Noninvasive prenatal diagnosis of Mendelian disorders for consanguineous couples by relative genotype dosage.

Noninvasive prenatal diagnosis relies on the presence in maternal blood of circulating cell-free fetal DNA released by apoptotic trophoblast cells. Widely used for aneuploidy screening, it can also be applied to monogenic diseases (NIPD-M) in case of known parental mutations. Due to the confounding effect of maternal DNA, detection of maternal or biparental mutations requires relative haplotype dosage (RHDO), a method relying on the presence of SNPs that are heterozygous in one parent and homozygous in the other. Unavoidably, there is a risk of test failure by lack of such informative SNPs, an event particularly likely for consanguineous couples who often share common haplotypes in regions of identity-by-descent. Here we present a novel approach, relative genotype dosage (RGDO) that bypasses this predicament by directly assessing fetal genotype with SNPs that are heterozygous in both parents (frequent in regions of identity-by-descent). We show that RGDO is as sensitive as RHDO and that it performs well over a large range of fetal fractions and DNA amounts, thereby opening NIPD-M to most consanguineous couples. We also report examples of couples, consanguineous or not, where combining RGDO and RHDO allowed a diagnosis that would not have been possible with only one approach.

Atypical diabetes with spontaneous remission associated with systemic lupus erythematosus in an adolescent girl of African ancestry, a case report.

BACKGROUND: New-onset diabetes in youth encompasses type 1 diabetes, type 2 diabetes, monogenic diabetes, and rarer subtypes like Type B insulin resistance syndrome and ketosis-prone atypical diabetes in African populations. Some cases defy classification, posing management challenges. Here, we present a case of a unique, reversible diabetes subtype. CASE PRESENTATION: We describe an adolescent African girl recently diagnosed with systemic lupus erythematosus. At age 15, she presented with ketoacidosis, HbA1c of 108.7 mmol/mol (12.1%), and positive anti-insulin antibodies. Initially diagnosed with type 1 diabetes, insulin was prescribed. Due to the presence of obesity and signs of insulin resistance, we added metformin. Concurrently, she received treatment for lupus with hydroxychloroquine, mycophenolate mofetil, and prednisone. After discharge, she stopped insulin due to cultural beliefs. Five months later, her glycemia and HbA1c normalized (37 mmol/mol or 5.5%) without insulin, despite corticosteroid therapy and weight gain. Autoantibodies normalized, and lupus activity decreased. Genetic testing for monogenic diabetes was negative, and the type 1 genetic risk score was exceptionally low. CONCLUSIONS: We present a complex, reversible diabetes subtype. Features suggest an autoimmune origin, possibly influenced by overlapping HLA risk haplotypes with lupus. Lupus treatment or immunomodulation may have impacted diabetes remission. Ancestry-tailored genetic risk scores are currently designed to improve diagnostic accuracy.

Molecular characterization of pathogenic OTOA gene conversions in hearing loss patients.

Bi-allelic loss-of-function variants of OTOA are a well-known cause of moderate-to-severe hearing loss. Whereas non-allelic homologous recombination-mediated deletions of the gene are well known, gene conversions to pseudogene OTOAP1 have been reported in the literature but never fully described nor their pathogenicity assessed. Here, we report two unrelated patients with moderate hearing-loss, who were compound heterozygotes for a converted allele and a deletion of OTOA. The conversions were initially detected through sequencing depths anomalies at the OTOA locus after exome sequencing, then confirmed with long range polymerase chain reactions. Both conversions lead to loss-of-function by introducing a premature stop codon in exon 22 (p.Glu787*). Using genomic alignments and long read nanopore sequencing, we found that the two probands carry stretches of converted DNA of widely different lengths (at least 9 kbp and around 900 bp, respectively).

Bi-allelic loss of ERGIC1 causes relatively mild arthrogryposis.

Arthrogryposis describes the presence of multiple joint-contractures. Clinical severity of this phenotype is variable, and more than 400 causative genes have been proposed. Among these, ERGIC1 is a recently reported candidate encoding a putative transmembrane protein of the ER-Golgi interface. Two homozygous missense variants have been reported in patients with relatively mild non-syndromic arthrogryposis. In a consanguineous family with two affected siblings presenting congenital arthrogryposis and some facial dysmorphism we performed prenatal array-CGH, postnatal targeted exome and genome sequencing. Genome sequencing identified a homozygous 22.6 Kb deletion encompassing the promoter and first exon of ERGIC1. mRNA quantification showed the complete absence of ERGIC1 expression in the two affected siblings and a decrease in heterozygous parents. Our observations validate the pathogenic role of ERGIC1 in congenital arthrogryposis and demonstrate that complete loss of function causes a relatively mild phenotype. These findings will contribute to improve genetic counseling of ERGIC1 mutations.

Immune deficiency, autoimmune disease and intellectual disability: A pleiotropic disorder caused by biallelic variants in the TPP2 gene.

Four individuals from two families presented with a multisystemic condition of suspected genetic origin that was diagnosed only after genome analysis. The main phenotypic features were immune system dysregulation (severe immunodeficiency with autoimmunity) and intellectual disability. The four individuals were found to be homozygous for a 4.4 Kb deletion removing exons 20-23 (NM_003291.4) of the TPP2 gene, predicting a frameshift with premature termination of the protein. The deletion was located on a shared chromosome 13 haplotype indicating a Swiss founder mutation. Tripeptidyl peptidase 2 (TPP2) is a protease involved in HLA/antigen complex processing and amino acid homeostasis. Biallelic variants in TPP2 have been described in 10 individuals with variable features including immune deficiency, autoimmune cytopenias, and intellectual disability or chronic sterile brain inflammation mimicking multiple sclerosis. Our observations further delineate this severe condition not yet included in the OMIM catalog. Timely recognition of TPP2 deficiency is crucial since (1) immune surveillance is needed and hematopoietic stem cell transplantation may be necessary, and (2) for provision of genetic counselling. Additionally, enzyme replacement therapy, as already established for TPP1 deficiency, might be an option in the future.

Exome sequencing identifies a de novo FOXA2 variant in a patient with syndromic diabetes.

OBJECTIVE: When diabetes is associated with congenital malformations, without autoimmune antibodies, a genetic cause is suspected. Here, we aimed to identify a defective gene that led to diabetes. RESEARCH DESIGN AND METHODS: We performed an exome analysis of an index case and his healthy parents. RESULTS: The child presented with childhood-onset diabetes, congenital hypopituitarism, cardiac malformation, and anal atresia. A DNA analysis revealed a heterozygous de novo pathogenic variant in the developmental transcription factor, forkhead box A2 (FOXA2). The mutation resided in the DNA-binding domain, which is highly conserved among species. Tridimensional molecular dynamics simulation modeling predicted an altered interaction between the mutated protein and DNA. CONCLUSIONS: A defect in the FOXA2 DNA-binding domain was associated with childhood-onset diabetes and multiple congenital anomalies, which reflected the pleiotropic nature of the gene. This report extends the recently described phenotype of neonatal hypoglycemia to later-onset diabetes. We suggest to include FOXA2 analysis for neonatal hypoglycemia and to implement a long-term follow-up, particularly for the risk of diabetes.

Novel NEXMIF pathogenic variant in a boy with severe autistic features, intellectual disability, and epilepsy, and his mildly affected mother.

Intellectual disability (ID) and autism spectrum disorders are complex neurodevelopmental disorders occurring among all ethnic and socioeconomic groups. Pathogenic variants in the neurite extension and migration factor (NEXMIF) gene (formerly named KIAA2022) on the X chromosome are responsible for ID, autistic behavior, epilepsy, or dysmorphic features in males. Most affected females described had a milder phenotype or were asymptomatic obligate carriers. We report here for the first time mother-to-son transmission of a novel NEXMIF truncating variant without X-inactivation skewing in the blood. Truncating gene variant leads to symptomatic mother to severely affected son transmission. Our findings emphasize that NEXMIF sequencing should be strongly considered in patients with unexplained autism spectrum disorder, ID, and epilepsy, irrespective of gender. Such testing could increase our knowledge of the pathogenicity of NEXMIF variants and improve genetic counseling.

Circulating tumoral DNA: Preanalytical validation and quality control in a diagnostic laboratory.

We present the results of our technical validation process in establishing the analysis of circulating tumor DNA (ctDNA) as a diagnostic tool. Like most cells in our body, tumor cells shed DNA in the blood flow. Analysis of ctDNA mutational content can provide invaluable information on the genetic makeup of a tumor, and assist oncologists in deciding on therapy, or in following residual disease. However, low absolute amounts of circulating DNA and low tumor fraction constitute formidable analytical challenges. A key step is to avoid contamination with genomic DNA from cell lysis. Several brands of specialized blood collection tubes are available to prevent leukocyte lysis. We show that they are not equally efficient, depending on storage temperature and time before plasma preparation. We report our analysis of preanalytical factors pertaining to ctDNA analysis (tubes, transportation time, temperature) and our conclusions in terms of instructions to prescribing physicians. We also stress the importance of proper DNA quality control and compare several methods, including a differential amplicon length PCR technique which allows determination of multiple QC parameters from minimal amounts of DNA. Altogether, these data provide useful practical information to diagnostic laboratories wishing to implement the assay of ctDNA in clinical practice.

Germline PMS2 and somatic POLE exonuclease mutations cause hypermutability of the leading DNA strand in biallelic mismatch repair deficiency syndrome brain tumours.

Biallelic mismatch repair deficiency (bMMRD) in tumours is frequently associated with somatic mutations in the exonuclease domains of DNA polymerases POLE or POLD1, and results in a characteristic mutational profile. In this article, we describe the genetic basis of ultramutated high-grade brain tumours in the context of bMMRD. We performed exome sequencing of two second-cousin patients from a large consanguineous family of Indian origin with early onset of high-grade glioblastoma and astrocytoma. We identified a germline homozygous nonsense variant, p.R802*, in the PMS2 gene. Additionally, by genome sequencing of these tumours, we found extremely high somatic mutation rates (237/Mb and 123/Mb), as well as somatic mutations in the proofreading domain of POLE polymerase (p.P436H and p.L424V), which replicates the leading DNA strand. Most interestingly, we found, in both cancers, that the vast majority of mutations were consistent with the signature of POLE exo- , i.e. an abundance of C>A and C>T mutations, particularly in special contexts, on the leading strand. We showed that the fraction of mutations under positive selection among mutations in tumour suppressor genes is more than two-fold lower in ultramutated tumours than in other glioblastomas. Genetic analyses enabled the diagnosis of the two consanguineous childhood brain tumours as being due to a combination of PMS2 germline and POLE somatic variants, and confirmed them as bMMRD/POLE exo- disorders. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Mutations in ZMYND10, a gene essential for proper axonemal assembly of inner and outer dynein arms in humans and flies, cause primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is a ciliopathy characterized by airway disease, infertility, and laterality defects, often caused by dual loss of the inner dynein arms (IDAs) and outer dynein arms (ODAs), which power cilia and flagella beating. Using whole-exome and candidate-gene Sanger resequencing in PCD-affected families afflicted with combined IDA and ODA defects, we found that 6/38 (16%) carried biallelic mutations in the conserved zinc-finger gene BLU (ZMYND10). ZMYND10 mutations conferred dynein-arm loss seen at the ultrastructural and immunofluorescence level and complete cilia immotility, except in hypomorphic p.Val16Gly (c.47T>G) homozygote individuals, whose cilia retained a stiff and slowed beat. In mice, Zmynd10 mRNA is restricted to regions containing motile cilia. In a Drosophila model of PCD, Zmynd10 is exclusively expressed in cells with motile cilia: chordotonal sensory neurons and sperm. In these cells, P-element-mediated gene silencing caused IDA and ODA defects, proprioception deficits, and sterility due to immotile sperm. Drosophila Zmynd10 with an equivalent c.47T>G (p.Val16Gly) missense change rescued mutant male sterility less than the wild-type did. Tagged Drosophila ZMYND10 is localized primarily to the cytoplasm, and human ZMYND10 interacts with LRRC6, another cytoplasmically localized protein altered in PCD. Using a fly model of PCD, we conclude that ZMYND10 is a cytoplasmic protein required for IDA and ODA assembly and that its variants cause ciliary dysmotility and PCD with laterality defects.

Diabetes and immune thrombocytopenic purpura: a new association with good response to anti-CD20 therapy.

Type 1 diabetes (T1D) is rarely a component of primary immune dysregulation disorders. We report two cases in which T1D was associated with thrombocytopenia. The first patient, a 13-year-old boy, presented with immune thrombocytopenia (ITP), thyroiditis, and, 3 wk later, T1D. Because of severe thrombocytopenia resistant to immunoglobulins, high-dose steroids, and cyclosporine treatment, anti-cluster of differentiation (CD20) therapy was introduced, with consequent normalization of thrombocytes and weaning off of steroids. Three and 5 months after anti-CD20 therapy, levothyroxin and insulin therapy, respectively, were stopped. Ten months after stopping insulin treatment, normal C-peptide and hemoglobin A1c (HbA1c) levels and markedly reduced anti-glutamic acid decarboxylase (GAD) antibodies were measured. A second anti-CD20 trial for relapse of ITP was initiated 2 yr after the first trial. Anti-GAD antibody levels decreased again, but HbA1c stayed elevated and glucose monitoring showed elevated postprandial glycemia, demanding insulin therapy. To our knowledge, this is the first case in which insulin treatment could be interrupted for 28 months after anti-CD20 treatment. In patient two, thrombocytopenia followed a diagnosis of T1D 6 yr previously. Treatment with anti-CD20 led to normalization of thrombocytes, but no effect on T1D was observed. Concerning the origin of the boys' conditions, several primary immune dysregulation disorders were considered. Thrombocytopenia associated with T1D is unusual and could represent a new entity. The diabetes manifestation in patient one was probably triggered by corticosteroid treatment; regardless, anti-CD20 therapy appeared to be efficacious early in the course of T1D, but not long after the initial diagnosis of T1D, as shown for patient two.

The Effect of ß2-Adrenoceptor Genotype on Phenylephrine Dose Administered During Spinal Anesthesia for Cesarean Delivery.

BACKGROUND: The ß2-adrenoceptor (ADRB2 gene) possesses several polymorphic sites that have physiologic and/or pharmacologic significance. Previous work has demonstrated that the ADRB2 genotype affects the amount of ephedrine administered to maintain blood pressure during cesarean delivery with spinal anesthesia. This study investigated whether the ADRB2 genotype affected phenylephrine dose requirements during cesarean delivery. Our hypothesis was that the ADRB2 genotype altered the ephedrine dose-response and that we would not see this effect if phenylephrine was the vasopressor used to maintain blood pressure because phenylephrine does not act via the ß2-adrenoceptor. METHODS: Women undergoing elective cesarean delivery were studied. Baseline systolic blood pressure (SBP) was determined, and spinal anesthesia was initiated with hyperbaric bupivacaine 12 mg, fentanyl 20 µg, and morphine 200 µg. Hypotension was treated with a phenylephrine infusion using a standardized algorithm (50 µg/min if SBP was 90%-99% of baseline, 100 µg/min for SBP 80%-89% baseline, and 200 µg/min plus boluses for SBP <80% baseline) for 15 minutes after the administration of spinal anesthesia. ADRB2 genotype at codons 16 and 27 was determined. The effect of genotype on administered phenylephrine was compared by analysis of variance and linear regression. RESULTS: Ninety-six women completed the protocol with full data available for analysis. In the unadjusted analysis, there were no significant differences in phenylephrine dose administered among different genotypes at codons 16 and 27. When adjusted for covariates (maternal body mass index, baseline systolic and diastolic blood pressure, neonatal weight, and ethnicity), there was an increase of 200 µg (95% confidence interval, 4-396; P = 0.04) in phenylephrine administered to Arg16 homozygous genotype subjects compared with Gly16 homozygous genotype subjects. CONCLUSIONS: Phenylephrine dose requirements to maintain SBP after spinal anesthesia are affected by ADRB2 genotype but to a lesser extent than ephedrine. This suggests that previous work demonstrating a large effect of ADRB2 genotype on ephedrine dose requirements may be explained, at least in part, by a differential response to ephedrine based on ADRB2 genotype. It also suggests that there may be ADRB2-mediated differences in the physiologic response to spinal anesthesia.

Recurrent spontaneous pneumothorax in an NF1 patient with a novel causative variant: broadening genotype-phenotype correlations.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease with complete penetrance, most commonly known to affect the skin and eyes. Although lung involvement in the form of cysts and bullae occurs in up to 20% of adults, the seemingly intuitive association of NF1 and spontaneous pneumothorax is not widely recognised among clinicians. Here, we report the second case of recurring spontaneous pneumothorax in the context of NF1 with a confirmed molecular diagnosis. In both cases, the NF1 variants featured a premature stop codon in the C-terminal protein domain. Interestingly, our patient had mild skin symptoms, suggesting that spontaneous pneumothorax may not be correlated with cutaneous disease severity. More genotype-phenotype correlation studies are needed for NF1 in general and for its link to spontaneous pneumothorax in particular.

Enhancing fetal outcomes in GCK-MODY pregnancies: a precision medicine approach via non-invasive prenatal GCK mutation detection.

Background: Mutations in the GCK gene cause Maturity Onset Diabetes of the Young (GCK-MODY) by impairing glucose-sensing in pancreatic beta cells. During pregnancy, managing this type of diabetes varies based on fetal genotype. Fetuses carrying a GCK mutation can derive benefit from moderate maternal hyperglycemia, stimulating insulin secretion in fetal islets, whereas this may cause macrosomia in wild-type fetuses. Modulating maternal glycemia can thus be viewed as a form of personalized prenatal therapy, highly beneficial but not justifying the risk of invasive testing. We therefore developed a monogenic non-invasive prenatal diagnostic (NIPD-M) test to reliably detect the transmission of a known maternal GCK mutation to the fetus. Methods: A small amount of fetal circulating cell-free DNA is present in maternal plasma but cannot be distinguished from maternal cell-free DNA. Determining transmission of a maternal mutation to the fetus thus implies sequencing adjacent polymorphisms to determine the balance of maternal haplotypes, the transmitted haplotype being over-represented in maternal plasma. Results: Here we present a series of such tests in which fetal genotype was successfully determined and show that it can be used to guide therapeutic decisions during pregnancy and improve the outcome for the offspring. We discuss several potential hurdles inherent to the technique, and strategies to overcome these. Conclusion: Our NIPD-M test allows reliable determination of the presence of a maternal GCK mutation in the fetus, thereby allowing personalized in utero therapy by modulating maternal glycemia, without incurring the risk of miscarriage inherent to invasive testing.

The effect of OPRM1 and COMT genotypes on the analgesic response to intravenous fentanyl labor analgesia.

BACKGROUND: IV fentanyl is used as a labor analgesic; however, few studies have reported the effects of IV fentanyl for early labor analgesia. We evaluated the analgesic response to IV fentanyl according to the combined effect of the single-nucleotide polymorphisms rs1799971 (c.118A/G, p. 40Asn/Asp) of the µ-opioid receptor gene (OPRM1) and rs4680 (c.472G/A, p.158Val/Met) of the catechol-O-methyltransferase (COMT) gene in women requesting labor analgesia. METHODS: Labor analgesia was initiated with IV fentanyl 1.5 µg/kg. The primary outcome was analgesic success, defined as Numerical Verbal Pain Scale score≤10/100 15 minutes after the dose of fentanyl. Analgesic and side effect outcomes were compared according to OPRM1 and COMT genotypes. RESULTS: One hundred six women were enrolled and received IV fentanyl. IV analgesic success was 6% in women with the combination Asn/Asn-Met/Met (n=17) versus 20% in all other women combined (not Asn/Asn-Met/Met; P=0.30; difference=14%; 95% confidence interval [CI], -10% to 26%). IV analgesic success was 20% in women 118A/A (Asn/Asn) versus 21% for A/G and G/G of OPRM1 (P=0.82; difference=2%; 95% CI, -17% to 19%), and 10% in women 472A (Met/Met) versus 22% for A/G (Met/Val) and G/G (Val/Val) of COMT (P=0.24; difference=12%; 95% CI, -6% to 26%). Met/Met158 (n=31) versus Met/Val or Val/Val of COMT was associated with a smaller decrease in Numerical Verbal Pain Scale (24±18 vs 37±23; P=0.005; mean difference=-13; 99% CI, -25 to -1). CONCLUSION: This study was underpowered to draw firm conclusions on the influence of OPRM1 and COMT genotypes on labor analgesia with IV fentanyl. Further larger studies are needed to evaluate whether genotyping COMT alone or in combination with OPRM1 may have potentially useful clinical implications, such as not offering IV fentanyl in early labor to women who will most likely not benefit from it.

Atypical familial diabetes associated with a novel NEUROD1 nonsense variant.

OBJECTIVES: We aimed to identify the origin of atypical diabetes in a family with four generations of diabetes from South Asia. The family members showed different clinical phenotypes. Members of generation one to three were presumed to have type 2 diabetes and generation four to have type 1 diabetes. CASE PRESENTATION: We performed a genetic analysis of the family using targeted high throughput sequencing. CONCLUSIONS: We identified a novel nonsense variant in the neurogenic differentiation 1 (NEUROD1) gene, co-segregating with diabetes. The variant was located in the DNA-binding domain, altering a protein residue that was very well conserved among different species.

Substitution of arginine 219 by glycine compromises stability, dimerization, and catalytic activity in a G6PD mutant.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common enzymopathies in humans, present in approximately half a billion people worldwide. More than 230 clinically relevant G6PD mutations of different classes have been reported to date. We hereby describe a patient with chronic hemolysis who presents a substitution of arginine by glycine at position 219 in G6PD protein. The variant was never described in an original publication or characterized on a molecular level. In the present study, we provide structural and biochemical evidence for the molecular basis of its pathogenicity. When compared to the wild-type enzyme, the Arg219Gly mutation markedly reduces the catalytic activity by 50-fold while having a negligible effect on substrate binding affinity. The mutation preserves secondary protein structure, but greatly decreases stability at higher temperatures and to trypsin digestion. Size exclusion chromatography elution profiles show monomeric and dimeric forms for the mutant, but only the latter for the wild-type form, suggesting a critical role of arginine 219 in G6PD dimer formation. Our findings have implications in the development of small molecule activators, with the goal of rescuing the phenotype observed in this and possibly other related mutants.

A peripheral signature of Alzheimer's disease featuring microbiota-gut-brain axis markers.

BACKGROUND: Increasing evidence links the gut microbiota (GM) to Alzheimer's disease (AD) but the mechanisms through which gut bacteria influence the brain are still unclear. This study tests the hypothesis that GM and mediators of the microbiota-gut-brain axis (MGBA) are associated with the amyloid cascade in sporadic AD. METHODS: We included 34 patients with cognitive impairment due to AD (CI-AD), 37 patients with cognitive impairment not due to AD (CI-NAD), and 13 cognitively unimpaired persons (CU). We studied the following systems: (1) fecal GM, with 16S rRNA sequencing; (2) a panel of putative MGBA mediators in the blood including immune and endothelial markers as bacterial products (i.e., lipopolysaccharide, LPS), cell adhesion molecules (CAMs) indicative of endothelial dysfunction (VCAM-1, PECAM-1), vascular changes (P-, E-Selectin), and upregulated after infections (NCAM, ICAM-1), as well as pro- (IL1ß, IL6, TNFα, IL18) and anti- (IL10) inflammatory cytokines; (3) the amyloid cascade with amyloid PET, plasma phosphorylated tau (pTau-181, for tau pathology), neurofilament light chain (NfL, for neurodegeneration), and global cognition measured using MMSE and ADAScog. We performed 3-group comparisons of markers in the 3 systems and calculated correlation matrices for the pooled group of CI-AD and CU as well as CI-NAD and CU. Patterns of associations based on Spearman's rho were used to validate the study hypothesis. RESULTS: CI-AD were characterized by (1) higher abundance of Clostridia_UCG-014 and decreased abundance of Moryella and Blautia (p < .04); (2) elevated levels of LPS (p < .03), upregulation of CAMs, Il1ß, IL6, and TNFα, and downregulation of IL10 (p < .05); (3) increased brain amyloid, plasma pTau-181, and NfL (p < 0.004) compared with the other groups. CI-NAD showed (1) higher abundance of [Eubacterium] coprostanoligenes group and Collinsella and decreased abundance of Lachnospiraceae_ND3007_group, [Ruminococcus]_gnavus_group and Oscillibacter (p < .03); (2) upregulation of PECAM-1 and TNFα (p < .03); (4) increased plasma levels of NfL (p < .02) compared with CU. Different GM genera were associated with immune and endothelial markers in both CI-NAD and CI-AD but these mediators were widely related to amyloid cascade markers only in CI-AD. CONCLUSIONS: Specific bacterial genera are associated with immune and endothelial MGBA mediators, and these are associated with amyloid cascade markers in sporadic AD. The physiological mechanisms linking the GM to the amyloid cascade should be further investigated to elucidate their potential therapeutic implications.

Static respiratory cilia associated with mutations in Dnahc11/DNAH11: a mouse model of PCD.

Primary ciliary dyskinesia (PCD) is an inherited disorder causing significant upper and lower respiratory tract morbidity and impaired fertility. Half of PCD patients show abnormal situs. Human disease loci have been identified but a mouse model without additional deleterious defects is elusive. The inversus viscerum mouse, mutated at the outer arm dynein heavy chain 11 locus (Dnahc11) is a known model of heterotaxy. We demonstrated immotile tracheal cilia with normal ultrastructure and reduced sperm motility in the Dnahc11(iv) mouse. This is accompanied by gross rhinitis, sinusitis, and otitis media, all indicators of human PCD. Strikingly, age-related progression of the disease is evident. The Dnahc11(iv) mouse is robust, lacks secondary defects, and requires no intervention to precipitate the phenotype. Together these findings show the Dnahc11(iv) mouse to be an excellent model of many aspects of human PCD. Mutation of the homologous human locus has previously been associated with hyperkinetic tracheal cilia in PCD. Two PCD patients with normal ciliary ultrastructure, one with immotile and one with hyperkinetic cilia were found to carry DNAH11 mutations. Three novel DNAH11 mutations were detected indicating that this gene should be investigated in patients with normal ciliary ultrastructure and static, as well as hyperkinetic cilia.

Rapid detection of genetic variants in hypertrophic cardiomyopathy by custom DNA resequencing array in clinical practice.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease (1/500) and the most common cause of sudden cardiac death in young people. Pathogenic mutation detection of HCM is having a growing impact on the medical management of patients and their families. However, the remarkable genetic and allelic heterogeneity makes molecular analysis by conventional methods very time-consuming, expensive and difficult to realise in a routine diagnostic molecular laboratory. METHOD AND RESULTS: The authors used their custom DNA resequencing array which interrogates all possible single-nucleotide variants on both strands of all exons (n=160), splice sites and 5'-untranslated region of 12 HCM genes (27 000 nucleotides). The results for 122 unrelated patients with HCM are presented. Thirty-three known or novel potentially pathogenic heterozygous single-nucleotide variants were identified in 38 patients (31%) in genes MYH7, MYBPC3, TNNT2, TNNI3, TPM1, MYL3 and ACTC1. CONCLUSIONS: Although next-generation sequencing will replace all large-scale sequencing platforms for inherited cardiac disorders in the near future, this HCM resequencing array is currently the most rapid, cost-effective and reasonably efficient technology for first-tier mutation screening of HCM in clinical practice. Because of its design, the array is also an appropriate tool for initial screening of other inherited forms of cardiomyopathy.