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Plateau levels of viremia correlate with the degree of CD4+-T-cell loss in simian immunodeficiency virus SIVagm-infected pigtailed macaques: variable pathogenicity of natural SIVagm isolates.

Simian immunodeficiency virus from African green monkeys (SIVagm) results in asymptomatic infection in its natural host species. The virus is not inherently apathogenic, since infection of pigtailed (PT) macaques (Macaca nemestrina) with one isolate of SIVagm results in an immunodeficiency syndrome characterized by progressive CD4+-T-cell depletion and opportunistic infections. This virus was passaged once in a PT macaque and, thus, may not be entirely reflective of the virulence of the parental strain. The goal of the present study was to assess the pathogenicity of the PT-passaged isolate (SIVagm9063) and two primary SIVagm isolates in PT macaques, including the parental strain of the PT-passaged variant. Infection of macaques with any of the three isolates resulted in high levels of primary plasma viremia by 1 week after inoculation. Viremia was quickly controlled following infection with SIVagm155; these animals have maintained CD4+-T-cell subsets and remain healthy. The plateau levels among SIVagm90- and SIVagm9063-inoculated macaques varied widely from 100 to 1 million copies/ml of plasma. Three of four animals from each of these groups progressed to AIDS. Setpoint viremia and the degree of CD4+-T-cell loss at 6 months postinfection were not significantly different between macaques inoculated with SIVagm90 and SIVagm9063. However these parameters were significantly different in SIVagm155-inoculated macaques (P values of <0.01). Considering all the macaques, the degree of CD4+-T-cell loss by 6 months postinfection correlated with the plateau levels of viremia. Thus, similar to SIVsm/mac infection of macaques and human AIDS, viral load is an excellent prognostic indicator of disease course. The inherent pathogenicity of natural SIVagm isolates varies, but such natural isolates are capable of inducing AIDS in macaques without prior macaque passage.

Amino Acid Sequence↗

The bioinformatics approach to identifying pathogenic variants for colorectal cancer (CRC).

Colorectal cancer (CRC) is the third most prevalent cancer globally, accounting for 9.6% of newly diagnosed cases and 9.3% of cancer-related deaths. It develops from the uncontrolled proliferation of glandular cells in the colon and rectum and is categorized into three primary types: sporadic, hereditary, and colitis-associated. While genetic susceptibility is a key factor in CRC pathogenesis, identifying high-impact pathogenic variants remains a significant challenge. This study integrates bioinformatics and population genetics approaches to identify CRC-associated single-nucleotide polymorphisms (SNPs) with potential clinical significance. CRC-associated SNPs were extracted from the Genome-Wide Association Studies (GWAS) Catalog, functionally annotated via HaploReg, and validated via Ensembl. In addition, expression quantitative trait locus (eQTL) data from the GTEx database were used to assess the effects of these variants on gene expression across human tissues. Our analysis identified three high-priority SNPs (rs9379084, rs3184504, and rs11557154) associated with the RREB1, ATXN2, SH2B3, and DCAF12 genes, which exhibited marked allele frequency differences among populations. These findings suggest potential biomarkers for CRC risk assessment and highlight the importance of genetic screening across diverse populations.

Bioinformatics↗

RNU4ATAC-opathy: Clinical, molecular, and transcriptomic insights from a large cohort.

PURPOSE: We aim to better define the genotype and phenotype spectrum of RNU4ATAC-opathy, demonstrate the utility of RNA sequencing (RNA-seq) for variant classification, and highlight the challenges in detecting variants in this noncoding gene. METHODS: Sixty individuals with molecularly confirmed RNU4ATAC-opathy were recruited from multiple clinical and research centers internationally. RNA-seq was available for 7 affected individuals. RESULTS: We report the clinical and molecular findings of 60 individuals, including 42 not previously described, and 33 distinct RNU4ATAC variants, 13 of which are novel. Core features in this cohort-present in most individuals assessed and varying in severity-include microcephaly, short stature, skeletal anomalies, developmental delay, cerebral anomalies, skin conditions, and immune deficiency. Additional findings, such as diabetes, holoprosencephaly, and the absence of various core features in some individuals, highlight the broad phenotypic spectrum. All individuals who underwent RNA-seq showed a consistent pattern of minor intron retention. In 6 individuals, RNA-seq enabled the reclassification of variants of uncertain significance as likely pathogenic. Although RNU4ATAC variants are generally covered by clinical exomes, they are often overlooked in analysis because of their noncoding nature. CONCLUSION: This study highlights the variability of phenotypes and genotypes associated with RNU4ATAC-opathy. Laboratories should ensure RNU4ATAC and other noncoding genes are appropriately assessed by their analysis pipelines.

Lowry-Wood syndrome↗

Linear versus circular mitochondrial genomes: intraspecies variability of mitochondrial genome architecture in Candida parapsilosis.

The yeast species Candida parapsilosis, an opportunistic pathogen, exhibits genetic and genomic heterogeneity. To assess the polymorphism at the level of mitochondrial DNA (mtDNA), the organization of the mitochondrial genome in strains belonging to the three variant groups of this species was investigated. Although these analyses revealed a group-specific restriction fragment pattern of mtDNA, strains belonging to different groups appear to have similar genes in the same gene order. An extensive survey of C. parapsilosis isolates uncovered surprising alterations in the molecular architecture of their mitochondrial genome. A screening strategy for strains harbouring mtDNA with rearranged architecture showed that nearly all strains from groups I and III possess linear mtDNA molecules terminating with arrays of tandem repeat units, while most of the group II strains have a circular mitochondrial genome. In addition, it was found that linear genophores in mitochondria of strains from different groups differ in the sequence of the mitochondrial telomeric repeat unit. The occurrence of altered forms of mtDNA among C. parapsilosis strains opens up the unique possibility to address questions concerning the evolutionary origin and replication strategy of linear and circular genomes in mitochondria.

Candida↗

Phenotypic manifestations and variant reclassification of germline PTEN variants: a nationwide Danish study.

BACKGROUND: Classification of heterozygous germline PTEN variants in patients with, or suspected of having, PTEN hamartoma tumour syndrome (PHTS) remains challenging. Accurate classification is essential as these patients require lifelong cancer surveillance. METHODS: We identified all patients with a PTEN variant previously classified as a variant of uncertain significance (VUS), likely pathogenic (LP) or pathogenic (P), collected clinical data and reclassified all variants using the latest PTEN gene-specific American College of Medical Genetics (ACMG) guidelines. Moreover, genotype-phenotype correlations were assessed. RESULTS: 167 patients from 112 families were enrolled. Eighty-seven unique PTEN variants were identified, including 20 novel variants. After applying the PTEN gene-specific ACMG guidelines, 32 variants (36.8%) were reclassified, resulting in 60 PTEN variants classified as LP/P (69.0%), 18 variants classified as VUS (20.7%), while 9 variants were classified as LB/B (10.3%). Genotype-phenotype correlation was performed among 104 patients with LP/P variants: 51 cancer cases were recorded in 41 patients and a distinct PHTS phenotype was observed in 25% of patients, with macrocephaly being present in 99% of patients with a known head circumference. Twenty-three patients had neurodevelopmental delay and/or autism, and we observed an increased prevalence of missense variants in these patients. CONCLUSION: We identified 87 different PTEN variants, and application of PTEN gene-specific ACMG guidelines led to reclassification of 32 variants (36.8%), underscoring the importance of regular variant reassessment using the most recent gene-specific guidelines, ensuring optimal patient management and surveillance.

Genetic Predisposition to Disease↗

Characterization of the antigenic, immunogenic, and pathogenic variation of infectious bursal disease virus due to propagation in different host systems (bursa, embryo, and cell culture). I. Antigenicity and immunogenicity.

In vitro and in ovo virus neutralization assays were conducted to assess the role of different host systems in infectious bursal disease virus (IBDV) antigenic and immunogenic variation. Four different strains, two variant (1084 E and GLS) and two standard (Edgar and STC), were propagated separately in the bursa of Fabricius and embryos, and were compared with cell culture-adapted preparations of the homologous strains. Chicken polyclonal antisera were prepared against each IBDV and neutralizing antibody titres were determined. Normalized IBDV antibody concentrations were used in neutralization assays against homologous and heterologous IBDVs in 10-day-old specific pathogen free embryos. Both antigenic and immunogenic changes occurred in IBDVs evaluated, as evidenced by differences in the ability of normalized antibody to neutralize IBDV propagated in different host systems. Antibody induced by bursal-derived IBDV neutralized all isolates equally well, whereas antibody induced by cell culture-derived virus neutralized bursal-derived IBDV much less effectively.

Animals↗

FIV infection of IL-2-dependent and -independent feline lymphocyte lines: host cells range distinctions and specific cytokine upregulation.

We have analyzed the ability of three molecular clones of feline immunodeficiency virus (FIV) and an ex vivo variant to infect nine distinct specific-pathogen-free feline cell lines in tissue culture. The purpose of these studies was to elucidate mechanisms by which host cells regulate the level of virus infection and expression and to assess host cell cytokine responses to virus infection. Cells used for the analyzes included four IL-2-dependent continuous T-cell lines (104-C1, 104-C7, MCH5-4 and DB FeTs) which arose from long-term passage, followed by limiting dilution cloning of peripheral blood mononuclear cells (PBMCs); two IL-2-independent T-cell lines (104-C1DL and MCH5-4DL) which originated from two of the IL-2-dependent lines, 104-C1 and MCH5-4; respectively; Crandell feline kidney cells (CrFK); G355-5 brain-derived glial cells; and the T-cell lymphoma line, 3201. Cells were infected with FIV-PPR, FIV-34TF10, FIV 34TF10orf2rep, and a variant arising from FIV-PPR during ex vivo passage on 104-C1DL cells, termed FIV-PPRglial. Infection of the IL-2-dependent T-cell line, 104-C1, by FIV-PPR resulted in the specific and distinct upregulation of cytokine expression. In particular, these cells doubled their expression of the pleiotropic cytokines, interleukin-4 and interleukin-12 after FIV infection. Interferon-gamma production also increased after infection with FIV whereas, TNFalpha expression remained constant. Also, a marked upregulation of MHC class II expression was noted post infection of MCH5-4 and 104-C1 cells with FIV-PPR. Similar results were obtained after infection with FIV-34TF10orf2rep, indicating that the upregulation of cytokine expression is not an isolate-specific phenomenon. Changes in cytokine and class II expression are similar to various reports for the in vivo cytokine alterations in FIV, SIV and HIV infections. The ex vivo infection of these cell lines offers amanipulable system to examine the mechanism(s) by which lentiviruses alter cytokine expression.

Animals↗

Lrrk2 pathogenic substitutions in Parkinson's disease.

Leucine-rich repeat kinase 2 (LRRK2) mutations have been implicated in autosomal dominant parkinsonism, consistent with typical levodopa-responsive Parkinson's disease. The gene maps to chromosome 12q12 and encodes a large, multifunctional protein. To identify novel LRRK2 mutations, we have sequenced 100 affected probands with family history of parkinsonism. Semiquantitative analysis was also performed in all probands to identify LRRK2 genomic multiplication or deletion. In these kindreds, referred from movement disorder clinics in many parts of Europe, Asia, and North America, parkinsonism segregates as an autosomal dominant trait. All 51 exons of the LRRK2 gene were analyzed and the frequency of all novel sequence variants was assessed within controls. The segregation of mutations with disease has been examined in larger, multiplex families. Our study identified 26 coding variants, including 15 nonsynonymous amino acid substitutions of which three affect the same codon (R1441C, R1441G, and R1441H). Seven of these coding changes seem to be pathogenic, as they segregate with disease and were not identified within controls. No multiplications or deletions were identified.

Adult↗

Clinical implications of emerging pathogens in haemophilia: the variant Creutzfeldt-Jakob disease experience.

The impact of variant Creutzfeldt-Jakob disease (vCJD) on the clinical practice of haemophilia in the UK is coloured by the haemophilia community's experience of hepatitis C virus and human immunodeficiency virus (HIV) transmission via plasma-derived therapies in the 1980s, when the delay in recognizing and acting on the potential risks cost many patients their lives and left others to manage another chronic disease. This crisis prompted organisations such as the United Kingdom Haemophilia Centre Doctors' Organisation to advocate for the introduction of haemophilia therapies that would not be susceptible to contamination with blood-borne pathogens. After the identification of vCJD in 1996, a number of public health measures were taken in response to a government-sponsored vCJD risk assessment, and following reports of transfusion-transmission of vCJD, additional guidelines have been developed to prevent person-to-person transmission, some of which may impact the quality and availability of medical and surgical care. Variant CJD has had a significant negative effect on the UK haemophilia community, shaking patient confidence in the therapies they have received over the last 21 years, affecting the quality of care and creating the risk of stigmatizing the community as it was in the 1980s. As with HIV and vCJD, emerging blood-borne infectious agents will likely affect blood and blood-derived therapies well before we become aware of its presence. As a result, only therapies with the lowest level of risk should be used for care of patients with haemophilia.

Animals↗

Inherited thrombophilic disorders in young adults with ischemic stroke and patent foramen ovale.

BACKGROUND AND PURPOSE: The pathogenic link between patent foramen ovale (PFO) and stroke remains unknown in most cases. We investigated the association between inherited thrombophilic disorders and PFO-related strokes in a series of young adults in the setting of a case-control study. METHODS: We investigated 125 consecutive subjects (age, 34.7+/-7.3 years) with ischemic stroke and 149 age- and sex-matched control subjects. PFO was assessed in all patients with transcranial Doppler sonography with intravenous injection of agitated saline according to a standardized protocol. Genetic analyses for the factor V (FV)(G1691A) mutation, the prothrombin (PT)(G20210A) variant, and the TT677 genotype of methylenetetrahydrofolate reductase (MTHFR) were performed in all subjects. RESULTS: A pathogenic role of PFO was presumed in 36 patients (PFO+). Interatrial right-to-left shunt either was not detected or was considered unrelated to stroke occurrence in the remaining 89 patients (PFO-). The PT(G20210A) variant was more frequent in the PFO+ group compared with control subjects and the PFO- group (PFO+ versus control subjects, 11% versus 2%; 95% CI, 0.04 to 0.94; PFO+ versus PFO-, 11% versus 1.1%; 95% CI, 1.09 to 109; P=0.047). A similar distribution was observed for subjects carrying either the PT(G20210A) variant or the FV(G1691A) mutation (PFO+ versus control subjects, 19.4% versus 5.3%; 95% CI, 0.08 to 0.75; PFO+ versus PFO-, 19.4% versus 3.3%; 95% CI, 1.45 to 26.1; P=0.021). Combined thrombophilic defects were observed in 3 subjects of the PFO+ group, in 2 control subjects (8.3% versus 1.3%; 95% CI, 0.01 to 0.66; P=0.015), and in 0 subjects in the PFO- group. A trend toward a difference in the frequency of the FV(G1691A) mutation between PFO+ and control subjects was found after bivariate analysis (11% versus 3.3%; P=0.068) but not after multinomial logistic regression analysis. No significant association was found in the distribution of the TT MTHFR genotype in the 3 groups. CONCLUSIONS: In young adults, the PT(G20210A) variant and, to a lesser extent, the FV(G1691A) mutation may represent risk factors for PFO-related cerebral infarcts. A role of systemic thrombophilic disorders in the pathogenesis of this specific subtype of stroke may be hypothesized.

Adult↗

Familial lymphoma and genetic predisposition: an updated review.

BACKGROUND: Several factors contribute to the development of malignant lymphomas including environmental exposures, bacterial and viral infections, as well as familial and genetic factors. MAIN BODY: Numerous somatic variants are involved in lymphomagenesis, and an increasing number of germline variants predisposing patients to lymphoid neoplasm have been identified. Although most lymphomas arise sporadically, epidemiological studies have linked a familial history of lymphomas and other hematological tumors with an increased lymphoma risk. Although rare, familial clustering of malignant lymphoma is well documented, and the constellations suggest inherited risk factors. Recent technological advancements have improved our ability to identify genetic factors associated with lymphoma that overall lead to a better understanding of genetic susceptibility for these entities. In this context, we here provide a comprehensive perspective on lymphoma risk factors to support improved lymphoma risk assessment and testing. A dedicated clinical management could influence future advances in lymphoma therapies and might also prevent severe toxicity and secondary malignancies. However, to date, only few susceptibility genes for malignant lymphomas have been identified. Highly penetrant mutations in known genes cannot account for most of the excess in a polygenic and heterogenic disease such as cancer. High-throughput sequencing identifies pathogenic variants that may constitute most low-penetrance alleles. However, their detection requires many well-characterized cases and controls. In this review, we therefore also include a short discussion on a Swiss cohort where we prospectively collect and samples for genetic data from individuals with a family history of lymphoma. We are convinced that such an approach is more informative and feasible than a population-based project with unselected cases and aim to better inform both genetic counsellors and oncologists. CONCLUSION: Inherited genetic factors contribute to lymphoma risk in a subset of patients. Improved identification of susceptibility variants, particularly through family-based studies, may enhance risk assessment and inform personalized clinical management.

Humans↗

Immunological variants of the aerobactin-cloacin DF13 outer membrane protein receptor IutA among enteric bacteria.

Mouse monoclonal antibodies (MAbs) were generated against a 76-kDa IutA receptor of pathogenic avian Escherichia coli 15972. Six of the eight IutA-specific MAbs isolated (AB1 to AB6) were shown to be directed toward membrane-exposed conformational epitopes, although they did not interfere with the uptake of ferric aerobactin and cloacin DF13 as assessed by competition experiments with purified ligands. The two remaining IutA MAbs (AB9 and AB10) recognized linear epitopes buried in the IutA molecule. The panel of IutA MAbs was used to characterize IutA variants occurring in strains of E. coli, Klebsiella pneumoniae, Enterobacter spp., and Shigella spp., resulting in the identification of four immunological groups of IutAs. MAb AB9 defined an epitope conserved in all IutA variants. In addition, the panel of IutA MAbs served to identify the presence of IutA in wild-type bacteria grown in the presence of diphenylamine to reduce the expression of O-specific polysaccharide.

Antibodies, Monoclonal↗

A novel PKHD1 missense variant disrupting splicing in a fetus with Caroli disease.

BACKGROUND: Caroli disease (CD) is a rare inherited disorder characterized by dilatation of intrahepatic bile ducts, and prenatal diagnosis of this disease is extremely rare. PKHD1 is the only known causative gene, yet the pathogenicity of most missense variants remains unclear. METHODS: Exome sequencing (ES) was performed on a fetus with clinical features of CD. Candidate variants were validated by Sanger sequencing in the family. The impact of the novel missense variant on pre-mRNA splicing was assessed using minigene assays, and structural modeling of the PKHD1 protein was conducted with AlphaFold 3. RESULTS: At 23 weeks of gestation, the fetus showed hepatic cysts on ultrasound and a "central dot" sign on MRI, suggesting a diagnosis of CD. The fetus also exhibited features of autosomal recessive polycystic kidney disease and oligohydramnios. ES identified and Sanger sequencing confirmed three PKHD1 variants: a paternal nonsense variant c.5323C>T; p.(Arg1775*), and two maternal missense variants c.6682G>C; p.(Glu2228Gln) and c.8012G>T; p.(Arg2671Leu). The variant c.6682G>C is novel and minigene assays demonstrated that it caused exon 40 skipping, leading to an in&#x2011;frame deletion (c.6491_6682del; p.(Gly2164_Arg2227del)). Structural modeling predicts that this deletion lies within a large &#x3b2;&#x2011;barrel domain and may compromise its structural stability. Conclusion We characterize a novel missense variant that causes aberrant splicing of PKHD1 in CD. This finding underscores the necessity of functional analysis for evaluating the pathogenicity of missense variants, especially those at the last nucleotide of an exon. Our study expands the mutation spectrum of PKHD1 and provides insights into genotype&#x2011;phenotype correlations.

Humans↗

Assessment the carrier frequency of monogenic diseases in populations requiring assisted reproductive technology.

PURPOSE: The objective of this study is to assess the carrier frequency and pathogenic variation of monogenetic diseases in a population of 114 subjects in Han Chinese from Hebei province who are undergoing assisted reproductive technology through the utilization of Expanded Carrier Screening (ECS). METHODS: The study utilized a panel consisting of 155 severe monogenic recessive genetic diseases for ECS. Next-generation sequencing technology was employed to identify specific variants associated with ECS in a cohort of 114 subjects from 97 couples, comprising 97 females and 17 male spouses. RESULTS: A total of 114 individuals received ECS. The carrier rate of pathogenic genes in the enrolled population was 44.74% (51/114). Among the 97 females, the carrier rate of pathogenic genes was higher in those without assisted reproduction indicators than in those with assisted reproduction indicators (59.09% vs. 41.33%). However, the carrier rate of pathogenic genes in males without assisted reproductive technology was slightly lower than that with assisted reproductive technology (40% vs. 41.67%). Among both female and male participants, the carrier rate of pathogenic genes between individuals without indicators of assisted reproduction and those with such indicators was 55.55% vs. 41.38%. In 51 carriers, 72.55% (37/51) carried one genetic variant, 25.49% (13/51) carried two genetic variants, and 1.96% (1/51) carried three genetic variants. A total of 38 pathogenic genes were detected in this study, and GJB2 and MMACHC were most common. The carrier rates of the two genes were both 5.26% (6/114). A total of 55 variations were detected, and c.235delC was most frequently found. The carrier rate was 3.51% (4/114). The incidence of couples carrying the same pathogenic genes was 1.03% (1/97). CONCLUSIONS: The findings elucidate the carrier rate of pathogenic genes among 155 severe monogenic recessive genetic diseases and underscore the significance of ECS as a preventive measure against congenital anomalies. When both partners carry the same genetic mutation for a monogenic disease, preventive strategies can be taken in offspring through preimplantation genetic testing (PGT), prenatal genetic testing, or the utilization of donor gametes. ECS is instrumental in assessing reproductive risk, guiding fertility-related decisions, and reducing the prevalence of monogenic recessive genetic disorders in subsequent generations.

Humans↗

Digenic HNF1A and ABCC8 variants provide mechanistic insight into early-onset diabetes.

CONTEXT: Oligogenic inheritance in maturity-onset diabetes of the young (MODY) remains poorly characterized, and the contribution of multiple candidate variants to disease pathogenesis is incompletely understood. OBJECTIVE: To investigate the pathogenicity and mechanistic contribution of multiple MODY gene variants identified in a MODY-like family and determine their role in early-onset diabetes. METHODS: Comprehensive genetic analysis of known MODY genes was performed in a MODY-like family. Functional effects of HNF1A and HNF1B variants were assessed using luciferase reporter assays in HEK293T cells. Functional characterization of ABCC8 variants included Kir6.2-dependent thallium (Tl+) flux assays, sulfonylurea responsiveness, and channel stability. RESULTS: Four variants in 3 MODY genes were identified in the proband: novel HNF1A p.Ser551Lysfs*2, HNF1B p.Glu102Ala, and ABCC8 p.Arg298Cys and p.Arg521Gln. Functional analysis showed that HNF1A p.Ser551Lysfs*2 retained approximately 5% of wild-type transactivation activity, consistent with loss-of-function, whereas HNF1B p.Glu102Ala and ABCC8 p.Arg521Gln exhibited wild-type-like function. In contrast, ABCC8 p.Arg298Cys reduced channel activity to 77% of wild-type levels while preserving sulfonylurea responsiveness. Segregation analysis identified HNF1A p.Ser551Lysfs*2 and ABCC8 p.Arg298Cys in affected parents. The proband, who inherited both pathogenic variants, developed diabetes earlier than either parent and was exposed to maternal hyperglycemia in utero, which may also have contributed to this early onset. CONCLUSION: Functional characterization distinguishes pathogenic from variants of unknown significance and supports digenic inheritance of HNF1A and ABCC8. Their additive effects, together with intrauterine hyperglycemia, likely accelerated disease onset. This study provides mechanistic evidence for oligogenic contributions to MODY and expands the genetic architecture of early-onset diabetes.

Humans↗

Five genetic markers in the interleukin 1 family in relation to inflammatory bowel disease.

BACKGROUND: An imbalance between the proinflammatory cytokine interleukin 1 beta (IL-1 beta) and the anti-inflammatory cytokine IL-1 receptor antagonist (IL-1ra) has been postulated as a pathogenic factor in inflammatory bowel disease (IBD). AIMS: To study allelic frequencies of novel polymorphisms in the genes for IL-1 beta and IL-1ra in patients with IBD and to assess the relation between ex vivo cytokine production and allelic variants of the IL-1 beta and IL-1ra genes. SUBJECTS: Two hundred and seventy healthy controls, 74 patients with ulcerative colitis (UC), 72 with Crohn's disease (CD), 40 with primary sclerosing cholangitis for the allelic frequencies, and 60 healthy individuals for the ex vivo stimulation test. METHODS: Genotyping was performed by polymerase chain reaction and subsequent cleavage with specific endonucleases (Mwo1, MspAI1, Alu1, Taq1, BsoF1) for five novel restriction fragment length polymorphisms (RFLPs) in the genes for IL-1ra and IL-1 beta. RESULTS: No significant differences were found in the allelic frequencies or allele carriage rates of the markers in the IL-1 beta and IL-1ra genes between CD, UC, and healthy controls. No association between the genetic markers and cytokine production levels was observed. Patients with UC carried the combination of both the infrequent allele of the Taq1 RFLP and the Mwo1 RFLP significantly more frequently (35.2% in UC versus 71.1% in controls). CONCLUSIONS: UC is associated with carriage of both infrequent alleles of the Taq1 and Mwo1 RFLPs. However, it could not be confirmed whether the association reflects a pathogenic mechanism underlying UC.

Adult↗

Detection of the norovirus variants GGII.4 hunter and GGIIb/hilversum in Italian children with gastroenteritis.

Noroviruses (NoVs) are important enteric pathogens of humans. Although they exhibit an impressive genetic diversity, few NoV strains appear to predominate worldwide. Limited epidemiological data are available on NoV gastroenteritis in Italy. In this study, we assessed the prevalence of human NoV in Italian children with gastroenteritis by using a reverse-transcription nested polymerase chain reaction (RT-PCR) assay specific for the RNA-dependent RNA polymerase (RdRp) on faecal samples collected throughout the 2004 surveillance activity in Palermo, Italy. NoVs were detected in 47% of the stool samples obtained from children <5 years age, admitted to hospital with acute non-bacterial gastroenteritis. A selection of strains was further analyzed by partial sequence analysis of the RdRp gene. The strains were characterized as genogroup (GG) II and clustered into two distinct virus populations that resembled the emerging European GGIIb/Hilversum strains and the Australian Hunter GGII.4 strains. A temporal pattern of distribution of the two NoV strains was observed which was consistent with an independent circulation of two separate strains in the local population. Based on this 1-year study we concluded that NoVs were a diffuse cause of sporadic cases of acute childhood gastroenteritis and that strains of global epidemiological relevance were circulating in Palermo, Italy in 2004.

Caliciviridae Infections↗

Increased yield of genetic diagnoses in inherited heart diseases using expanded genome and RNA-splicing analyses.

PURPOSE: The Australian Genomics Cardiovascular Disorders Flagship investigated genome sequencing as a first-line genetic test in 600 individuals with cardiomyopathy, primary arrhythmia syndromes, or congenital heart disease. Analysis of disease-specific virtual gene panels achieved a genetic diagnosis in 38% of participants. We sought to increase genetic diagnosis yields by analyzing lesser-evidenced disease genes, the mitochondrial genome, and by functional analysis of predicted splice-altering variants. METHODS: Genome sequences of 520 participants with cardiomyopathy or primary arrhythmia syndromes were reanalyzed in 572 cardiac genes and the mitochondrial genome. Participants with congenital heart disease were excluded. Variants predicted in silico to disrupt splicing were assessed with blood RNA and minigenes. RESULTS: A new genetic diagnosis was achieved in 4% (19/520) of participants, including deep intronic and mitochondrial genome variants. Ten participants had diagnostic variants in lesser evidenced disease genes; 9 had splicing variant pathogenicity functionally validated. Eleven participants had a newly identified variant of uncertain significance with high suspicion of pathogenicity, warranting clinical review. Our data supported the gene-disease association of 1 new cardiomyopathy gene, TBX20. CONCLUSION: Identifying new gene-disease relationships, maintaining contemporary gene panels, and integrating functional studies to refine splicing variant classifications increase genetic diagnoses for cardiomyopathies and primary arrhythmia syndromes.

Humans↗