FUT2 Genotype Research Articles

Genetic and mechanistic evaluation of an individual with para-Bombay phenotype associated with a compound heterozygote comprising two novel FUT1 variants.

As is well documented, the para-Bombay phenotype is typically characterized by the reduction or absence of ABH antigens on red blood cells but the presence of corresponding antigens in saliva. Herein, the underlying molecular mechanism of an individual with para-Bombay AB phenotype combined with two novel variants of the FUT1 gene was investigated. ABH antigens and antibodies were detected in the serum of the proband using conventional serological methods. The coding region nucleotides of the ABO, FUT1, and FUT2 genes were directly sequenced by polymerase chain reaction. Moreover, the FUT1 haploid type in the proband was analyzed by TA clone sequencing. The 3D structure of wild-type and mutant fucosyltransferases were simulated and analyzed using Phyre2 and Pymol software. Lastly, the effect of missense substitution on the function of fucosyltransferase was predicted by the Polymorphism Phenotyping algorithm (PolyPhen-2) and MutationTaster. ABH antigens were noted to be absent on the surface of red blood cells of the proband. The ABO genotype was ABO*A1.02/ABO*B.01, while the FUT2 genotype was FUT2*01/FUT2*c.357T. Interestingly, two novel missense variants (c.289G>A, p.Ala97Thr and c.575G>C, p.Arg192Pro) and one synonymous SNP (c.840G>A) were identified in the FUT1 gene. Furthermore, c.289G>A was detected in one haploid type, whereas c.575G>C and c.840G>A were discovered in another haploid type. Meanwhile, in silico analysis revealed that amino acid substitution caused by missense variants altered the partial spatial structure of the α-helices where residues 97 and 298 were located using 3D homology modeling software. Finally, both missense variants were defined as probably damaging based on PolyPhen-2 prediction. Two novel FUT1 variants were identified in a Chinese individual with para-Bombay AB phenotype, which can expand our understanding of the molecular mechanism underlying the para-Bombay phenotype and contribute to improving the safety of blood transfusion.

Host genetic regulation of human gut microbial structural variation

Although the impact of host genetics on gut microbial diversity and the abundance of specific taxa is well established1–6, little is known about how host genetics regulates the genetic diversity of gut microorganisms. Here we conducted a meta-analysis of associations between human genetic variation and gut microbial structural variation in 9,015 individuals from four Dutch cohorts. Strikingly, the presence rate of a structural variation segment in Faecalibacterium prausnitzii that harbours an N-acetylgalactosamine (GalNAc) utilization gene cluster is higher in individuals who secrete the type A oligosaccharide antigen terminating in GalNAc, a feature that is jointly determined by human ABO and FUT2 genotypes, and we could replicate this association in a Tanzanian cohort. In vitro experiments demonstrated that GalNAc can be used as the sole carbohydrate source for F. prausnitzii strains that carry the GalNAc-metabolizing pathway. Further in silico and in vitro studies demonstrated that other ABO-associated species can also utilize GalNAc, particularly Collinsella aerofaciens. The GalNAc utilization genes are also associated with the host’s cardiometabolic health, particularly in individuals with mucosal A-antigen. Together, the findings of our study demonstrate that genetic associations across the human genome and bacterial metagenome can provide functional insights into the reciprocal host–microbiome relationship.

The Combined Effect of Infant and Mother Secretor Status on Infant Susceptibility to Viral Gastroenteritis and Celiac Disease

Celiac disease is a prevalent autoimmune disorder with a rising incidence of 7.5% annually during the second half of the 20<sup>th</sup> century and the 21<sup>st</sup> century. Not all genetically susceptible individuals that carry the risk alleles HLA DQ2 and DQ8 go on to develop celiac disease, suggesting that there may be other environmental triggers that contribute to the development of celiac disease in genetically susceptible individuals. Gastroenteritis during infancy has been shown to be associated with increased risk of celiac disease. Secretor status, per the FUT2 genotype, and subsequent alterations in the microbiota, is associated with risk of gastroenteritis in infants. This review investigates the literature from January 2010 to June 2022 to determine the combined effect of secretor status and viral gastroenteritis on the development of celiac disease.<strong> </strong>Mothers with the secretor phenotype and infants with the non-secretor phenotype provided the most protection against particular strains of gastroenteritis and celiac disease. Both the maternal and infant secretor status, as well as the infant’s Lewis status and ABO blood group can influence the infant’s susceptibility to different viral strains, which cause gastroenteritis. Gastroenteritis caused by viral infections can damage intestinal epithelial cells, cause dysbiosis, and affect pro-inflammatory cytokines, which exacerbate celiac disease onset. Understanding the effect of secretor status and gastroenteritis on celiac disease may provide a novel approach to early screening and preventative strategies to reduce risk factors that contribute to the onset of celiac disease.

DNA quality from buccal swabs in neonates: comparison of different storage time

BACKGROUND Genomic medicine has great potential for diagnoses, disease prediction, and targeted treatment. Buccal swabs are a suitable non-invasive method for neonates to obtain DNA samples. Due to Indonesia's geographical conditions, samples require a prolonged time to reach the genetic laboratory. This study aimed to compare the DNA quality of buccal swabs in neonates between immediate and after-storage extraction.
 METHODS This study was part of a study about the profile of human milk oligosaccharide and FUT2 genotype in Indonesian mother-infant dyads consisting of 20 neonates. 1 swab stick for each participant was taken using a standardized buccal swabbing protocol and divided into 2 isovolume aliquots, which were grouped into the immediate (extraction was performed within 3 days after sampling) and storage groups (extraction was performed on the 14th day after storage in 4°C). DNA yield and purity A260/280 ratio were measured by spectrophotometry. The PCR amplification and Sanger sequencing were performed to validate the DNA isolate quality for downstream application.
 RESULTS The DNA yield for the immediate group was similar compared with the storage group (9.50 [4.89] versus 9.10 [5.05] µg), p = 0.659, as well as DNA purity A260/280 (1.58 [0.24] versus 1.56 [0.28]), p = 0.785. PCR and sequencing of FUT2 results also showed similar quality between both groups.
 CONCLUSIONS The similar DNA quality and sequencing results between immediate and storage extraction confirmed that buccal swabs could be stored for 2 weeks, allowing ample time for sample shipping from remote areas to the laboratory.

Association between histo-blood group antigens and Pseudomonas aeruginosa-associated diarrheal diseases.

Pseudomonas aeruginosa is not a common enteric pathogen. The association between human histo-blood group antigens (HBGAs) and P. aeruginosa enteric infection has not yet been studied. We collected stool samples from healthy children under 2 years of age for P. aeruginosa gut colonization rate. Saliva samples were collected from patients with P. aeruginosa-associated diarrheal diseases and normal healthy children. Genomic DNA was extracted from saliva samples for ABO blood group typing and FUT2 genotyping. Lewis phenotype was detected using ELISA assay. A total of 85 patients with P. aeruginosa-associated diarrheal diseases and 105 healthy children were enrolled for collecting saliva specimens. The stool colonization rate was 5/101 (5%) in healthy children, 4/58 (6.9%) in infants, and 1/43 (2.3%) in children 1-2 years old, respectively. Blood group A was more frequent in patients with P. aeruginosa-associated diarrheal diseases 24/77 (31.2%) than in healthy children 18/102 (17.6%) (P=0.035). All patients and healthy children were secretor positive. The distribution of weak-secretor genotype Se385/Se385 was 23/84 (27.4%) in patients with P. aeruginosa-associated diarrheal diseases and 17/104 (16.3%) in healthy children, respectively (P=0.06). Patients with P. aeruginosa-associated diarrheal diseases had a higher percentage of Lea+b+phenotype 25/81 (30.9%) than healthy children 17/105 (16.2%) (P=0.018). There was no association between ABO or secretor or Lewis status with the clinical severity of P. aeruginosa-associated diarrheal diseases. Infants had a higher gut P. aeruginosa colonization rate than children. Children with blood group A and Lea+b+phenotype are prone to P. aeruginosa-associated diarrheal diseases.

Estimation of Lewis Blood Group Status by Fluorescence Melting Curve Analysis in Simultaneous Genotyping of c.385A>T and Fusion Gene in FUT2 and c.59T>G and c.314C>T in FUT3

Lewis blood group status is determined by two fucosyltransferase activities: those of FUT2-encoded fucosyltransferase (Se enzyme) and FUT3-encoded fucosyltransferase (Le enzyme). In Japanese populations, c.385A>T in FUT2 and a fusion gene between FUT2 and its pseudogene SEC1P are the cause of most Se enzyme-deficient alleles (Sew and sefus), and c.59T>G and c.314C>T in FUT3 are tag SNPs for almost all nonfunctional FUT3 alleles (le59, le59,508, le59,1067, and le202,314). In this study, we first conducted a single-probe fluorescence melting curve analysis (FMCA) to determine c.385A>T and sefus using a pair of primers that collectively amplify FUT2, sefus, and SEC1P. Then, to estimate Lewis blood group status, a triplex FMCA was performed with a c.385A>T and sefus assay system by adding primers and probes to detect c.59T>G and c.314C>T in FUT3. We also validated these methods by analyzing the genotypes of 96 selected Japanese people whose FUT2 and FUT3 genotypes were already determined. The single-probe FMCA was able to identify six genotype combinations: 385A/A, 385T/T, sefus/sefus, 385A/T, 385A/sefus, and 385T/sefus. In addition, the triplex FMCA successfully identified both FUT2 and FUT3 genotypes, although the resolutions of the analysis of c.385A>T and sefus were somewhat reduced compared to that of the analysis of FUT2 alone. The estimation of the secretor status and Lewis blood group status using the form of FMCA used in this study may be useful for large-scale association studies in Japanese populations.

Microbiota-induced regulatory T cells associate with FUT2-dependent susceptibility to rotavirus gastroenteritis.

The FUT2 α1,2fucosyltransferase contributes to the synthesis of fucosylated glycans used as attachment factors by several pathogens, including noroviruses and rotaviruses, that can induce life-threatening gastroenteritis in young children. FUT2 genetic polymorphisms impairing fucosylation are strongly associated with resistance to dominant strains of both noroviruses and rotaviruses. Interestingly, the wild-type allele associated with viral gastroenteritis susceptibility inversely appears to be protective against several inflammatory or autoimmune diseases for yet unclear reasons, although a FUT2 influence on microbiota composition has been observed. Here, we studied a cohort of young healthy adults and showed that the wild-type FUT2 allele was associated with the presence of anti-RVA antibodies, either neutralizing antibodies or serum IgA, confirming its association with the risk of RVA gastroenteritis. Strikingly, it was also associated with the frequency of gut microbiota-induced regulatory T cells (Tregs), so-called DP8α Tregs, albeit only in individuals who had anti-RVA neutralizing antibodies or high titers of anti-RVA IgAs. DP8α Tregs specifically recognize the human symbiont Faecalibacterium prausnitzii, which strongly supports their induction by this anti-inflammatory bacterium. The proportion of F. prausnitzii in feces was also associated with the FUT2 wild-type allele. These observations link the FUT2 genotype with the risk of RVA gastroenteritis, the microbiota and microbiota-induced DP8α Treg cells, suggesting that the anti-RVA immune response might involve an induction/expansion of these T lymphocytes later providing a balanced immunological state that confers protection against inflammatory diseases.

Audiologic Measures in an Indigenous Community with A2ML1- and FUT2-Related Otitis Media.

Background: Many indigenous peoples are at elevated risk for otitis media, however there is limited information on hearing loss due to OM in these communities. An Indigenous Filipino community that has previously been described with an elevated prevalence of OM that is due to rare A2ML1 variants and a common FUT2 variant underwent additional phenological testing. In this study, we describe the audiologic profiles in A2ML1- and FUT2-related otitis media and the validity of otoscopy and genotyping for A2ML1 and FUT2 variants in screening for otitis media and hearing loss. Method: We analyzed A2ML1 and FUT2 genotypes together with demographic, otologic and audiologic data from tympanometry and hearing level assessments of 109 indigenous individuals. Results: We confirmed previous findings of a spectrum of nonsyndromic otitis media as associated with A2ML1 variants. A2ML1 and FUT2 variants were associated with high-frequency hearing loss at 4000 Hz. As expected, young age was associated with flat tympanograms, and eardrum perforations due to chronic otitis media were associated with severe-to-profound hearing loss across frequencies. Adding A2ML1 or FUT2 genotypes improved the validity of otoscopy as a screening test to rule out moderate-to-profound hearing loss. Conclusion: Continued multi-disciplinary management and audiologic follow-up using tympanometry and screening audiometry are needed to document and treat otitis media and prevent permanent hearing loss in the indigenous community.

Genetic association of IL17 and the importance of ABO blood group antigens in saliva to COVID-19

The outbreak of COVID-19 caused by infection with SARS-CoV-2 virus has become a worldwide pandemic, and the number of patients presenting with respiratory failure is rapidly increasing in Japan. An international meta-analysis has been conducted to identify genetic factors associated with the onset and severity of COVID-19, but these factors have yet to be fully clarified. Here, we carried out genomic analysis based on a genome-wide association study (GWAS) in Japanese COVID-19 patients to determine whether genetic factors reported to be associated with the onset or severity of COVID-19 in the international meta-GWAS are replicated in the Japanese population, and whether new genetic factors exist. Although no significant genome-wide association was detected in the Japanese GWAS, an integrated analysis with the international meta-GWAS identified for the first time the involvement of the IL17A/IL17F gene in the severity of COVID-19. Among nine genes reported in the international meta-GWAS as genes involved in the onset of COVID-19, the association of FOXP4-AS1, ABO, and IFNAR2 genes was replicated in the Japanese population. Moreover, combined analysis of ABO and FUT2 genotypes revealed that the presence of oral AB antigens was significantly associated with the onset of COVID-19. FOXP4-AS1 and IFNAR2 were also significantly associated in the integrated analysis of the Japanese GWAS and international meta-GWAS when compared with severe COVID-19 cases and the general population. This made it clear that these two genes were also involved in not only the onset but also the severity of COVID-19. In particular, FOXP4-AS1 was not found to be associated with the severity of COVID-19 in the international meta-GWAS, but an integrated analysis with the Japanese GWAS revealed an association with severity. Individuals with the SNP risk allele found between IL17A and IL17F had significantly lower mRNA expression levels of IL17F, suggesting that activation of the innate immune response by IL17F may play an important role in the severity of SARS-CoV-2 infection.

Effect of host genetics on the gut microbiome in 7,738 participants of the Dutch Microbiome Project.

Host genetics are known to influence the gut microbiome, yet their role remains poorly understood. To robustly characterize these effects, we performed a genome-wide association study of 207 taxa and 205 pathways representing microbial composition and function in 7,738 participants of the Dutch Microbiome Project. Two robust, study-wide significant (P < 1.89 × 10-10) signals near the LCT and ABO genes were found to be associated with multiple microbial taxa and pathways and were replicated in two independent cohorts. The LCT locus associations seemed modulated by lactose intake, whereas those at ABO could be explained by participant secretor status determined by their FUT2 genotype. Twenty-two other loci showed suggestive evidence (P < 5 × 10-8) of association with microbial taxa and pathways. At a more lenient threshold, the number of loci we identified strongly correlated with trait heritability, suggesting that much larger sample sizes are needed to elucidate the remaining effects of host genetics on the gut microbiome.

A one-year study of human milk oligosaccharide profiles in the milk of healthy UK mothers and their relationship to maternal FUT2 genotype.

Human milk oligosaccharides (HMOs) are indigestible carbohydrates with prebiotic, pathogen decoy and immunomodulatory activities that are theorized to substantially impact infant health. The objective of this study was to monitor HMO concentrations over 1 year to develop a long-term longitudinal dataset. HMO concentrations in the breast milk of healthy lactating mothers of the Cambridge Baby Growth and Breastfeeding Study (CBGS-BF) were measured at birth, 2weeks, 6weeks, 3months, 6months and 12months postpartum. HMO quantification was conducted by high-performance anion-exchange chromatography with pulsed amperometric detection using a newly validated "dilute-and-shoot" method. This technique minimizes sample losses and expedites throughput, making it particularly suitable for the analysis of large sample sets. Varying patterns of individual HMO concentrations were observed with changes in lactation timepoint and maternal secretor status, with the most prominent temporal changes occurring during the first 3months. These data provide valuable information for the development of human milk banks in view of targeted distribution of donor milk based on infant age. Maternal FUT2 genotype was determined based on identification at single-nucleotide polymorphism rs516246 and compared with the genotype expected based on phenotypic markers in the HMO profile. Surprisingly, two mothers genotyped as secretors produced milk that displayed very low levels of 2'-fucosylated moieties. This unexpected discrepancy between genotype and phenotype suggests that differential enzyme expression may cause substantial variation in HMO profiles between genotypically similar mothers, and current genotypic methods of secretor status determination may require validation with HMO markers from milk analysis.

Altered gut microbiome in FUT2 loss‐of‐function mutants in support of personalized medicine for inflammatory bowel diseases

Background & Aims FUT2 encodes an α-1,2-fucosyltransferase required for the proper production of oligosaccharides and glycoproteins. The FUT2 polymorphism has been hypothesized to mediate a genetic mechanism to impact gut microbiota and consequently contribute to IBD pathogenesis, because of the high prevalence of loss-of-function polymorphisms of FUT2 and their association with IBD in genome-wide association studies. In this study, we investigated the role of the gut microbiota in IBD patients with FUT2 loss-of-function mutation. Method A total of 81 inflammatory bowel disease (IBD) patients were enrolled in 6th Affiliated Hospital of Sun Yat-sen University in Guangzhou, China between March 2016 and July 2018. To determine the genotypes of the patients at rs1047781 (A385T) and rs601338 (G428A) of the FUT2 gene, individuals were asked to provided blood samples. All participants were divided into 3 groups according to their genotypes: SeSe, Sese, and sese groups. For microbiome study, fecal DNA was collected and the V5-V6 region of the 16S rDNA was sequenced with a MiSeq platform. Metabolomics analysis targeting SCFA was performed by gas chromatography. Result The FUT2 genotypes are associated with specific gut microbiome compositions and functions in IBD patients. Differences in alpha-, beta-diversities, bacterial abundances at every taxonomic levels were observed between different FUT2 genotypes. Escherichia was significantly decreased in the gut of the sese patients. On the other hand, CD8+ inducing Alistipe and Phascolarctobacterium and Th17 inducing Erysipelotrichaceae were more abundant in sese patients suggests that these bacteria may explain the higher incidence of IBD among sese individuals. The PICRUSt functional analysis based on the 16S data showed that, several carbohydrate synthesis pathways were enriched in IBD patients with non-functional mutation of FUT2 (P<0.05). Interestingly, SCFA-producing bacteria in sese patient were not decreased although SCFA is protective against colon inflammation. Metabolomics analysis targeting SCFA confirmed this observation. Discussion Data presented here explained the association of non-secretor status with IBD. Our study supports the hypothesis that FUT2 loss-of-function genotype causes altered gut microbiota that is poised to the development of IBD. The identification of the T cell inducing species in this study contributes to the knowledge base for the development of personalized microbial intervention for IBD.

Estimation of secretor status of ABO antigens by high-resolution melting analysis of rs601338 (428G > A)

BackgroundFUT2 determines the secretor status of ABH antigens. Many lines of evidence suggest an association between secretor status and susceptibility to various clinical conditions. For this kind of study, large-scale genotyping of FUT2 is necessary. Because FUT2 has a pseudogene (SEC1) with high DNA sequence similarity and is rich in population-specific SNPs, we need to pay attention in designing the primers for genotyping FUT2. The se428 allele having a 428G > A nonsense SNP (W143X, rs601338) is the predominant non-secretor allele in Europeans, Latin Americans and Africans. On the other hand, se357,480,778del having the 778C > del frameshift SNP (P260Lfs*16, rs1799761) is almost exclusively found in Africans with frequencies of 1–4%.STUDY DESIGN AND METHODS: We developed high-resolution melting (HRM) analyses using short (69-bp for 428G > A, 65-bp for 778C > del) amplicons for genotyping two SNPs directly and validated the method by analyzing 95 Ghanaians whose FUT2 genotypes were previously determined. ResultsTwo sets of assays clearly discriminated three genotypes of 428G > A (G/G, G/A, A/A), and two genotypes of 778C > del (C/C, C/del). In addition, the results obtained for the 95 Ghanaians by HRM analysis were in full agreement with previous ones. ConclusionThe present HRM analysis reliably genotyped 428G > A. Thus, estimation of secretor status based on se428 using the present HRM analysis may be useful for large scale association studies of FUT2. In addition to 428G > A, genotyping of other causal polymorphisms for non-secretors with high frequency, as is the case with 778C > del for Africans, is desirable for more accurate estimation of the secretor status of the target populations.

Virus Etiology, Diversity and Clinical Characteristics in South African Children Hospitalised with Gastroenteritis.

Background: Viral gastroenteritis remains a major cause of hospitalisation in young children. This study aimed to determine the distribution and diversity of enteric viruses in children ≤5 years, hospitalised with gastroenteritis at Kalafong Provincial Tertiary Hospital, Pretoria, South Africa, between July 2016 and December 2017. Methods: Stool specimens (n = 205) were screened for norovirus GI and GII, rotavirus, sapovirus, astrovirus and adenovirus by multiplex RT-PCR. HIV exposure and FUT2 secretor status were evaluated. Secretor status was determined by FUT2 genotyping. Results: At least one gastroenteritis virus was detected in 47% (96/205) of children. Rotavirus predominated (46/205), followed by norovirus (32/205), adenovirus (15/205), sapovirus (9/205) and astrovirus (3/205). Norovirus genotypes GI.3, GII.2, GII.3, GII.4, GII.7, GII.12, GII.21, and rotavirus strains G1P[8], G2P[4], G2P[6], G3P[4], G3P[8], G8P[4], G8P[6], G9P[6], G9P[8] and sapovirus genotypes GI.1, GI.2, GII.1, GII.4, GII.8 were detected; norovirus GII.4[P31] and rotavirus G3P[4] predominated. Asymptomatic norovirus infection (GI.3, GI.7, GII.4, GII.6, GII.13) was detected in 22% of 46 six-week follow up stools. HIV exposure (30%) was not associated with more frequent or severe viral gastroenteritis hospitalisations compared to unexposed children. Rotavirus preferentially infected secretor children (p = 0.143) and norovirus infected 78% secretors and 22% non-secretors. Conclusion: Rotavirus was still the leading cause of gastroenteritis hospitalisations, but norovirus caused more severe symptoms.

Urgent Transfusion in a New Patient with Rare Blood Type

Background/Case Studies: Bombay is a rare blood group characterized by the absence of H substance at the surface of RBCs leading to naturally occurring anti-H antibodies. Anti-H presents the risk of severe hemolytic transfusion reactions in these patients. The case presented is of a 32-year-old female of Middle Eastern origin, who presented with a traumatic vertebral fracture with spinal cord compression and required urgent neurosurgery. Her presenting hemoglobin was 84 g/L. She had no previous group and screen on record, had never been transfused and had a history of a remote miscarriage. Study Design/Methods: Forward blood group with an automated gel-method instrument revealed the following reactions: negative with anti-A, unable to interpret (?) with anti-B, 4+ with anti-D. Reverse grouping revealed the following reactions: 4+ with A1-cells and an unexpected 1+ with B-cells. The antibody screen and 11 cell panel in gel (Micro Typing Systems) 2+; the panel, with enhancement reacted 3+ in Ficin. The auto control was negative. A second panel and pre-warm panel produced the same findings. An antibody reacting at 37C against a high-frequency antigen was suspected. Patient specimen was sent for investigation to the reference lab (RL), which performed blood group by manual tube test, antibody identification with panels by manual tube PEG-IAT method; RL also sent a sample for ABH sequencing (Sanger). Results/Findings: A thawed frozen plasma sample from a previous Bombay patient 12 years prior showed no reactivity against the patient's RBCs; positive control included. A frozen Bombay RBC unit was ordered urgently from the blood supplier and was crossmatch compatible. The patient underwent surgery and was transfused with a single unit of RBC for peri-operative bleeding. She was treated with erythropoietin and IV iron post-operatively and did not require any further transfusions. The investigation at the RL showed mixed field reaction on forward blood typing with anti-B and anti-A,B and negative reaction with anti-A commercial reagents. The RL reverse grouping showed 4+ with all O H+ and A1 red cells, but 2+ with B cells. The autocontrol and group O H- cells did not react, confirming anti-H and suggesting Para-Bombay group. ABH sequencing revealed a normal B allele (ABO*B.01) while genotyping of FUT1 revealed a null allele (FUT1*01N.12) and weak H allele (FUT1*01W.23). FUT2 genotyping (FUT2*01N.02) predicted a nonsecretor (sese) phenotype. Conclusions: This patient with non-secretor status, variant H production, clinically significant anti-H, greatly reduced B antigen expression, should be treated as a Bombay (Oh) for transfusion purposes. She was counselled and provided with an antibody card and a letter. This case illustrates the importance of timely communication with the clinical team about the risks and benefits of transfusion pending antibody identification, as it could have proved fatal in this case. Figure Disclosures Pavenski: Bioverativ:Research Funding;Shire/Takeda:Honoraria;Octapharma:Research Funding;Alexion:Honoraria, Research Funding;Sanofi:Research Funding;Ablynx/Sanofi:Honoraria, Research Funding.

Maternal FUT2 genotype in relation to risk of acute infections and rotavirus vaccine shedding in infancy

The human FUT2 gene codes fucosyltransferase2, an enzyme that catalyzes the production and secretion of H‐antigen in bodily fluids and tissues. FUT2 status has been associated with risk of infection for some pathogens. In addition, mothers who are homozygous positive or heterozygous for the FUT2 gene produce a class of oligosaccharides in their milk that can act as decoy receptors for some selected pathogens. The link between maternal FUT2 status and illnesses in breast‐fed infants is not clear.The Pediatric Respiratory &amp; Enteric Virus Acquisition and Immunogenesis Longitudinal (PREVAIL) Cohort study of mother‐infant pairs in Cincinnati, OH assessed whether an epidemiologic association may exist between maternal FUT2 genotype and incidence of acute gastroenteritis (AGE), acute respiratory infection (ARI), and rotavirus vaccine shedding in their infants. We expected that the exclusively breastfed children of FUT2+ mothers would have lower incidences of infection due to the unique breastmilk oligosaccharide composition.We included all 75 mother‐infant pairs who exclusively breastfed their infants, which provided a total of 1,243 child‐weeks of follow‐up from birth to 6 months. All mothers were genotyped for FUT2 by PCR. Of these, 40 (53%) infants were vaccinated against rotavirus and had ≥1 weekly stool sample collected within 8 weeks after vaccination and tested by real time RT‐PCR assays to determine vaccine shedding. Infant infection data came from weekly maternal reports of AGE and ARI that were collected by using an automated text messaging system.Infants of FUT2+ mothers were found to have longer duration of rotavirus shedding post‐vaccination than babies of FUT2− mothers (p=0.007). Additionally, infants of FUT2+ mothers had more AGE symptomatic study weeks (5.6%) than children of FUT2− mothers, who had no symptomatic AGE weeks (p&lt;0.001). Similarly, infants of FUT2+ mothers had ARI with fever for approximately 2.7% of study weeks, whereas babies of FUT2− mothers had no cases of ARI with fever (p=0.006). In this ongoing study, we plan to continue our analysis to include the infant’s own FUT2 status and medically‐attended illness.Support or Funding InformationCDC grant number U191P001059, IP‐16‐004

Longitudinal Pattern of First-Phase Insulin Response Is Associated With Genetic Variants Outside the Class II HLA Region in Children With Multiple Autoantibodies.

A declining first-phase insulin response (FPIR) is associated with positivity for multiple islet autoantibodies, irrespective of class II HLA DR-DQ genotype. We examined the associations of FPIR with genetic variants outside the HLA DR-DQ region in the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) study in children with and without multiple autoantibodies. Association between FPIR and class I alleles A*24 and B*39 and eight single nucleotide polymorphisms outside the HLA region were analyzed in 438 children who had one or more FPIR results available after seroconversion. Hierarchical linear mixed models were used to analyze repeated measurements of FPIR. In children with multiple autoantibodies, the change in FPIR over time was significantly different between those with various PTPN2 (rs45450798), FUT2 (rs601338), CTSH (rs3825932), and IKZF4 (rs1701704) genotypes in at least one of the models. In general, children carrying susceptibility alleles for type 1 diabetes experienced a more rapid decline in insulin secretion compared with children without susceptibility alleles. The presence of the class I HLA A*24 allele was also associated with a steeper decline of FPIR over time in children with multiple autoantibodies. Certain genetic variants outside the class II HLA region may have a significant impact on the longitudinal pattern of FPIR.

696 FUT2 Genotype Is Not Associated With Disease Phenotype or Outcomes in Patients With Crohn's Disease

INTRODUCTION: The fucosyltransferase 2 gene (FUT2) is responsible for the regulation of mucosal blood type antigens which can act as receptors for bacterial adhesion and regulate intestinal flora. A homozygous non-sense mutation in this gene leads to the absence of these antigens, termed FUT2 nonsecretor status, and is associated with the development of Crohn's disease (CD). The mechanism of this association is likely via changes in homeostatic symbiosis thus promoting development of inflammation. However, the impact of FUT2 genotype on CD phenotype and outcomes is not known. METHODS: Patients were prospectively enrolled into a single center translational IBD registry. All patients with CD who had available DNA extracted from peripheral blood for genotyping were included. Genotyping was performed using the rs601338-AA SNP, which represents the nonsense mutation (428GA) shown to be causing nonsecretor status. Baseline demographics, disease phenotype, CD-related surgery, and hospitalization were also assessed retrospectively and statistically compared based on FUT2 genotype. RESULTS: 635 patients with CD were studied including 178 wild-type (WT), 314 heterozygous (HET) and 143 homozygous (O) patients. The mean duration of follow up was 8 years 2 months. There were no significant differences detected between genotypes when comparing sex, race, smoking, body-mass index, and age of onset. Presence of extra-intestinal manifestations including arthritis, uveitis, erythema nodosum, pyoderma gangrenosum, and PSC, as well as disease location and behavior were also found to be similar when compared between O vs WT, O vs HET, and O vs HET + WT groups. The mean number of biologics used between groups was 1.50 (O), 1.39 (HET) and 1.42 (WT) (P = 0.55), with no difference in first or total duration of biologic therapy between groups. 60.8% of O patients used immunomodulators compared to 54.8% of HET and 59.6% of WT patients. In addition, there were no differences in the number of patients who required &gt;1 CD-related hospitalization (O = 30.1%, HET = 34.1%, WT = 30.3%) or surgery (O = 32.2%, HET = 39.5%, WT = 32%) with the entire cohort having a mean of 1.46 for hospitalization and 1.43 for surgery, respectively. CONCLUSION: In this single center analysis of 635 patients with Crohn's Disease, FUT2 genotype was not associated with disease phenotype, disease severity, or clinical outcomes. This may be due to the fact that lack of fucosylation is a more of a causative factor but does not contribute to disease progression in CD.

FUT3 and FUT2 genotyping and glycoconjugate profile Lewisb as a protective factor to Toxoplasma gondii infection

The interaction between the ABO, FUT2 and FUT3 genes results in the synthesis of different glycoconjugates profiles expressed in gastrointestinal tract. Moreover, the protozoan Toxoplasma gondii, which causes toxoplasmosis, utilizes this organ as an infection route. We analyzed the frequencies of the different glycoconjugate profiles which were determined by phenotyping ABO and genotyping the status secretor (FUT2; substitution G428A) and Lewis (FUT3; substitution T202C and C314T) histo-blood systems, assessed by PCR-RFLP and PCR-SSP, respectively. A total of 244 pregnant women (G1: Seropositive; G2: Seronegative) for IgG T. gondii antibodies were enrolled. IgG anti-T. gondii antibodies were determined by ELISA. G1 was composed of 158 (64.8%) sample and G2 by 86 (36.2%). The glycoconjugate profile was accessed in 151 seropositive and 85 seronegative samples by the combination of ABO and Lewis phenotyping as well as FUT2 and FUT3 genotyping. In G1, 36 (22.8%) presented the glycoconjugate profile ALeb, 5 (3.3%) A, 13 (8.6) BLeb, 1 (0.6%) B, 41 (27.1%) Leb, 13(8.6%) H, 38(25.2%) Lea and 4 (2.6%) Lec. G2 was composed of 13 (15.3%) of ALeb, 15 (17.6%) BLeb, 1 (1.2%) B, 42 (49,4%) Leb and 14 (16.5) Lea. H and Lec glycoconjugate profiles were not found in G2. The frequencies of the glycoconjugates profiles Leb (p = 0.001) and H (p = 0.005) were significantly different compared between G1 and G2. The glycoconjugate profile H inferred from the ABO phenotyping and FUT3 and FUT2 genotyping is associated with infection by T. gondii in pregnant women and the Leb profile appears to protect the infection by this parasite.

Association of Maternal Secretor Status and Human Milk Oligosaccharides With Milk Microbiota: An Observational Pilot Study.

Breast milk contains several bioactive factors including human milk oligosaccharides (HMOs) and microbes that shape the infant gut microbiota. HMO profile is determined by secretor status; however, their influence on milk microbiota is still uncovered. This study is aimed to determine the impact of the FUT2 genotype on the milk microbiota during the first month of lactation and the association with HMO. Milk microbiota from 25 healthy lactating women was determined by quantitative polymerase chain reaction and 16S gene pyrosequencing. Secretor genotype was obtained by polymerase chain reaction-random fragment length polymorphisms and by HMO identification and quantification. The most abundant bacteria were Staphylococcus and Streptococcus, followed by Enterobacteriaceae-related bacteria. The predominant HMO in secretor milk samples were 2'FL and lacto-N-fucopentaose I, whereas non-secretor milk was characterized by lacto-N-fucopentaose II and lacto-N-difucohexaose II. Differences in microbiota composition and quantity were found depending on secretor/non-secretor status. Lactobacillus spp, Enterococcus spp, and Streptococcus spp were lower in non-secretor than in secretor samples. Bifidobacterium genus and species were less prevalent in non-secretor samples. Despite no differences on diversity and richness, non-secretor samples had lower Actinobacteria and higher relative abundance of Enterobacteriaceae, Lactobacillaceae, and Staphylococcaceae. Maternal secretor status is associated with the human milk microbiota composition and is maintained during the first 4 weeks. Specific associations between milk microbiota, HMO, and secretor status were observed, although the potential biological impact on the neonate remains elusive. Future studies are needed to reveal the early nutrition influence on the reduction of risk of disease.