Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Exosomal glypican-1 discriminates pancreatic ductal adenocarcinoma from chronic pancreatitis

BACKGROUND AND AIMS

Pancreatic ductal adenocarcinoma (PDAC) diagnosis can be difficult in a chronic pancreatitis (CP) background, especially in its mass forming presentation. We aimed to assess the accuracy of glypican-1-positive circulating exosomes (GPC1+crExos) to distinguish PDAC from CP versus the state-of-the-art CA 19-9 biomarker.

METHODS

This was a unicentric prospective cohort. Endoscopic ultrasound with fine-needle aspiration or biopsy and blood tests (GPC1+crExos and serum CA 19-9) were performed.

RESULTS

The cohort comprised 60 PDAC and 29 CP (7 of which mass forming - MF) patients. Median levels of GPC1+crExos were significantly higher in PDAC (99.7%) versus CP (28.4%; p<0.0001) with an AUROC of 0.96 with 98.3% sensitivity and 86.2% specificity for a cut-off of 45.0% (p<0.0001); this outperforms CA 19-9 AUROC of 0.82 with 78.3% sensitivity and 65.5% specificity at a cut-off of 37 U/mL (p<0.0001). The superiority of% GPC1+crExos over CA 19-99 in differentiating PDAC from CP was observed in both early (stage I) and advanced tumors (stages II-IV).

CONCLUSION

Levels of GPC1+crExos coupled to beads enable differential diagnosis between PDAC and CP including its mass-forming presentation.

[Frailty of the elderly and physical activity in general practice: A prospective study]

INTRODUCTION

Frailty is a transient and reversible condition that can lead to significant morbidity and mortality and to the loss of autonomy. It is one of the key issues in public health and the prevention of addiction. Physical activity is often described as a protective factor against addiction and as a factor in limiting frailty. Our goal is to analyze the relationship between physical activity and frailty among the elderly METHODS: A cross-sectional observational study was carried out in three general practice clinics located in the French department of Eure. Patients aged 65 and over were included during a consultation with their GP. Dependent patients under the ADL scale were excluded. Level of physical activity was assessed by the Ricci and Gagnon questionnaire, which defines an active profile as a score≥18 points. Frailty was sought out by the Fried scale and the SEGA A grid. Multivariate analysis was performed to adjust frailty scores to age, gender, and level of physical activity.

RESULTS

Out of the 70 patients included, 36 were active (51%) and 34 inactive (49%). They were predominantly female with 47 women (67%). Average age was 75.3years. Twelve patients were diagnosed as frail (17%) with the Fried scale and 24 (34%) with the SEGA A grid. Bivariate analysis revealed a greater frailty according to the Fried criteria in the inactive than in the active patients (mean for active patients 0.56 IC95 [0.31; 0.80], compared to 1.76 [1.21; 2.32] in the inactive patients, p<0.0001). The difference in mean was likewise significant regarding the SEGA A score (6.42 IC95 [5.34, 7.49] in the active population, as opposed to 8.65 IC95 [7.15, 10.15] among the inactive, p=0.017). In multivariate analysis, the Fried scale was primarily influenced by age and ADL, while the SEGA score was impacted by female gender and level of physical activity.

CONCLUSION

Physical activity seems to have a positive effect on frailty. It would be interesting to propose systematic screening for frailty in general medicine and to institute preventive measures, including physical activity. Initiatives encouraging and promoting seniors' physical activity should be strengthened.

A256 TRENDS IN THE PREVALENCE AND SEVERITY OF ANEMIA IN PEDIATRIC PATIENTS WITH INFLAMMATORY BOWEL DISEASE IN THE LAST DECADE

Background

Anemia is one of the most common extraintestinal manifestations in patients with inflammatory bowel disease (IBD) at diagnosis. Studies have shown that anemia was associated with low levels of quality of life, which improves with the correction of anemia in adults. Recent data have shown an increase in the incidence and severity of pediatric IBD.

Aims

To investigate the prevalence of anemia in children at diagnosis of IBD and the trends in the past decade. The secondary aim was to investigate the associations between hemoglobin (Hb) levels and disease characteristics.

Methods

Eligible patients (age ≤18 years, diagnosed with IBD from 2009 to 2018) were retrospectively identified through our IBD database. Disease localization and phenotype were defined according to the Paris Classification of IBD. Anemia was defined by Hb levels according to WHO targets. The annual prevalence of anemia was calculated according to subtype (inflammatory vs iron deficiency). The Pediatric Crohn’s Disease Activity Index (PCDAI) and the Pediatric Ulcerative Colitis Activity Index (PUCAI) were used to assess the disease severity at diagnosis.

Results

We included 887 patients (439 females), mean (SD) age of 13.1 (3.4) years. Of these, 519 (58.5%) were identified with anemia within 30 days of diagnosis. The median (IQR) Hb level was 108 (98 -114) g/dL. Severe anemia (&lt; 70 g/dL) was present in 1.8 % of patients. The prevalence of anemia at diagnosis remained relatively stable ranging from 60.2% in 2009 to 60.4% in 2018. The annual proportion of inflammatory vs iron-deficiency anemia is displayed in figure 1. Anemia was more prevalent in Crohn’s disease (CD) (62.2%) than Ulcerative colitis (UC) (57.9%) or IBD-unclassified (39.6%). The disease severity scores were higher in those with anemia. The median (IQR) PCDAI and PUCAI were respectively 37.5 (27.5–47.5) and 55.0 (40.0–65.0) in the anemic group as compared to 27.5 (20.0–37.50) and 35.0 (25.0–55.0) in the non-anemic group; P&lt;0.0001. Patients with anemia had a lower BMI z-score [median (IQR) -0.84 (-1.84 - 0.08)] than the non-anemic patients [median (IQR) -0.38 (-1.21 - 0.43)]; P&lt;0.001. The prevalence of anemia correlated significantly with disease location: upper intestinal involvement [L4a(67.7%) L4b(63.6%) L4aL4b(60.7%) none (52.8%)] P = 0.024 for CD; for UC [E1(21.1%) E2(44.4%) E3(75.0%) E4 (71.1%)] P&lt;0.0001. A moderate correlation was found between Hb levels and C-reactive protein (r= -0.312, 95% CI: -0.378 to -0.243, P&lt;0.0001).

Conclusions

Anemia remains a prevalent symptom in pediatric patients with IBD, and it is correlated with the extent of intestinal involvement and disease severity. The impact of anemia at Diagnosis and during follow-up on the levels of quality of life and physical activity is currently under investigation.

Funding Agencies

None

Etanercept-induced granulomatous hepatitis as a rare cause of abnormal liver tests

The authors report the case of a 76 year-old man with rheumatoid arthritis treated with prednisolone and etanercept. The patient was seen for persistent changes in liver tests lasting for six months, with a mixed pattern. The patient denied intake of new drugs or dietary/herbal supplements. Imaging studies showed mild steatosis. Additional study for chronic liver diseases only revealed positivity for anti-nuclear antibodies. Liver biopsy revealed noncaseating granulomas in some portal tracts. Consequent etiologic study for granulomatous diseases showed negative or normal results. So it was decided to suspend etanercept, with a subsequent gradual improvement on analytical parameters that normalized three months later. To date, only one case of granulomatous liver disease associated with an anti-TNF agent was described in the literature. This case also raises the question whether the development of granulomatous processes associated with anti-TNF agents has been underdiagnosed due to the presence of other concomitant immunosuppressant therapies.

Kinetics of acid-base parameters in conventional hemodialysis

Details about the acid-base changes in hemodialysis are scarce in the literature but are potentially relevant to adequate management of patients. We addressed the acid-base kinetics during hemodialysis and throughout the interdialytic period in a cross-sectional study of adults undergoing conventional hemodialysis. Samples for blood gas analysis were obtained from the arterial limb of the arteriovenous fistula before the first session of the week (HD1), immediately at the end of HD1, and on sequential collections at 15, 30, 45, 60, and 120 min post-HD1. Additional blood samples were collected after ∼20 h following the end of the first dialysis and immediately prior to the initiation of the second dialysis of the week. Thirty adult patients were analyzed (55±15 years, 50% men, 23% diabetic; dialysis vintage 69±53 months). Mean serum bicarbonate levels increased at the end of HD1 (22.3±2.7 mEq/L vs 17.5±2.3 mEq/L, P<0.001) and remained stable until 20 h after the end of the session. The mean values of pCO2 before HD1 were below reference and at 60 and 120 min post-HD1 were significantly lower than at the start (31.3±2.7 mmHg and 30.9±3.7 mmHg vs 34.3±4.1 mmHg, P=0.041 and P=0.010, respectively). The only point of collection in which mean values of pCO2 were above 35 mmHg was 20 h post-dialysis. Serum bicarbonate levels remained stable for at least 20 h after the dialysis sessions, a finding that may have therapeutic implications. During dialysis, the respiratory response for correction of metabolic acidosis (i.e., pCO2 elevation) was impaired.

Long-Term Safety of In Utero Exposure to Anti-TNFα Drugs for the Treatment of Inflammatory Bowel Disease: Results from the Multicenter European TEDDY Study

OBJECTIVES

The long-term safety of exposure to anti-tumor necrosis factor (anti-TNFα) drugs during pregnancy has received little attention. We aimed to compare the relative risk of severe infections in children of mothers with inflammatory bowel disease (IBD) who were exposed to anti-TNFα drugs in utero with that of children who were not exposed to the drugs.

METHODS

Retrospective multicenter cohort study. Exposed cohort: children from mothers with IBD receiving anti-TNFα medication (with or without thiopurines) at any time during pregnancy or during the 3 months before conception. Non-exposed cohort: children from mothers with IBD not treated with anti-TNFα agents or thiopurines at any time during pregnancy or the 3 months before conception. The cumulative incidence of severe infections after birth was estimated using Kaplan-Meier curves, which were compared using the log-rank test. Cox-regression analysis was performed to identify potential predictive factors for severe infections in the offspring.

RESULTS

The study population comprised 841 children, of whom 388 (46%) had been exposed to anti-TNFα agents. Median follow-up after delivery was 47 months in the exposed group and 68 months in the non-exposed group. Both univariate and multivariate analysis showed the incidence rate of severe infections to be similar in non-exposed and exposed children (1.6% vs. 2.8% per person-year, hazard ratio 1.2 (95% confidence interval 0.8-1.8)). In the multivariate analysis, preterm delivery was the only variable associated with a higher risk of severe infection (2.5% (1.5-4.3)).

CONCLUSIONS

In utero exposure to anti-TNFα drugs does not seem to be associated with increased short-term or long-term risk of severe infections in children.

The role of targeted BRCA1/BRCA2 mutation analysis in hereditary breast/ovarian cancer families of Portuguese ancestry

We report the analysis of altogether 1050 suspected hereditary breast/ovarian cancer (HBOC) families, 524 fully screened for BRCA1/BRCA2 mutations and 526 tested only for the most common mutations. Of the 119 families with pathogenic mutations, 40 (33.6%) had the BRCA2 c.156_157insAlu rearrangement and 15 (12.6%) the BRCA1 c.3331_3334del mutation, the former being specific of Portuguese ancestry and the latter showing a founder effect in Portugal. Interestingly, the two most common mutations were found in a significant proportion of the HBOC families with an a priori BRCAPRO mutation probability <10%. We recommend that all suspected HBOC families from Portugal or with Portuguese ancestry, even those fulfilling moderately stringent clinical-criteria for genetic testing, should be specifically analyzed for the two most common BRCA1/BRCA2 founder mutations, and we here present a simple method for this first tier test. Screening of the entire coding regions of BRCA1 and BRCA2 should subsequently be offered to those families with a mutation probability ≥10% if none of those founder mutations are found.

The MSH2 c.388_389del mutation shows a founder effect in Portuguese Lynch syndrome families

The MSH2 c.388_389del mutation has occasionally been described in Lynch families worldwide. At the Portuguese Oncology Institute in Porto, Portugal, we have identified 16 seemingly unrelated families with this germline mutation. To evaluate if this alteration is a founder or a recurrent mutation we performed haplotype analysis in the 16 Portuguese index cases and 55 relatives, as well as in four index cases and 13 relatives reported from Germany, Scotland, England, and Argentina. In the Portuguese families we observed a shared haplotype of approximately 10 Mb and all were originated from the north of Portugal. These results suggest that this alteration is a founder mutation in Portugal with a relatively recent origin. In the reported families outside Portugal with this mutation different haplotype backgrounds were observed, supporting the hypothesis that it occurred de novo on multiple occasions. We also conclude that the high proportion of families with the MSH2 c.388_389del mutation indicates that screening for this alteration as a first step may be cost-effective in the genetic testing of Lynch syndrome suspects of Portuguese ancestry, especially those originating from the north of Portugal.

Disease knowledge and attitudes toward predictive testing and prenatal diagnosis in families with Machado-Joseph disease from the Azores Islands (Portugal)

OBJECTIVE

Machado-Joseph disease (MJD) reaches its highest prevalence world-wide in the Azores, thus constituting a public health problem in these islands. The aim of the study was thus to (1) determine the level of knowledge about the disease; (2) estimate the expected level of request for predictive testing, and (3) analyse the intentions of at-risk individuals concerning their reproductive decisions.

METHODS

A questionnaire on these points was distributed to 42 affected and 36 at-risk individuals.

RESULTS

As expected, the educational level of the respondents was significantly associated with the level of knowledge about the disease. The survey indicated that 83.3% of the at-risk individuals would make use of predictive test and that 77.8% would make use of prenatal diagnosis. Of the latter, 36.1% would terminate pregnancy if confronted with a positive result for the fetus.

CONCLUSIONS

The level of knowledge about MJD in the Azorean families is considered to be fair. Although the actual behavior can prove to be different from the intentions put forward by at-risk individuals based solely on the results of this study we can estimate that the request for a predictive test would be quite high. The intentions expressed by at-risk individuals seem to indicate that the prenatal diagnosis will have an effect on their reproductive decisions. Results obtained certify the importance of implementing genetic testing for MJD in the Azores.

MUC1 gene polymorphism in the gastric carcinogenesis pathway

MUC1 like most mucin genes shows extensive length polymorphism in the central core region. In a previous study it was shown that individuals with small MUC1 alleles/genotypes have an increased risk for development of gastric carcinoma. Our aim was to see if MUC1 gene polymorphism was involved in susceptibility for the development of conditions that precede gastric carcinoma: chronic atrophic gastritis (CAG) and intestinal metaplasia (IM). We evaluated MUC1 polymorphism in a population of 174 individuals with chronic gastritis (CG) displaying (CAG) and/or intestinal metaplasia (IM). The population of patients with CG shows MUC1 allele frequencies significantly different from the gastric carcinoma patients and blood donors population. A significantly lower frequency of CAG and IM was observed in MUC1 VNTR heterozygotic patients. Within the group of patients with IM, MUC1 large VNTR homozygotes show a significantly higher frequency of complete IM while small VNTR homozygotes show a significantly higher frequency of incomplete IM. These findings show that MUC1 polymorphism may define different susceptibility backgrounds for the development of conditions that precede gastric carcinoma: chronic atrophic gastritis (CAG) and intestinal metaplasia (IM).

Helicobacter pylori genotypes may determine gastric histopathology

The outcome of Helicobacter pylori infection has been associated with specific virulence-associated bacterial genotypes. The present study aimed to investigate the gastric histopathology in Portuguese and Colombian patients infected with H. pylori and to assess its relationship with bacterial virulence-associated vacA, cagA, and iceA genotypes. A total of 370 patients from Portugal (n = 192) and Colombia (n = 178) were studied. Corpus and antrum biopsy specimens were collected from each individual. Histopathological features were recorded and graded according to the updated Sydney system. H. pylori vacA, cagA, and iceA genes were directly genotyped in the gastric biopsy specimens by polymerase chain reaction and reverse hybridization. Despite the significant differences between the Portuguese and Colombian patient groups, highly similar results were observed with respect to the relation between H. pylori genotypes and histopathology. H. pylori vacA s1, vacA m1, cagA+ genotypes were significantly associated with a higher H. pylori density, higher degrees of lymphocytic and neutrophilic infiltrates, atrophy, the type of intestinal metaplasia, and presence of epithelial damage. The iceA1 genotype was only associated with epithelial damage in Portuguese patients. These findings show that distinct H. pylori genotypes are strongly associated with histopathological findings in the stomach, confirming their relevance for the development of H. pylori-associated gastric pathology.

Courtship song genes and speciation in sand flies

Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) is a vector of visceral leishmaniasis in the Americas and it might represent a complex of sibling species. Reproductive isolation between closely related species often involves differences in courtship behaviour. cacophony (cac) and period (per) are two Drosophila genes that control features of the "lovesong" males produce during courtship that has been implicated in the sexual isolation between closely related species. We are using gene fragments from L. longipalpis' homologues of these two genes to study the speciation process in this putative species complex.

Mucins and mucin-associated carbohydrate antigens expression in gastric carcinoma cell lines

Mucins are high-molecular-mass glycoproteins with high carbohydrate content and marked heterogeneity both in the apoprotein and in the oligosaccharide side chains. Mucin genes are expressed in a regulated manner, namely in the human stomach. The first aim of the present study was to characterise the expression of mucins and mucin-associated carbohydrate antigens in seven gastric carcinoma cell lines, and to compare their expression profiles with those of normal gastric tissues and human gastric carcinomas. Secondly, we aimed to see whether or not there is an association between the expression of mucins and mucin-associated carbohydrate antigens. Our results show that mucin expression in gastric carcinoma cell lines: (a) follows in part the mucin expression profile of normal gastric mucosa and gastric carcinomas with wide expression of MUC1 and MUC5AC; (b) parallels the aberrant pattern of mucin expression observed in human gastric carcinomas with occasional expression of MUC2, MUC3, MUC4 and MUC5B; (c) does not include, at least in our series, the expression of MUC6 mucin; and (d) follows in part the differentiation pattern of the carcinomas from which the cell lines originated, keeping S-Tn expression in cell lines derived from glandular carcinomas. Our results further demonstrate that there is no apparent relationship between the mucin core proteins and the simple mucin-type or Lewis carbohydrate antigens.

MUC1 gene polymorphism does not explain the different incidence of gastric cancer in Portugal and Denmark

MUC1 is a highly polymorphic mucin type glycoprotein expressed on the surface of many epithelia, including gastric mucosa, and is present in several body fluids and mucous secretions. A genetic polymorphism due to variation in length of a 60 bp tandemly repeated sequence domain constitutes more than half of the coding region of the glycoprotein. We demonstrated previously in a Portuguese population sample that the frequency of small MUC1 alleles is increased in patients with gastric carcinoma, suggesting that the possession of small MUC1 alleles confers increased risk for gastric carcinoma development. This finding raised the possibility that the very high prevalence of gastric carcinoma in Portugal could be partly due to a high frequency of small MUC1 alleles in the Portuguese population. In the present study we compared the MUC1 allele distribution in a population of Danish blood donors with the distribution in a population of Portuguese blood donors. The frequency of small MUC1 alleles was significantly higher in the Danish than in the Portuguese sample, thus failing to lend support to the hypothesis that a relatively higher frequency of the small MUC1 alleles might account for the high prevalence of gastric carcinoma in Portugal when compared to Denmark.

Analysis of FMR1 and flanking microsatellite markers in normal and fragile X chromosomes in Portugal: evidence for a "protector" haplotype

In order to look for linkage disequilibrium between the fragile X locus and its flanking markers, we analysed the FRAXAC1 and DXS548 microsatellites in normal and fragile X individuals of Portuguese origin. We observed differences in allele and haplotype frequencies between these two samples. Four haplotypes (A-2, C-2, C-5 and D-6) accounted for 76% of all fragile X chromosomes, whereas a single haplotype (C-7) accounted for 70% of the normal population and less than 3% of the fragile X chromosomes. Among the four observed high-risk haplotypes, A-2 and D-6 had been previously reported in other studies, but C-2 and C-5 seem characteristic of Portuguese patients, as suggested by the high frequency (38%) in fragile X chromosomes and virtual absence in controls. In accordance with previous studies, a greater heterozygosity of the fragile X sample was noted when compared to that of controls. The high frequency of C-7 haplotype in the normal population and its virtual absence in the fragile X sample may reflect the existence of linkage disequilibrium between the two loci and/or selective advantage (protector effect) of this haplotype.