Positive Molecular Diagnosis Research Articles

Prevalence of monogenic disease in paediatric patients with a predominant respiratory phenotype

ObjectiveThis study aimed to investigate the prevalence and clinical characteristics of monogenic disease in paediatric patients with a predominant respiratory phenotype.MethodsExome sequencing was performed in a cohort of 971 children...

MO962EPIDEMIOLOGY AND CLINICAL RELEVANCE OF ACUTE KIDNEY INJURY IN KIDNEY TRANSPLANT RECIPIENTS

Background and AimsVery few information about COVID-19 in kidney transplant recipients (KTRs) are known and the available evidence are based on limited case series. In KTRs, Acute Kidney Injury (AKI) of different causes is known to be associated with a decreased graft survival: direct viral infection and local inflammation may potentially lead to a premature loss of graft function and to an increased risk of death in COVID-19 patients.To evaluate prevalence, stage, causes of AKI and mortality in KTRs with a positive pharyngeal swab for SARS-CoV-2 in our transplant center located in a 500-bed University Hospital.MethodIn March-June 2020, we evaluated in 25 COVID-19 KTRs demographic and transplant characteristics, comorbidities, immunosuppressive therapies (IT). Patients were screened for type of symptoms, management of IT, complications and outcome. AKI was graded according to 2012 KDIGO guidelines and causes were investigated basing on both clinical and laboratory variables. AKI prevalence in KTRs was compared to that observed in the whole hospitalized COVID-19 patients.ResultsDuring the first wave of pandemic, a total of 945 patients were admitted to our hospital with a reported AKI prevalence of 37%. AKI classified using 2012 KDIGO guidelines associated with an increased mortality risk in the whole population.In this setting, we observed that 25 KTRs followed-up in our University Hospital had a positive molecular diagnosis for COVID-19: median age was 58 years and 80% were males. Considering the most frequent comorbidities, 100% of KTRs had hypertension and 7/25 (29%) had diabetes. Clinical symptoms at enrollment were fever (95%), cough (47%), dyspnea (30%). Regarding IT, 100% of patients were taking CNI, 64% antimetabolite agents and 76% steroids. Of note, 19/25 patients (76%) were hospitalized and 6/19 (31.5%) were admitted to Intensive Care Unit (ICU). Mean length of hospital stay was 23 days. At admission, all KTRs stopped MMF and increased steroid doses, concomitantly decreasing CNI levels.AKI occurred in 60% of KTRs (12/25), AKI KDIGO grading as follow: stage 1 4/12 (33.3%), stage 2 3/12 (25%), stage 3 5/12 (41.7%); development favored by low eGFR/increased serum creatinine (mean serum creatinine 2.06 mg/dl): 4/25 (16%) required hemodialysis and the most frequent cause of AKI was sepsis or septic shock. Overall mortality in KTRs was 37,5% (9/25): of note, 88% (8/9) of patients with a worse outcome had developed AKI.ConclusionAKI prevalence was significantly higher in KTRs than in non-transplanted COVID-19 patients. AKI development was associated with an increased risk of mortality: of note, mortality rate in KTRs was significantly higher than that observed in the non-transplanted patients. COVID-19 lead to a difficult management of IT, in particular for elevated tacrolimus levels due to associated antiviral and antibiotic therapies. COVID-19-associated AKI in KTRs may lead to an increased risk of rejection and premature loss of graft function with the need of skilled nephrological follow-up.

Real-World Effectiveness of the mRNA-1273 Vaccine Against COVID-19: Interim Results from a Prospective Observational Cohort Study

Background: Phase 3 trials found mRNA-1273 was highly effective in preventing COVID-19. We conducted a prospective cohort study at Kaiser Permanente Southern California (KPSC) to determine the real-world vaccine effectiveness (VE) of mRNA-1273 in preventing COVID-19 diagnosis and severe disease.Methods: For this planned interim analysis, individuals aged ≥18 years receiving 2 doses of mRNA-1273 ≥24 days apart (12/18/2020-3/31/2021) were 1:1 matched with randomly selected unvaccinated individuals on age, sex, and race/ethnicity, with follow-up through 6/30/2021. Outcomes were COVID-19 diagnosis (SARS-CoV-2 positive molecular test or COVID-19 diagnosis code) or severe disease (COVID-19 hospitalization and COVID-19 hospital death). Adjusted hazard ratios (aHR) and confidence intervals (CI) were estimated by Cox proportional hazards models accounting for multiple comparisons. Adjusted VE was calculated as (1-aHR)x100. Whole genome sequencing was performed on SARS-CoV-2 positive specimens.Findings: This analysis included 352,878 recipients of 2 doses of mRNA-1273 matched to 352,878 unvaccinated individuals. VE (99·3% CI) against COVID-19 diagnosis was 87·4% (84·8-89·6%). VE against COVID-19 hospitalization and hospital death was 95·8% (90·7-98·1%) and 97·9% (66·9-99·9%), respectively. VE was higher against symptomatic (88·3% [98·3% CI: 86·1%-90·2%]) than asymptomatic COVID-19 (72·7% [53·4%-84·0%]), but was generally similar across age, sex, and racial/ethnic subgroups. VE among individuals with history of COVID-19 ranged from 8·2-33·6%. The most prevalent variants were Delta (47·1%), Alpha (21·4%), Gamma (11·4%), Epsilon (4·3%), and Iota (4·3%) among fully vaccinated individuals and Alpha (41·2%), Epsilon (18·2%), Delta (11·0%) and Gamma (8·6%) among unvaccinated individuals.Interpretation: These interim results provide reassuring evidence of the VE of 2 doses of mRNA-1273 across age, sex, and racial/ethnic subgroups, and against asymptomatic and symptomatic COVID-19, and severe COVID-19 outcomes. Among individuals with history of COVID-19, mRNA-1273 vaccination may offer added protection beyond immunity acquired from prior infection. Longer follow-up is needed to fully evaluate VE of mRNA-1273 against emerging SARS-CoV-2 variants.Funding: Moderna Inc.Declaration of Interests: KJB, LSS, LQ, BKA, YL, GSL, YT, AF, HST, JET, HFT are employees of Kaiser Permanente Southern California, which has been contracted by Moderna for the conduct of this present study. CAT is an employee of and a shareholder in Moderna Inc. KJB received funding from GlaxoSmithKline, Dynavax, Pfizer, Gilead, and Seqirus unrelated to this manuscript. LSS received funding from GlaxoSmithKline, Dynavax, and Seqirus unrelated to this manuscript. LQ received funding from GlaxoSmithKline and Dynavax unrelated to this manuscript. BKA received funding from GlaxoSmithKline, Dynavax, Seqirus and Pfizer unrelated to this manuscript. YL received funding from GlaxoSmithKline, Dynavax, Seqirus and Pfizer unrelated to this manuscript. GSL received funding from GlaxoSmithKline unrelated to this manuscript. YT received funding from GlaxoSmithKline unrelated to this manuscript. AF received funding from Pfizer, GlaxoSmithKline, CDC, and Gilead unrelated to this manuscript. HST received funding from GlaxoSmithKline, Pfizer, ALK, and Wellcome unrelated to this manuscript. JET received funding from Pfizer unrelated to this manuscript. HFT received funding from GlaxoSmithKline and Seqirus unrelated to this manuscript; HFT also served in advisory boards for Janssen and Pfizer.Ethics Approval Statement: The KPSC Institutional Review Board provided ethical approval for the study.

Molecular Diagnoses of X-Linked and Other Genetic Hypophosphatemias: Results From a Sponsored Genetic Testing Program.

ABSTRACTX‐linked hypophosphatemia (XLH), a dominant disorder caused by pathogenic variants in the PHEX gene, affects both sexes of all ages and results in elevated serum fibroblast growth factor 23 (FGF23) and below‐normal serum phosphate. In XLH, rickets, osteomalacia, short stature, and lower limb deformity may be present with muscle pain and/or weakness/fatigue, bone pain, joint pain/stiffness, hearing difficulty, enthesopathy, osteoarthritis, and dental abscesses. Invitae and Ultragenyx collaborated to provide a no‐charge sponsored testing program using a 13‐gene next‐generation sequencing panel to confirm clinical XLH or aid diagnosis of suspected XLH/other genetic hypophosphatemia. Individuals aged ≥6 months with clinical XLH or suspected genetic hypophosphatemia were eligible. Of 831 unrelated individuals tested between February 2019 and June 2020 in this cross‐sectional study, 519 (62.5%) individuals had a pathogenic or likely pathogenic variant in PHEX (PHEX‐positive). Among the 312 PHEX‐negative individuals, 38 received molecular diagnoses in other genes, including ALPL, CYP27B1, ENPP1, and FGF23; the remaining 274 did not have a molecular diagnosis. Among 319 patients with a provider‐reported clinical diagnosis of XLH, 88.7% (n = 283) had a reportable PHEX variant; 81.5% (n = 260) were PHEX‐positive. The most common variant among PHEX‐positive individuals was an allele with both the gain of exons 13–15 and c.*231A>G (3′UTR variant) (n = 66/519). Importantly, over 80% of copy number variants would have been missed by traditional microarray analysis. A positive molecular diagnosis in 41 probands (4.9%; 29 PHEX positive, 12 non‐PHEX positive) resulted in at least one family member receiving family testing. Additional clinical or family member information resulted in variant(s) of uncertain significance (VUS) reclassification to pathogenic/likely pathogenic (P/LP) in 48 individuals, highlighting the importance of segregation and clinical data. In one of the largest XLH genetic studies to date, 65 novel PHEX variants were identified and a high XLH diagnostic yield demonstrated broad insight into the genetic basis of XLH. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Application of Next-Generation Sequencing for Genetic Diagnosis in Neonatal Intensive Care Units: Results of a Multicenter Study in China.

To identify next-generation-sequencing (NGS) clinical usability and to propose a standard diagnostic routine for critically ill infants, aged less than 100 days and suspected of having a genetically heterogeneous condition, a retrospective study was conducted between January 2016 and December 2018 at neonatal intensive care units (NICUs) of three tertiary hospitals in Shanghai, China. Whole-exome sequencing (WES) or panel sequencing was performed on 307 patients. Trio-WES, trio-panel, proband-WES, and proband-panel diagnostic yields were 39.71% (83/209), 68.75% (22/32), 59.09% (26/44), and 33.33% (4/12), respectively. Definitive molecular diagnoses of 142 infants (46.25%) uncovered 99 disorders; 21 disorders displayed on 44.37% of the diagnosed patients. Genetic etiologies were identified for 61.73% (50/81) of the deceased infants. One in three (29.58%) diagnosed infants exhibited one of the following four clinical traits which had a higher odds of diagnostic rate: integument abnormality (adjusted odds ratio [aOR], 19.7; 95% confidence interval [CI], 2.5–156.3), complex immune-related phenotypes (aOR, 9.2; 95% CI, 1.4–83.5), mixed nervous system phenotypes and congenital anomalies (aOR, 5.0; 95% CI, 1.3–19.1), or mixed metabolism and nervous system phenotypes (aOR, 4.5; 95% CI, 1.0–21.5). Our results demonstrated that NGS was an effective diagnostic tool. Infants exhibiting integument, complex immune-related conditions, metabolism, and nervous signs have higher chances of carrying variants in known disease-causing genes. The number of specific phenotypes could be used as an independent predictor of a positive molecular diagnosis, rather than an isolated abnormality. We developed a molecular diagnostic procedure for the use of NGS for diagnosis in Chinese NICU population based on individual characteristics.

Underexpression of circulating miR-145-5p and miR-133a-3p are associated with breast cancer and immunohistochemical markers.

MicroRNAs (miRNAs) are involved in the regulation of genes with important roles in cancer. Therefore, they represent interesting targets as biomarkers for early detection, follow-up, and prognosis of the disease. In early stages of breast cancer, differences in the expression of miR-148b-3p, miR-145-5p and miR-133a-3p have been reported. To compare the expression of miR-148b-3p, miR-145-5p and miR-133a-3p in serum samples from female patients with and without breast cancer. Case control study. We quantified the expression by real-time polymerase chain reaction of miR-148b-3p, miR-145-5p, and miR-133a-3p in serum samples from 27 breast cancer (BC) and 17 benign breast tumor patients. Comparison between groups with categorical variables was made using the Pearson's Chi-square test. Comparative analysis for continuous variables between two groups was performed using the Student's t-test. One-way analysis of variance (ANOVA) was used for multigroup comparison, followed by Tukey HSD analysis. The use of contraceptives and a high number of births were identified as risk factors for BC. We observed that miR-145-5p expresses in low levels in BC and positively diagnosed Her2 patients. In addition, BC patients with either ductal carcinoma or positive molecular diagnosis for estrogen receptor, progesterone receptor, luminal A, or Her2 negative, presented a decreased expression of miR-133a-3p. We observed an existing association between the molecular characteristics of BC and levels of circulating miR-133a-3p and miR-145-5p, proving the potential role of miRNAs as biomarkers for BC.

Comprehensive genetic testing of Chinese SNHL patients and variants interpretation using ACMG guidelines and ethnically matched normal controls

Hereditary hearing loss is a monogenic disease with high genetic heterogeneity. Variants in more than 100 deafness genes underlie the basis of its pathogenesis. The aim of this study was to assess the ratio of SNVs in known deafness genes contributing to the etiology of both sporadic and familial sensorineural hearing loss patients from China. DNA samples from 1127 individuals, including normal hearing controls (n = 616), sporadic SNHL patients (n = 433), and deaf individuals (n = 78) from 30 hearing loss pedigrees were collected. The NGS tests included analysis of sequence alterations in 129 genes. The variants were interpreted according to the ACMG/AMP guidelines for genetic hearing loss combined with NGS data from 616 ethnically matched normal hearing adult controls. We identified a positive molecular diagnosis in 226 patients with sporadic SNHL (52.19%) and in patients from 17 deafness pedigrees (56.67%). Ethnically matched MAF filtering reduced the variants of unknown significance by 8.7%, from 6216 to 5675. Some complexities that may restrict causative variant identification are discussed. This report highlight the clinical utility of NGS panels identifying disease-causing variants for the diagnosis of hearing loss and underlines the importance of a broad data of control and ACMG/AMP standards for accurate clinical delineation of VUS variants.

Microbiological, molecular, and histopathological findings in goats experimentally infected with Actinobacillus seminis

The objective of this study was to experimentally evaluate the pathogenicity of an Actinobacillus seminis isolate named SAAS01 in goats. Animals were challenged with 2 mL of a suspension containing 1,5 × 108 CFU/mL of A. seminis (SAAS01 isolate) through the intrapreputial, epididymis tail, and conjunctival routes. Epididymis and testicular fragments were submitted to histopathological exam, and semen samples underwent microbiological and molecular diagnoses. Clinically, a unilateral increase in firm consistency was observed in the epididymis and testicles of two animals inoculated in epididymis tail and in one animal inoculated through conjunctival sac; this firmness continued until the day of euthanasia. Two goats inoculated through epididymis tail and conjunctival sac routes presented histopathological findings with macroscopically and microscopically significant changes. A. seminis was isolated from semen samples collected from goats inoculated through the epididymis tail and conjunctival sac routes. A. seminis DNA was amplified from six semen samples of three goats inoculated through the epididymis tail, two in conjunctival sac and one through intrapreputial route. The experimental infection model using goats confirmed the pathogenicity of the A. seminis isolate, demonstrating the predilection of the agent for the epididymis, with clinical signs, histopathological lesions, bacterial isolation, and a positive molecular diagnosis.

Neuron-specific enolase as biomarker for possible neuronal damage in dogs with distemper vírus

ABSTRACT: Neuron-specific enolase (NSE) is a biomarker of neuronal cell lysis, which demonstrates stability in extracellular fluids such as blood and cerebrospinal fluid. To the authors knowledge there is no research information comparing the use of NSE in dogs with and without encephalitis, putting in evidence the importance of that biomarker to detect neuronal damage in dogs. The objective was to compare the serum NSE levels in dogs with and without encephalitis, and to determine the serum NSE levels in normal dogs. Thirty eight dogs were evaluated, 19 dogs with encephalitis (EG Group) and 19 dogs without encephalitis (CG Group). The criteria for inclusion in the EG Group were presence of neurological signs in more than one part of the CNS (multifocal syndrome) and positive molecular diagnosis for canine distemper virus; for the CG Group were an age between 1 to 7 years and be clinically normal; NSE were measured in serum using an ELISA assay, and the results were compared. In the EG Group the NSE values were higher with significant difference (P=0.0053) when compared with the CG Group. NSE is a biomarker that can be measured in serum samples of dogs to monitor neuronal lesions in encephalitis.

The Features of GGT in Patients with ATP8B1 or ABCB11 Deficiency Improve the Diagnostic Efficiency.

Background and AimsGenetic defects in ATP8B1 or ABCB11 account for the majority of cholestasis with low GGT. But the ranges for GGT in patients with ATP8B1 or ABCB11 deficiency are unclear. This study tried to unravel the features of GGT in these patients that improve diagnostic efficiency.MethodsThis study enrolled 207 patients with chronic cholestasis who were ordered to test for ATP8B1 and/or ABCB11 from January 2012 to December 2015. Additional 17 patients with ATPB81 or ABCB11 deficiency diagnosed between January 2004 and December 2011 were also enrolled in this study. 600 population-matched children served as controls. Clinical data were obtained by retrospectively reviewing medical records.ResultsA total of 26 patients were diagnosed with ATP8B1 deficiency and 30 patients were diagnosed with ABCB11 deficiency. GGT levels were similar between the two disorders at any observed month of age, but varied with age. The peak GGT value was <70U/L in the 2nd~6th month of life, <60U/L in the 7th~12th month and <50U/L beyond one year. GGT levels in patients with a genetic diagnosis were different from that in patients without a genetic diagnosis and controls. Larger ranges for GGT were found in patients without a genetic diagnosis. Some controls had GGT≥70U/L in the 2nd~6th month. Of the 207 patients, 39 (18.8%) obtained a genetic diagnosis. 111 patients met the ranges described above, including all the 39 patients with ATP8B1 or ABCB11 deficiency. The sensitivity was 100.0%. The rate of a positive molecular diagnosis increased to 35.1% (39/111 vs. 39/207, X2 = 10.363, P = 0.001). The remaining 96 patients exceeded the ranges described above and failed to receive a genetic diagnosis. These patients accounted for 43.8% of sequencing cost.ConclusionsGGT levels in patients with ATP8B1 or ABCB11 deficiency varied with age. The peak GGT value was <70U/L in the 2nd~6th month of life, <60U/L in the 7th~12th month and <50U/L beyond one year.

Efficacy of clinical diagnostic criteria for familial hypercholesterolemia genetic testing in Poland

Background and AimsFamilial hypercholesterolemia (FH), which leads to premature cardiovascular events, still remains underrecognized and undertreated in most countries. Untreated FH individuals aged 20–39 years are at 100-fold higher risk of mortality from coronary heart disease compared to those of a general population. Therefore, special efforts should be implemented to diagnose FH patients at early stages of life.The aim of this study was to evaluate the efficacy of the revised Dutch Lipid Clinic Network (DLCN) criteria proposed by the Polish Lipid Experts Forum to select index FH patients for DNA mutational analysis in Poland. MethodsThe study included 193 unrelated adult patients (mean age 48 ± 13 years) with clinical diagnosis of FH based on the revised DLCN score, tested sequentially for mutations in LDLR and APOB genes using bidirectional Sanger sequencing and MLPA techniques. The cut-off points of the clinical FH criteria score were assessed by ROC statistics to identify patients with the highest probability of carrying an FH-causing mutation. ResultsThe causal heterozygous LDLR or APOB mutation was identified in 41% (80/193) of probands. Adults aged <40 years were more likely to carry an FH-causing mutation compared to subjects aged ≥40 years (65% vs. 33%; p < 0.001). LDL-C thresholds for the molecular diagnosis of FH were 5.79 mmol/l for individuals aged<40 and 6.7 mmol/l for subjects ≥40 years old. The threshold values of the clinical diagnostic score for efficient selection of patients for genetic testing were 5 and 7 points for individuals aged <40 and ≥40 years, respectively. ConclusionsThe study validated the efficacy of proposed clinical FH criteria for the disease diagnosis in Poland. The clinical criteria score thresholds for positive FH molecular diagnosis differ depending on age (<40 and ≥40 years). We propose that in the healthcare systems with limited genetic testing resources individuals younger than 40 years, who fulfill the clinical criteria for possible, probable or definite FH should qualify for the FH mutation testing. The index patients aged ≥40 years with clinical diagnosis of probable or definite FH should also qualify for the genetic testing.

Finding the needle in a haystack: identification of cases of Lynch syndrome with MLH1 epimutation.

Constitutional epimutation of the DNA mismatch repair gene, MLH1, represents a minor cause of Lynch syndrome. MLH1 epimutations are characterized by the soma-wide distribution of methylation of a single allele of the MLH1 promoter accompanied by constitutive allelic loss of transcription. 'Primary' MLH1 epimutations, considered pure epigenetic defects, tend to arise de novo in patients without a family history or any apparent genetic mutation. These demonstrate non-Mendelian inheritance. 'Secondary' MLH1 epimutations have a genetic basis and have been linked to non-coding genetic alterations in the vicinity of MLH1. These demonstrate autosomal dominant inheritance. Despite convincing evidence of their role in causing Lynch-type cancers, routine screening for MLH1 epimutations has not been widely adopted. Complicating factors may include: the need to perform additional methylation-based testing beyond the standard genetic screening for a germline mutation; the lack of a consensus algorithm for the selection of patients warranting MLH1 epimutation testing; overlapping molecular pathology features of MLH1 methylation and loss of MLH1 expression with more prevalent sporadic MSI cancers; the rarity of MLH1 epimutation; the variable inter-generational inheritance patterns; and the cost-effectiveness of screening. Nevertheless, a positive molecular diagnosis of MLH1 epimutation is clinically important because carriers have a high personal risk of developing metachronous Lynch-type cancers, and their relatives may also be at risk of carriage. Extending existing universal and clinic-based screening algorithms for Lynch syndrome to include an additional arm of selection criteria for cases warranting MLH1 epimutation testing could provide a cost-effective means of diagnosing these cases.

Molecular Genetic Dissection and Neonatal/Infantile Intrahepatic Cholestasis Using Targeted Next-Generation Sequencing

To ascertain a molecular genetic diagnosis for subjects with neonatal/infantile intrahepatic cholestasis (NIIC) by the use of next-generation sequencing (NGS) and to perform a genotype-phenotype correlation. We recruited Japanese subjects with NIIC who had no definitive molecular genetic diagnosis. We developed a diagnostic custom panel of 18 genes, and the amplicon library was sequenced via NGS. We then compared clinical data between the molecular genetically confirmed subjects with NIIC. We analyzed 109 patients with NIIC ("genetic cholestasis," 31 subjects; "unknown with complications" such as prematurity, 46 subjects; "unknown without complications," 32 subjects), and a molecular genetic diagnosis was made for 28 subjects (26%). The rate of positive molecular genetic diagnosis in each category was 22 of 31 (71%) for the "genetic cholestasis" group, 2 of 46 (4.3%) for the "unknown with complications" group, and 4 of 32 (12.5%) for the "unknown without complications" group. The grouping of the molecular diagnoses in the group with genetic cholestasis was as follows: 12 with Alagille syndrome, 5 with neonatal Dubin-Johnson syndrome, 5 with neonatal intrahepatic cholestasis caused by citrin deficiency, and 6 with progressive familial intrahepatic cholestasis or benign recurrent intrahepatic cholestasis with low gamma-glutamyl transpeptidase levels. Several clinical datasets, including age of onset, direct bilirubin, and aminotransferases, were significantly different between the disorders confirmed using molecular genetic diagnosis. Targeted NGS can be used for molecular genetic diagnosis in subjects with NIIC. Clinical diagnosis should be accordingly redefined in the view of molecular genetic findings.

Clinical predictors of a positive genetic test in hypertrophic cardiomyopathy in the Brazilian population

BackgroundHypertrophic cardiomyopathy is a genetic autosomal dominant disease characterized by left ventricular hypertrophy. The molecular diagnosis is important but still expensive. This work aimed to find clinical predictors of a positive genetic test in a Brazilian tertiary centre cohort of index cases with HCM.MethodsIn the study were included patients with HCM clinical diagnosis. For genotype x phenotype comparison we have evaluated echocardiographic, electrocardiographic, and nuclear magnetic resonance measures. All patients answered a questionnaire about familial history of HCM and/or sudden death. β-myosin heavy chain, myosin binding protein C, and troponin T genes were sequenced for genetic diagnosis.ResultsThe variables related to a higher probability of a positive genetic test were familial history of HCM, higher mean heart frequency, presence of NSVT and lower age. Probabilities of having a positive molecular genetic test were calculated from the final multivariate logistic regression model and were used to identify those with a higher probability of a positive molecular diagnosis.ConclusionsWe developed an easy and fast screening method that takes into account only clinical data that can help to select the patients with a high probability of positive genetic results from molecular sequencing of Brazilian HCM patients.

Monogenic diabetes and the role of the diabetes nurse

Diabetes specialist nurses are ideally placed to identify patients with monogenic diabetes but may lack knowledge of the key features and fail to recognise potential cases. Once the diagnosis of diabetes has been made this may not be revisited and may be assumed to be correct. However, increasing knowledge and awareness of monogenic diabetes will allow health care professionals to question the diagnosis of their patients where appropriate and lead to greater recognition and correct treatment of monogenic diabetes.Maturity onset diabetes of the young (MODY) is typically detected in individuals diagnosed with diabetes before the age of 25 years who also have a parent with diabetes. They are non-insulin dependent but are often mistaken to have type 1 diabetes and are insulin treated. Patients meeting these criteria should be considered for further investigation to ensure their diagnosis is correct. Neonatal diabetes can also be caused by a single genetic change, and patients diagnosed with diabetes within the first six months of life should be referred for genetic testing whatever their current age.This paper highlights three useful means of aiding differential diagnosis: urinary C-peptide creatinine ratio (UCPCR), pancreatic autoantibodies, and use of the online MODY probability calculator. Case studies are used to illustrate the key diagnostic features of MODY and indicate how awareness of family history and other features raised suspicion of an alternative cause of diabetes in these families. Treatment change following a positive molecular genetic diagnosis is also described.

Targeted methylation testing of a patient cohort broadens the epigenetic and clinical description of imprinting disorders

Imprinting disorders are associated with mutations and epimutations affecting imprinted genes, that is those whose expression is restricted by parent of origin. Their diagnosis is challenging for two reasons: firstly, their clinical features, particularly prenatal and postnatal growth disturbance, are heterogeneous and partially overlapping; secondly, their underlying molecular defects include mutation, epimutation, copy number variation, and chromosomal errors, and can be further complicated by somatic mosaicism and multi-locus methylation defects. It is currently unclear to what extent the observed phenotypic heterogeneity reflects the underlying molecular pathophysiology; in particular, the molecular and clinical diversity of multilocus methylation defects remains uncertain. To address these issues we performed comprehensive methylation analysis of imprinted genes in a research cohort of 285 patients with clinical features of imprinting disorders, with or without a positive molecular diagnosis. 20 of 91 patients (22%) with diagnosed epimutations had methylation defects of additional imprinted loci, and the frequency of developmental delay and congenital anomalies was higher among these patients than those with isolated epimutations, indicating that hypomethylation of multiple imprinted loci is associated with increased diversity of clinical presentation. Among 194 patients with clinical features of an imprinting disorder but no molecular diagnosis, we found 15 (8%) with methylation anomalies, including missed and unexpected molecular diagnoses. These observations broaden the phenotypic and epigenetic definitions of imprinting disorders, and show the importance of comprehensive molecular testing for patient diagnosis and management.

Quality of life in patients with Charcot-Marie-Tooth disease type 1A

We assessed the functional impairment in Charcot-Marie-Tooth resulting from 17p11.2-p12 duplication (CMT1A) patients using the Short-Form Health Survey (SF-36), which is a quality of life questionnaire. Twenty-five patients of both genders aged ≥10 years with a positive molecular diagnosis of CMT1A were selected. Age- and gender-matched Control Group (without family history of neuropathy), and the sociodemographic and professional conditions similar to the patients' group were selected to compare the SF-36 results between them. The results showed that the majority quality of life impairments in CMT1A patients occurred in the social and emotional domains. Functional capacity also tended to be significantly affected; other indicators of physical impairment were preserved. In conclusion, social and emotional aspects are mostly neglected in the assistance provided to CMT1A Brazilian patients, and they should be better understood in order to offer global health assistance with adequate quality of life as a result.

Search for the identification of new genes causing autosomal recessive retinitis pigmentosa

AbstractPurpose The molecular diagnosis of autosomal recessive Retinitis Pigmentosa (arRP) is challenging because of the large genetic and clinical heterogeneity of this disease: to date, 36 arRP genes as well as 3 loci have been identified accounting for approximately 60 % of arRP families. Two major genes, USH2A and EYS, are responsible for 13 to 19 % of the cases, the other genes being minority. Here, we developed a strategy to search for new genes/loci causing arRP in a series of consanguineous families.Methods Inbred families were genotyped using microsatellite markers specific for USH2A and EYS genes. Families resulting from this first screening were analyzed using 250K SNP microarrays with TASE software (Transmitted Allele Search Engine). Known genes in homozygous regions were PCR/sequenced. Whole Exome Sequencing is running for a few families.Results A total of 44 inbred families were analyzed. Among them, 14 (32 %) were fully or partly homozygous for EYS or USH2A markers. We selected 16/30 of the remaining families for SNPs genotyping and homozygosity mapping. We found the causative mutation in 7 families (43 %) in a known gene (RP1, RLBP1, NR2E3, CNGB1, IMPG2, PDE6A) while in 6 others sequencing of known genes in homozygous regions is still ongoing. For the 3 remaining families, potentially new loci were found (in chromosomes 3, 10 and 21) for which the results of whole exome sequencing is being analysed.Conclusion About 43 % of the tested consanguineous families had a positive molecular diagnosis and a candidate gene approach is ongoing for the 3 loci.

Real-time quantitative PCR in cerebral toxoplasmosis diagnosis of Brazilian human immunodeficiency virus-infected patients

Cerebral toxoplasmosis is the most common cerebral mass lesion in AIDS patients in Brazil, and results in high mortality and morbidity, despite free access to HAART (highly active antiretroviral treatment). Molecular diagnosis based on conventional PCR (cnPCR) or real-time quantitative PCR (qrtPCR) has been indispensable for definitive diagnosis. We report here the evaluation of qrtPCR with blood and cerebrospinal fluid (CSF) samples from AIDS patients in Brazil. This prospective study was conducted for 2 years, analysing DNA samples extracted from 149 AIDS patients (98 blood and 51 CSF samples) with confirmed clinical and radiological diagnosis. The laboratory diagnosis included cnPCR (with the B22/B23 primer set) and indirect immunofluorescence (IF). For qrtPCR, two primer sets were simultaneously designed based on described genes and using a 6-carboxyfluorescein dye-labelled TaqMan MGB (minor groove binder) probe. One was B1Tg, which amplified a sequence from the B1 gene. The other was the RETg, which amplified a PCR product of the 529 bp sequence. The overall cnPCR and qrtPCR results were: positive results were observed in 33.6% (50) patients. The sensitivities were 98% for cnPCR (B22/B23), and 86 and 98% for qrtPCR (B1Tg and RETg, respectively). Negative reactions were observed in 66.4% patients. The specificities were 97% for cnPCR and qrtPCR (B1Tg), and 88.8 % for RETg. These data show that RETg PCR is highly sensitive as it amplifies a repeat region with many copies; however, its specificity is lower than the other markers. However, B1Tg PCR had good specificity, but lower sensitivity. Among the patients, 20 had blood and CSF collected simultaneously. Thus, their results permitted us to analyse and compare molecular, serological and clinical diagnosis for a better understanding of the different scenarios of laboratorial and clinical diagnosis. For nine patients with confirmed cerebral toxoplasmosis diagnosis, four scenarios were observed: (i) and (ii) negative molecular diagnosis for CSF and positive for blood with variable IF titres for the sera and CSF (negative or positive); (iii) positive molecular diagnosis with CSF and negative with blood; and (iv) positive molecular diagnosis in both samples. In the latter two situations, normally the IF titres in sera and CSF are variable. Other opportunistic infections were shown in 11 patients. Despite the IF titres in sera and CSF being variable, all of them had negative molecular diagnosis for both samples. qrtPCR allows for a rapid identification of Toxoplasma gondii DNA in patient samples; in a minority of cases discrepancies occur with the cnPCR.

Short and long interval cortical inhibition in patients with Unverricht-Lundborg and Lafora body disease

Myoclonus has different clinical and neurophysiological features in patients with Unverricht-Lundborg (ULD) and Lafora body disease (LBD), probably because of a different cortical hyperexcitability profile. To investigate the role of intracortical inhibition in such different presentations, we used paired-pulse transcranial magnetic stimulation (TMS) in ten ULD and five LBD patients, all with a positive molecular diagnosis. All of the patients were treated with antiepileptic drugs (AEDs). In comparison with healthy subjects, both patient groups had significantly defective short intracortical inhibition (SICI), however LBD patients, but not ULD and healthy subjects, had a clear inhibition at ISI 6 ms and ISI 10 ms. Moreover, defective long interval cortical inhibition (LICI) was found in LBD but not ULD patients. The substantial reduction in SICI suggests that both ULD and LBD patients have impaired inhibitory interneuron pools which are involved in the generation of cortical reflex myoclonus, whereas the inhibition found in LBD patients at ISI 6 and 10 ms, as well the reduced inhibition found at long intervals, suggest a more complex circuitry dysfunction possibly involving both excitatory and inhibitory systems. These findings are probably related to the high epileptogenic propensity characterizing LBD with respect to ULD and to the more severely distorted neuronal network resulting from the pathogenesis of LBD.