) genotyping and risk factor determination in 2109 young subjects 24-39 years of age (45% males) at the time of the examination. The consumption of both milk and dairy products was lowest and the consumption of alcohol highest in subjects with the C/C(-13910) genotype (P<0.001 for all) in comparison with subjects without ATH (TT+CT). In multivariate analysis, no significant association between ATH status and CIMT, CAC or brachial artery FMD was found after adjustment for the use of alcohol, dairy products and all other major risk factors of coronary artery disease. In otherwise similar statistical analysis, the results remained non-significant when females and males were analysed in their own groups. In conclusion, the finding does not support the involvement of ATH in the pathogenesis of early atherosclerosis.     

Molecular genetics of adult‐type hypolactasia

Adult‐type hypolactasia (lactase non‐persistence; primary lactose malabsorption) is characterized by the down‐regulation of the lactase enzyme activity in the intestinal wall after weaning. The down‐regulation is genetically determined and a mutation has occurred that has made part of mankind tolerate milk (lactase persistence). A DNA‐variant, single nucleotide polymorphism C/T_?13910 located 13 910 base pairs (bp) upstream of the lactase gene (LCT) at chromosome 2q21‐22 has been shown to associate with the lactase persistence/non‐persistence trait both in family and case‐control studies. The C/T_?13910 variant is located in a non‐coding region in the genome in intron 13 of the minichromosome maintenance type 6 gene (MCM6). Significant correlation between the C/T_?13910‐variant and lactase activity in the intestinal biopsy specimens has been demonstrated. Molecular epidemiological studies on the prevalence of the C/C_?13910 genotype associated with low lactase activity are in agreement with the prevalence figures for adult type hypolactasia in>70 diverse ethnic groups studied. Recent functional studies have suggested that this variant has an enhancer effect over the lactase gene. Based on the biochemical, functional, genetic and molecular epidemiological studies of the C/T_?13910 variant, genetic testing for adult type hypolactasia has been introduced into clinical practice in Finland. Identification of the genetic change has highlighted the role of non‐coding variants in the regulation of common genes and created new tools to study the mechanism of lactase enzyme activation.     

Combination of real-time PCR and sequencing to detect multiple clinically relevant genetic variations in the lactase gene

Background: Lactase persistence is an autosomal dominant trait commonly distributed in Europe as well as some parts of east Africa and the Arabian Peninsula. Using real-time PCR to detect the ?13910C?>?T variant common in the European population is a reliable analysis although other variants in the probe-binding site may cause errors in analysis. The aim of this study was to determine the prevalence of the variants in a Danish cohort examined for lactose intolerance as well as to improve the real-time PCR analysis for detection of the different variants.

Methods: We genotyped 3395 routine samples using real-time PCR for the ?13910C?>?T-variant. All consecutive samples identified as ?13910CC were sequenced using Sanger Sequencing. Using the SDS software we examined various quality value settings to improve on the genetic analysis.

Results: Using real-time PCR resulted in 100% successful genotyping of the ?13910C?>?T variant. By using a quality value of 99% and sequencing the undetermined samples we improved the ability of the assay to identify variants other than ?13910C?>?T. This resulted in a reduction of the diagnostic error rate by a factor of 2.4 while increasing the expenses only 3%.

Conclusions: We conclude that using a quality value of 99% in the SDS software significantly improves the diagnostic efficiency of the real-time PCR assay for detecting variants associated to lactase persistence.     

Synergistic effect of high lactase activity genotype and galactose-1-phosphate uridyl transferase (GALT) mutations on idiopathic presenile cataract formation

ObjectivesTo evaluate the possible synergistic role of partial galactose metabolism defects, high lactase (LPH) genotype and lactose and galactose ingestion in presenile cataract formation.Design and methods51 patients with idiopathic presenile cataracts and 172 healthy cataract-free subjects were genotyped to determine their galactose-1-phosphate uridyl transferase (GALT) and LPH status. Whole milk, skimmed milk and yoghurt consumption was recorded in 19 cataract patients and 172 controls by questionnaire.ResultsGALT mutations and whole milk consumption increased the risk of cataract formation in high LPH genotype group, but not in lactose intolerant subjects. Logistic regression analysis showed the synergistic effect of GALT and LPH mutations on cataract formation.ConclusionsHigh lactase activity genotypes and mutations in galactose-1-phosphate uridyl transferase have a synergistic effect on presenile cataract formation.     

Effects of storage and viral load on hepatitis C viral genotyping.

Hepatitis C virus (HCV) genotyping is important for determining the treatment protocol for hepatitis C patients. Since amplified material from the Roche HCV Monitor kit is compatible with the Innogenetics INNO-LiPA HCV II kit (line probe assay), amplicons from the Monitor assay can be used to identify the HCV genotype. The Monitor package insert recommends using amplicons within a 7-day period (at 4 degrees C) following amplification. It was hypothesized that storage of amplicons for 4 weeks and longer (at -20 degrees C) would not affect the sensitivity of the genotyping assay. After denaturation, amplicons from two genotypes were stored for 7-386 days prior to performing the genotyping assay. Storage of amplicons did not hamper the ability to identify the genotype. Additionally, the sensitivity of the assay was evaluated by analyzing five genotypes with low viral loads. HCV genotypes were detected most consistently at viral levels of 10,000 copies/mL. In conclusion, the Innogenetics genotyping assay can use stored amplicons, thus reducing the cost of the assay by avoiding additional PCR reactions. Determining the sensitivity of this assay facilitates the efficient use of this test by incorporating a sensitivity cutoff of >or=10,000 copies/mL.     

Assessment of hypolactasia and site-specific intestinal permeability by differential sugar absorption of raffinose, lactose, sucrose and mannitol.

The sugar absorption test is a non-invasive test for investigating intestinal permeability by simultaneous measurement of four probe sugars. In this study, we evaluated the utility of raffinose, lactose, sucrose and mannitol as probe sugars and calculated their urinary recovery as a percentage of ingested dose (mol/mol) and the recovery ratios of raffinose/mannitol, lactose/ raffinose and sucrose/raffinose. The reference ranges for these ratios, established from 39 healthy volunteers, are 0.005-0.015, 0.13-0.63 and 0.09-0.47, respectively. This sugar absorption test was performed in three patient groups. i) In 109 patients with aspecific gastrointestinal symptoms of whom intestinal histology was studied by duodenal biopsies: the urinary raffinose/mannitol recovery ratio highly correlated with gradation of duodenal damage; the sensitivity and specificity of the raffinose/mannitol ratio for detection of intestinal damage were 93% and 91%, respectively, using a cut-off level of 0.020. ii) In 70 patients in whom intestinal lactase activity was investigated by the lactose tolerance test: the urinary lactose/raffinose recovery ratio provided high diagnostic accuracy for hypolactasia (sensitivity 81% and specificity 89% at a cut-off level of 0.70). In analogy with the lactose/raffinose ratio, we suppose that the sucrose/raffinose ratio can be used as a marker of hyposucrasia. iii) In 40 patients with localized small intestinal damage, Crohn's disease of the ileum (n = 21) and celiac disease with histologically proven duodenal damage (n = 19): the raffinose/mannitol recovery ratio was increased in 100% of patients with celiac disease and in 81% of patients with Crohn's disease; increased lactose/raffinose recovery ratio (hypolactasia) and increased sucrose/raffinose (hyposucrasia) were present in 89% and 95% of celiac patients and 19% and 0% of Crohn's disease patients, respectively. The combination of the raffinose/mannitol ratio and sucrose/raffinose ratio appears to be an indication of the distribution of intestinal damage.     

Association of cytochrome P450 2E1 genetic polymorphisms with squamous cell carcinoma of the oesophagus.

Squamous cell carcinoma of the oesophagus is one of the most common cancers among black males in South Africa. Genetic polymorphism in the cytochrome P450 2E1 (CYP2E1) gene, coding for one of the main enzymes involved in the bioactivation of tobacco- and alcohol-related substances, was investigated for its role in the development of oesophageal cancer. Three single nucleotide polymorphisms -1053C--> T, -1293G--> A (both give rise to CYP2E1*5 ) and 7632T--> A ( CYP2E1*6 ) in the 5'-untranslated region of CYP2E1 were investigated in 189 patients and 198 control individuals in South Africa. The mutant variants occurred between patients and controls at frequencies of 1% and 2% (-1053C--> T), 1% and 3% (-1293G--> A) and 18% and 7% (7632T--> A), respectively. In comparing patients with controls, the heterozygous CYP2E1*6 genotype was associated with increased risk of the development of squamous cell carcinoma of the oesophagus (odds ratio, 5.90; p < 0.001) after adjusting for age, sex, smoking and alcohol consumption. In contrast, we did not find a significant association between CYP2E1*5 and oesophageal cancer. Six novel mutations, -1371G--> A, -1359C--> G, -1342C--> G, -1261T--> del, -1189T--> C and -1103C--> G, were identified by DNA sequence analysis of the CYP2E1 promoter region. In summary, our case-control study of oesophageal cancer revealed an elevated risk associated with the CYP2E1*6 allele in South Africans.     

Effect of polymorphisms of endothelial nitric oxide synthase on ischemic stroke: a case-control study in a Chinese population

BACKGROUND: Nitric oxide (NO) synthesized by endothelial nitric oxide synthase (eNOS) plays a key role in vascular regulation and atherosclerosis, therefore, eNOS may be a candidate gene for ischemic stroke (IS). However, it is still controversial whether eNOS polymorphisms are a risk factor for IS. METHODS: Three polymorphisms of the eNOS gene (-922A/G, -786T/C, 894G/T) were determined by using TaqMan SNP genotyping assay in 309 Chinese patients with IS and 309 Chinese controls. RESULTS: The frequency of eNOS -922 G allele was significantly higher in the patients than the controls (12.14% vs 8.09%, P=0.018). The distribution of eNOS genotypes differed insignificantly between the 2 groups. The frequency of the eNOS -786 CC genotype was higher in the patients than the controls (OR=3.819, P=0.029). With respect to -922A/G, the AG+GG genotype increased the risk for IS (OR=1.523, P=0.047). After adjustment for confounding factors, the odds ratios of -786 CC and -922 variant genotype (AG+GG) for IS were 4.580 and 1.656, respectively. However, haplotype analysis revealed the frequencies of Hap4 (GCG) and Hap7 (GCT) were significantly higher in the patients than the controls (P=0.035, 0.042). CONCLUSIONS: eNOS -922A/G and -786T/C may affect the susceptibility to IS and certain haplotypes of the eNOS gene may be associated with a higher susceptibility to IS.     

INNO-LiPA乙型肝炎病毒基因分型方法的评价

目的　评价INNO LiPA乙型肝炎病毒基因分型的方法 ,并探讨了基因型与临床疾病的关系。方法　随机选取 113例慢性HBV感染者外周血采用INNO LiPA和S基因序列分析两种方法测定HBV基因型。结果　 1 INNO LiPA基因分型法与S基因序列分析法测定的基因型结果比较 ,符合率 82 3% (93/ 113) ,误判率 3 5 % (4/ 113) ,B/C型混合感染检出率 5 3% (6 / 113)。 2 LC组和HCC组C基因型比率高于AsC组 ,差异有显著性 (分别为 92 9%比 5 2 8% ,X2 =7 0 3,P <0 0 1和 88 9%比 5 2 8% ,X2 =3 91,P <0 0 5 ) ;LC组C基因型比率高于CHB组 ,差异有显著性 (92 9%比 6 1 1% ,X2 =5 12 ,P <0 0 5 )。结论　 1 INNO LiPA法是一种较灵敏的快速检测HBV基因型的实验方法 ,尤其检测混合基因型感染灵敏度高。 2 C基因型HBV感染与较重肝病有关。