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PubMed1997

HCV-RNA levels play an important role independently of genotype in predicting response to interferon therapy.

OBJECTIVE: To evaluate the relationship between hepatitis C virus (HCV)-RNA levels and genotypes in order to establish their potentially predictive role in interferon (IFN) response. DESIGN: To detect HCV genotype at baseline and HCV viraemia levels before and during IFN treatment in three groups of patients with different IFN response. METHODS: Our study included 85 patients with biopsy-proven chronic hepatitis C who underwent IFN therapy at standard schedule (3 MU thrice weekly for 6 months). On the basis of IFN response they were subdivided into three groups as follows: non responders (NR: 27 cases) when alanine aminotransferase (ALT) values (normal value: 0-40 IU) at the end of treatment were abnormal (101.7 +/- 10.4); responders relapsing (RR: 29 cases) when normal ALT values at the end of therapy (28.14 +/- 1.7) increased during follow-up; sustained (long-term) responders (LTR: 29 cases) when ALT values remained normal for at least 12 months of follow-up (ALT values at the end of therapy: 21.8 +/- 1.4). ALT activity was monitored monthly during therapy and each month during 12 months of follow-up. HCV genotype was evaluated before starting treatment whereas HCV-RNA viraemia was checked at baseline and at the 1st and 6th months of therapy. RESULTS: The baseline viral load was higher in the NR group than in the RR and LTR groups independently of genotype; HCV-RNA levels progressively decreased during therapy independently of response but the levels remained significantly higher in the NR group. Genotype 1b was prevalent in the NR group. However, levels of viraemia in genotype 1b LTR patients are significantly lower than in genotype 1b NR patients. CONCLUSION: These results suggest that among viral-related parameters viraemia alone seems to play an important role in predicting response to IFN independently of genotype.

Adult↗
PubMed2001

Homozygous and heterozygous CCR5-Delta32 genotypes are associated with resistance to HIV infection.

OBJECTIVE: To investigate evidence for resistance to HIV-1 infection associated with the heterozygous genotype CCR5-+/Delta32 and with the homozygous genotype CCR5-Delta32/Delta32, which results in a nonfunctional CCR5 receptor. DESIGN: Cohort study of initially HIV-seronegative high-risk individuals from eight different cities. Enrollment data were analyzed to investigate the association of demographic factors and risk behaviors with CCR5 genotypes on the assumption that increased genotype prevalence among persons with histories of longer or more intensive exposure to HIV would indicate HIV resistance associated with that genotype. Longitudinal data were analyzed to investigate the association of HIV seroincidence with CCR5 genotypes. The cohort of 2996 individuals included 1892 men who have sex with men (MSM), 474 male injection drug users (IDUs), 347 women at heterosexual risk, and 283 female IDUs. MEASUREMENTS: CCR5 genotype, HIV serostatus, demographic factors, and risk behaviors during the 6 months before enrollment, followed by measurement of HIV seroincidence during the subsequent 18 months (for men) and 24 months (for women). RESULTS: Forty (1.3%) subjects were homozygous CCR5-Delta32/Delta32 and 387 (12.9%) were heterozygous CCR5-+/Delta32. All but 1 CCR5-Delta32/Delta32 individuals and 51 CCR5-+/Delta32 individuals were Caucasian. Among 1531 Caucasian MSM, CCR5-+/Delta32 individuals were present more frequently (22.3%) among those reporting unprotected receptive anal intercourse than among those not reporting this risk (15.9%) (p =.002), suggesting a selective advantage of the heterozygous genotype. CCR5-+/Delta32 individuals also had a significantly reduced relative risk of HIV seroconversion adjusted for unprotected receptive anal intercourse compared with CCR5-/+ individuals (relative risk = 0.30, 95% confidence interval [CI]: 0.08-0.97). CCR5-Delta32/Delta32 prevalence among Caucasian MSM was significantly associated with age among subjects recruited from high HIV seroprevalence cities (New York City and San Francisco) (odds ratio [OR] for each decade increase in age = 2.57, CI: 1.56-4.21) but not among those recruited from lower HIV prevalence sites (Boston, Chicago, Philadelphia, Seattle, and Providence/Pawtucket, Rhode Island) (OR = 1.20, CI: 0.75-1.89). CONCLUSIONS: Cross-sectional and longitudinal analyses indicated that among high-risk HIV seronegative MSM, CCR5-+/Delta32 and CCR5-Delta32/Delta32 are associated with protection against HIV infection. These findings imply that strategies aimed at reducing susceptibility to HIV infection by blocking CCR5 receptor sites need not seek blockage of all receptor sites to achieve an imperfect but substantial degree of protection.

Adolescent↗
PubMed2003

ADH genotype does not modify the effects of alcohol on high-density lipoprotein.

BACKGROUND: Alcohol consumption has beneficial effects on mortality which are mainly due to reduction in cardiovascular disease. These are believed to be due, at least in part, to the increase in plasma high-density lipoprotein (HDL) which is associated with alcohol consumption. It has been proposed that ADH3 genotype modifies the relationships between alcohol intake and cardiovascular disease by altering the HDL response to alcohol. The aim of this paper was to test for effects of ADH2 and ADH3 genotypes on the response of HDL components to habitual alcohol consumption. METHODS: Adult male and female subjects were genotyped for ADH2 and ADH3; and plasma HDL cholesterol, apolipoprotein A-I, and apolipoprotein A-II were measured. Nine hundred one subjects had both ADH2 and ADH3 genotypes and HDL cholesterol results, while 753 had both genotypes and all three lipid results. The effect of alcohol intake on the three measured HDL components, and a factor score derived from them, was estimated for each of the ADH2 and ADH3 genotype groups. RESULTS: All the measured components of HDL increased with increasing alcohol consumption over the range of intakes studied, 0-4 drinks per day. There were no significant interactions between alcohol consumption and ADH2 or ADH3 genotypes. CONCLUSIONS: The concept that alcohol dehydrogenase genotype and alcohol metabolic rate modify the effects of alcohol on plasma HDL concentration is not supported by our results.

Adult↗
PubMed2004

Angiotensin converting enzyme genotype and chronic allograft nephropathy in protocol biopsies.

Genotype DD of the angiotensin-converting enzyme (ACE) is not associated with an increased incidence of native renal diseases, although it could modulate progression to renal failure in patients who already display chronic lesions. Because its role in renal allograft degeneration is not well characterized, whether ACE genotype was associated with the prevalence of chronic allograft nephropathy (CAN) was studied, in a group of protocol biopsies from 180 patients, or with the incidence of CAN in 152 patients with at least two sequential biopsies. As a control group, ACE genotype was also studied in 41 donors and 72 healthy subjects. For analyzing the influence of ACE genotype in graft survival, patients were grouped into six categories (II-normal biopsy, ID-normal, DD-normal, II-CAN, ID-CAN and DD-CAN). Finally, relative renal ACE mRNA levels were measured in 67 cases by real-time PCR using the delta threshold cycle method. ACE-DD genotype was more frequent in patients who received a transplant than in control subjects (43.3% versus 30.1%, P = 0.026), but prevalence (DD = 42.7% versus non-DD = 42.2%) or incidence (DD = 24.6% versus non-DD = 29.9%) of CAN was not different regarding recipient ACE genotype. Furthermore, patients with the ACE-DD genotype and CAN had the poorest graft survival (II-normal = 100%, ID-normal = 91%, DD-normal = 84%, II-CAN = 100%, ID-CAN = 66%, and DD-CAN = 36%; P = 0.034) and higher ACE mRNA levels than non-DD and CAN (DD = -3.36 +/- 2.35 versus non-DD = -5.65 +/- 1.72-fold in ACE copies; P = 0.012). It is concluded that ACE-DD genotype is not associated with an increased prevalence or incidence of CAN but is actually associated with higher ACE mRNA levels and poorer graft survival in patients who already display CAN.

Adult↗
PubMed2006

Recall of disclosed apolipoprotein E genotype and lifetime risk estimate for Alzheimer's disease: the REVEAL Study.

PURPOSE: To determine whether individuals recall their apolipoprotein E genotype and numeric lifetime risk estimates after undergoing a risk assessment for Alzheimer's disease. METHODS: One-hundred and four participants underwent Alzheimer's disease risk assessment that included disclosure of apolipoprotein E genotype and a numeric lifetime risk estimate. RESULTS: At six weeks and one year post-disclosure, 59% and 48% of participants, respectively, recalled their lifetime risk estimate, and 69% and 63% recalled their apolipoprotein E genotype. Participants were more likely to remember their genotype than numeric lifetime risk estimate at one year (P < 0.05). Apolipoprotein E epsilon4-positive participants had better recall of their genotype at both time points (P < 0.05). Participants were more likely to recall whether they carried the "risk-enhancing form of apolipoprotein E" than their specific genotype (P < 0.05). CONCLUSIONS: These data suggest that apolipoprotein E genotype, especially the presence of an epsilon4 allele, is more memorable than a numeric risk estimate for Alzheimer's disease. Participants recalled genotype information in a more simplified, binary form. Health professionals testing for complex disorders such as Alzheimer's disease must find an appropriate balance between communicating risk in an understandable format and addressing the probabilistic nature of the information.

Adult↗
PubMed2006

Genotype combinations of plasminogen activator inhibitor-1 and angiotensin-converting enzyme genes and risk for early onset of coronary heart disease.

BACKGROUND: Both angiotensin-converting enzyme genotype and plasminogen activator inhibitor type 1 genotype have an effect on fibrinolytic components and hence, may increase risk or advance occurrence of coronary heart disease. We examined the association of the angiotensin-converting enzyme and the plasminogen activator inhibitor type 1 genotypes, and their combinations, with early onset of coronary heart disease in a cohort of 907 patients with coronary heart disease. DESIGN AND METHODS: All patients with a coronary heart disease (International Classification of Diseases, 9th Rev. pos. 410-414), aged 30-70 years and participating in an inpatient rehabilitation program between January 1999 and May 2000 in two clinical centres in Germany were enrolled. The plasminogen activator inhibitor type 1 and the angiotensin-converting enzyme genotypes were determined by polymerase chain reaction, and the distribution was compared between patients with early (< or =55 years) and late (>55 years) onset of coronary heart disease. A multivariate analysis was employed to adjust for potentially confounding factors. RESULTS: Of the 907 included patients, 408 (45.0%) developed coronary heart disease before the age of 55 years. For the 4G/4G genotype of plasminogen activator inhibitor type 1 the odds ratio for early onset of coronary heart disease was 1.68 [95% confidence interval (CI) 1.01-2.57] and for the D/D genotype of angiotensin-converting enzyme the odds ratio was 1.22 (95% CI 0.84-1.76) after adjustment for covariates. In multivariate analysis an odds ratio of 3.10 (95% CI 1.51-6.36) was found for the association between the combined homozygosity for both polymorphisms (plasminogen activator inhibitor type 1 genotype 4G/4G and angiotensin-converting enzyme genotype D/D) and onset of coronary heart disease before the age of 55 years after controlling for sex, age, smoking, diabetes, hypertension, hyperlipidemia and school education. CONCLUSION: The co-existence of the 4G/5G polymorphism of the plasminogen activator inhibitor type 1 gene and the I/D polymorphism of the angiotensin-converting enzyme gene increases the risk for early onset of coronary heart disease in this population.

Adult↗
PubMed2007

Absence of an association between Mycobacterium tuberculosis genotype and clinical features in children with tuberculous meningitis.

OBJECTIVES: Animal studies point to increased virulence of certain mycobacterial strains, notably those of the Beijing genotype. There are limited data on mycobacterial genotypic diversity in children with tuberculous meningitis (TBM). We investigated mycobacterial genotypic diversity in children with TBM and analyzed the relationship among genotype, clinical presentation and outcome. PATIENTS AND METHODS: Data were extracted from an ongoing prospective study on children with confirmed TBM from 1992 through 2003 at a referral hospital in the Western Cape Province, South Africa. Mycobacterial isolates were genotyped by standardized restriction fragment length polymorphism methodology. Clinical data at diagnosis, inflammatory progression during the first month of antituberculosis therapy and neurologic outcomes after 6 months of therapy were analyzed according to the principal genetic group of the strain and the presence of the Beijing strain, respectively. RESULTS: Fifty-nine children were included (median age at diagnosis, 23 months); 37 presented with stage II and 22 with stage III presented with TBM. At completion of antituberculosis therapy, 6 children were neurologically normal, 22 were moderately neurologically impaired, 23 were severely neurologically impaired and 6 children died; detailed outcomes were not available in 2 children. All 3 principal genetic groups were represented (group 1, 27.1%; group 2, 59.3%; group 3, 13.6%); the most prevalent strains were of the Beijing genotype (family 29; 25.4%), followed by family 28 (10.2%) and family 11 (8.5%). Predictors of poor neurologic outcome included advanced disease at diagnosis and male gender. There was no association between the principal genetic group of the strain or the presence of the Beijing genotype, and clinical presentation or outcome. CONCLUSIONS: We found no association between Mycobacterium tuberculosis genotypes and clinical presentation or outcome.

Adolescent↗
PubMed1994

The entire nucleotide sequence and classification of a hepatitis C virus isolate of a novel genotype from an Indonesian patient with chronic liver disease.

Three hepatitis C virus (HCV) isolates were obtained from patients with chronic liver diseases in Indonesia which were not classifiable into any of the genotypes I/1a, II/1b, III/2a, IV/2b or V/3a reported previously. The entire nucleotide sequence was determined for one HCV isolate (HC-G9); the remaining two isolates were of the same genotype based on a > 95% similarity within their partial sequences spanning 2927 nucleotides (nt). The HC-G9 genome consisted of 9440 nt including the 5' untranslated region of 341 nt, an open reading frame of 9033 nt coding for a polyprotein of 3011 amino acids and the 3' untranslated region of 66 nt (U stretch of 17 to 47 nt at the extreme 3' terminus excluded). It differed by 20 to 33% in nucleotide sequence from any of 14 HCV genomes of genotypes I/1a to IV/2b whose full-length sequences are known. By the unweighted pair-group method with arithmetic mean, HC-G9 was on a major branch (group 1) of the phylogenetic tree of HCV to which genotypes I/1a and II/1b belong. It is proposed, therefore, that the novel genotype for HC-G9 should be called 1c. A method was developed to identify genotype 1c by PCR with a primer deduced from the core gene that was specific to it. Since genotype 1c was detected in seven (15%) of 48 HCV RNA samples from Indonesian patients with chronic liver disease, but not in any of 1097 from other districts of the world, it appears to have evolved and remained in Indonesia. In addition to its epidemiological importance, the association of genotype 1c HCV with the severity of liver disease and its response to interferons deserve to be evaluated.

Amino Acid Sequence↗
PubMed1999

Immunogenicity of variable regions of hepatitis C virus proteins: selection and modification of peptide epitopes to assess hepatitis C virus genotypes by ELISA.

The immunogenicity of variable regions of hepatitis C virus (HCV) proteins was studied by ELISA by using 543 synthetic peptides from 120 variable regions and 90 sera from HCV-infected patients. Some regions from certain genotypes were less immunogenic, or even non-immunogenic, compared with their equivalents in other genotypes. However, the mean recognition of all peptides from genotypes 1a, 1b and 3 by sera infected with genotypes 1a, 1b and 3, respectively, showed no significant differences, suggesting a similar overall immunogenicity of variable regions from these genotypes. Proteins NS4a, NS4b and NS5a were found to be the most immunogenic. Recognition of individual peptides by the sera of infected patients showed that the humoral response against HCV is patient-dependent. The work shows that 15-mer peptides may encompass several B-cell epitopes. These epitopes may lie in slightly different positions in different genotypes. Thirty-one percent of the 543 peptides were recognized by some of the 35 healthy donors. This may be a reflection of the large number of antigens to which they had been exposed, but it may also reflect a strategy of HCV to respond to immune pressure. After selection and modification, a set of 40 peptides was used to assess genotypes 1a, 1b, 1, 2 and 3 in the sera of HCV-infected patients, with sensitivities of 34.1, 48.5, 68.8, 58.3 and 48.9% and specificities of 100, 99.1, 97.1, 99.5 and 99%, respectively. The overall sensitivity and specificity for the assessment of genotypes 1, 2 and 3 were 64 and 98%, respectively.

Amino Acid Sequence↗
PubMed2000

A new genotype of hepatitis B virus: complete genome and phylogenetic relatedness.

The hepatitis B virus (HBV) genotype was determined in a total of 121 plasma samples collected in France and the US from patients chronically infected with HBV. HBV genotype A was predominant in this collection, appearing in 66 samples (54%), while genotypes B, C, D, E and F occurred in 4 (3%), 14 (12%), 23 (19%), 1 (1%) and 0 (0%) of samples, respectively. However, the genotype of a total of 13 (11%) samples (2 from France, 11 from the US) could not be determined with the methodology used. Sequence analysis, and subsequent phylogenetic analysis of the complete genome and the individual open reading frames, showed that the virus isolate from these samples was 3248 bp long and, phylogenetically, did not cluster with any of the known genotypes. This strain was provisionally called HBV genotype G. Virus isolates that were obtained from geographically separated regions like France and the US were closely related to each other. All virus strains analysed contained some characteristic differences when compared to genotype A: a translational stop codon at aa 2 and 28 of the preCore region; a 36 nt (12 aa) insert in the amino-terminal part of the Core antigen (HBcAg); a 2 aa deletion in the carboxy-terminal part of HBcAg; and a 1 aa deletion in the preS1 open reading frame. The deduced amino acid sequence of HBsAg suggests that this newly discovered genotype G strain belongs to serological group adw2.

Amino Acid Sequence↗
PubMed2002

Antigenic relationships between six genotypes of the small hydrophobic protein gene of mumps virus.

Six different genotypes of mumps virus, A, C, D, G, H and I, genotyped on the basis of the small hydrophobic protein gene sequence, were subjected to antigenic comparison. Monoclonal antibodies directed against the haemagglutinin-neuraminidase protein of the SBL-1 strain of genotype A were used in immunofluorescence tests with different mumps virus strains. In addition, the six virus genotypes were compared by cross-neutralization tests with human post-vaccination sera after vaccination with the Jeryl Lynn (JL) strain of mumps virus and with rabbit hyperimmune sera directed against the A or D genotypes of mumps virus. Genotypes C, D, G, H and I could not be antigenically separated. In contrast, three different virus strains of genotype A, SBL-1, JL and Kilham, were distinct and were found to represent three different serotypes within the A genotype of mumps virus. Vaccination of Swedish children with the JL strain of mumps virus resulted in clearly lower neutralization titres against the SBL-1 strain, which is endemic in Sweden, compared to the homologous vaccine titres.

Amino Acid Sequence↗
PubMed2005

A new intertype recombinant between genotypes C and D of hepatitis B virus identified in China.

Hepatitis B virus (HBV) genotypes have a characteristic geographical distribution. More than 90% of chronic HBV patients in China are infected with genotypes B or C. Here, eight HBV isolates that were initially classified as genotype D by PCR-restriction fragment length polymorphism analysis were analysed in detail. The complete HBV genome was sequenced and compared with 32 sequences retrieved from GenBank, representing HBV genotypes A-G. Phylogenetic analysis of the S gene (nt 10-800) classified all eight isolates as genotype D. However, phylogenetic analyses of nt 800-10 and the open reading frames (ORFs) of the precore/core and X genes classified all eight isolates as genotype C. This discordance between phylogenetic trees reconstructed on different ORFs suggested that intertype recombination has occurred in all eight isolates. By using the simplot program, the site of recombination with genotype D was located in the preS2/S region, spanning nt 10-799 in seven of eight isolates and nt 10-1499 in the other isolate. These results demonstrate that intertype recombination should be considered as a type of variation that increases the genetic diversity of HBV. Hybrids of different HBV genotypes might exhibit specific virological properties and their significance in the diagnosis and management of chronic hepatitis B deserves further investigation.

China↗
PubMed2005

Differential capacity for high-affinity manganese uptake contributes to differences between barley genotypes in tolerance to low manganese availability.

There is considerable variability among barley (Hordeum vulgare) genotypes in their ability to grow in soils containing a low level of plant available manganese (Mn). The physiological basis for the tolerance to low Mn availability is unknown. In this work, Mn2+ influx and compartmentation in roots of the Mn-efficient genotype Vanessa and the Mn-inefficient genotype Antonia were investigated. Two separate Mn transport systems, mediating high-affinity Mn2+ influx at concentrations up to 130 nm and low-affinity Mn2+ influx at higher concentrations, were identified in both genotypes. The two genotypes differed only in high-affinity kinetics with the Mn-efficient genotype Vanessa having almost 4 times higher V(max) than the inefficient Antonia, but similar K(m) values. Online inductively coupled plasma-mass spectrometry measurements verified that the observed differences in high-affinity influx resulted in a higher Mn net uptake of Vanessa compared to Antonia. Further evidence for the importance of the differences in high-affinity uptake kinetics for Mn acquisition was obtained in a hydroponic system with mixed cultivation of the two genotypes at a continuously low Mn concentration (10-50 nm) similar to that occurring in soil solution. Under these conditions, Vanessa had a competitive advantage and contained 55% to 75% more Mn in the shoots than did Antonia. Subcellular compartmentation analysis of roots based on 54Mn2+ efflux established that up to 93% and 83% of all Mn was present in the vacuole in Vanessa and Antonia, respectively. It is concluded that differential capacity for high-affinity Mn influx contributes to differences between barley genotypes in Mn efficiency.

Biological Transport↗
PubMed2001

Adaptive maintenance of genetic polymorphism in an intertidal barnacle: habitat- and life-stage-specific survivorship of Mpi genotypes.

In the northern acorn barnacle, Semibalanus balanoides, genotype frequencies of three genetic markers were tracked over time in four types of intertidal habitats. These habitats were selected to represent natural variation in several environmental parameters, specifically the degree of physical stress experienced by barnacles. Frequencies for one allozyme locus (Gpi) and a presumably neutral mtDNA marker were homogeneous among habitats in each temporal sample. Similarly, no temporal stratification in genotype frequencies was evident across the five sampling intervals: from planktonic larvae sampled in March to juveniles collected at the end of June. In contrast to the Gpi and mtDNA loci, Mpi genotypes significantly changed in frequency in two habitats in the high intertidal zone. On exposed substrate, the Mpi-FF homozygote increased in frequency, whereas the alternative homozygote, Mpi-SS, significantly decreased in frequency. Barnacles that were protected from environmental stress at high intertidal heights by the Ascophyllum nodosum algal canopy demonstrated the opposite pattern. In both habitats, the change in frequency of the heterozygote was intermediate to that of the homozygous genotypes. Furthermore, these patterns of genotype-by-environment association reflected a pulse of genotype-specific mortality that occurred over a two-week interval subsequent to metamorphosis from the larval to the adult form. These data indicate that each Mpi homozygote is the highest fitness genotype in some portion of the intertidal environment. Using the Levene (1953) model to evaluate the spatial variation in genotypic fitness, the stable maintenance of the Mpi polymorphism is predicted under certain subsets of conditions. Environmental heterogeneity in the intertidal zone translates to spatial variation in selection pressures, which may result in the active maintenance of the Mpi polymorphism in this species.

Adaptation, Biological↗
PubMed2001

Different susceptibility of each L-myc genotype to esophageal cancer risk factors.

To understand the relationship between the L-myc genotypes and esophageal cancer risk, a polymerase chain reaction-based restriction fragment length polymorphism analysis was performed on 91 Japanese patients with esophageal cancer and 241 non-cancer outpatients. No significant difference in the distribution of genotypes was observed between patients and controls; 18.7% LL genotype, 56.0% LS and 25.3% SS among patients, and 24.5%, 55.6% and 19.9%, respectively, among controls. Frequency of the s-allele in patients (0.533) was slightly higher than in controls (0.477), but the difference was not statistically significant. However, the odds ratios (ORs) for smoking or heavy drinking were markedly higher in SS and LS genotypes than in LL genotype; age-sex-adjusted ORs for smoking was 7.57 in the SS genotype, 6.40 in the LS genotype and 1.77 in the LL genotype. Age-sex-adjusted ORs for heavy drinking were 19.78, 18.20 and 7.40, respectively. The age-sex-adjusted ORs for both factors combined were 12.77, 18.45 and 1.44, respectively. These results suggested that the L-myc polymorphism might modify the effects of lifestyle factors on esophageal cancer risk.

Aged↗
PubMed2006

Genotypic effects of calpain 1 and calpastatin on the tenderness of cooked M. longissimus dorsi steaks from Jersey x Limousin, Angus and Hereford-cross cattle.

Single nucleotide polymorphisms (SNPs) in the calpain 1 (CAPN1) and calpastatin (CAST) genes were studied to determine their effects on meat tenderness in Bos taurus cattle. Strip loins (M. longissimus dorsi) were removed from cattle in four resource populations after slaughter (n = 1042), aged under controlled conditions until fixed times after rigor mortis, cooked and measured using a tenderometer. Animals were genotyped for the CAPN1 SNP c.947C>G (p.Ala316Gly; AF252504) and for the CAST SNP c.2959A>G (AF159246). Frequencies of CAPN1 C alleles ranged from 23% to 68%, and CAST A alleles from 84% to 99.5%. From all data combined, the CAPN1 CC genotype (compared with the GG genotype) was associated with a 20.1 +/- 1.7% reduced average shear force at intermediate stages of ageing (P < 0.001) and with a 9.5 +/- 1.3% reduction near ultimate tenderness (P < 0.001). The heterozygote was intermediate. For CAST, corresponding values for AA compared with AG genotypes were reductions of 8.6 +/- 2.0% and 5.1 +/- 1.6% respectively (both P < 0.001), but there were too few GG genotypes for comparison. There were small interactions between the CAPN1 and CAST genotypes. For the CAPN1 and CAST genotypes combined, the maximal genotype effect in average shear force was 25.7 +/- 5.5% (P < 0.001) at intermediate stages and 15.2 +/- 4.8% near ultimate tenderness (P < 0.01).

Alleles↗
PubMed1995

Relation between changes in blood pressure and serum ACE activity after a single dose of enalapril and ACE genotype in healthy subjects.

1. The effects of a single oral dose of enalapril 10 mg on serum ACE activity and blood pressure in relation to the ACE genotype were studied in 27 healthy men, n = 9 each of genotype DD, ID and II, in a parallel group study design. 2. Before treatment serum ACE activity differed significantly between the genotypes, with serum ACE activity 56% higher in DD than II subjects, and the genotype explaining 40% of between-subject variance in serum ACE activity. 3. After oral enalapril 10 mg the absolute fall in serum ACE activity was significantly larger in DD than II subjects at 2, 4, and 6 h (by 9.0 (95% CI 0.7-17.2), 10.7 (3.8-17.6), and 9.7 (2.8-16.6) nmol ml-1 min-1 respectively), but not at 24 h (fall in II > DD by 1.1 (-8.9 to 6.7) nmol ml-1 min-1). 4. Serum ACE activity remained significantly related to the ACE genotype at each time-point after enalapril, with the genotype explaining 22-46% of between-subject variance in serum ACE. 5. Falls in mean arterial pressure in response to enalapril were not significantly related to the ACE genotype, with the average fall over 6 h in DD > II genotype by 0.7 mm Hg (95% CI -5.5 to 4.1). 6. Blood pressure responses to enalapril did not correlate significantly with the initial serum ACE, or the absolute or percent reductions in serum ACE activity after enalapril.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

Effects of various factors on steady-state plasma concentrations of risperidone and 9-hydroxyrisperidone: lack of impact of MDR-1 genotypes.

AIMS: An in vitro study has suggested that risperidone is a substrate of P-glycoprotein, which is coded by MDR-1 gene. Thus, we studied the effects of major polymorphisms of the MDR-1 gene on plasma drug concentrations. METHODS: Subjects were 85 schizophrenic patients receiving 3 mg twice daily of risperidone. Sample collections were conducted 12 h after the bedtime dosing. Plasma concentrations of risperidone and 9-hydroxyrisperidone were quantified using LC/MS/MS. MDR-1 genotypes (C3435T and G2677T/A) and CYP2D6 genotypes were identified using PCR-RFLP methods. RESULTS: There was no difference in geometric mean (95% CI) of steady-state plasma concentration of risperidone between C3435T genotypes [C/C, C/T, T/T; 2.06 (1.63, 6.47), 2.96 (3.10, 7.91), 2.28 (1.81, 8.04) ng ml(-1), P = 0.759] or G2677T/A genotypes [G/G, G/T or A, T or A/T or A; 1.62 (0.08, 6.07), 2.64 (3.25, 7.10), 2.71 (2.77, 8.72) ng ml(-1), P = 0.625] or 9-hydroxyrisperidone between C3435T genotypes [38.3 (33.7, 50.1), 34.9 (32.9, 42.0), 35.7 (31.7, 42.3) ng ml(-1), P = 0.715] or G2677T/A genotypes [40.6 (33.0, 51.8), 35.0 (33.3, 42.4), 36.1 (32.8, 47.2) ng ml(-1), P = 0.601]. Multiple regression analyses including CYP2D6 genotypes, sex, and age revealed that steady-state plasma concentration of risperidone correlated with the number of mutated alleles for CYP2D6 (standardized partial correlation coefficients (beta) = 0.540, P < 0.001) and those of 9-hydroxyrisperidone (standardized beta = 0.244, P = 0.038) and active moiety (standardized beta = 0.257, P = 0.027) correlated with age. CONCLUSIONS: These findings suggest that the MDR-1 variants are not associated with steady-state plasma concentration of risperidone or 9-hydroxyrisperidone, but CYP2D6 genotypes and age are determinants of these concentrations.

Adolescent↗