CFTR genotype and maximal exercise capacity in cystic fibrosis: a cross-sectional study

RATIONALE: Cystic fibrosis transmembrane conductance regulator (CFTR) is expressed in human skeletal muscle cells. Variations of CFTR dysfunction among patients with CF may present an important determinant of aerobic exercise capacity in CF. Previous studies on the relationship between CFTR genotype and aerobic exercise capacity are scarce and contradictory. OBJECTIVES: This study was designed to explore factors influencing aerobic exercise capacity, expressed as peak oxygen consumption (VO2peak) with a specific focus on CFTR genotype in children and adults with CF. METHODS: In an international, multicenter cross-sectional study we collected data on CFTR genotype and cardiopulmonary exercise tests (CPET) in patients with CF eight years and older. CFTR mutations were classified into functional classes I-V. RESULTS: The final analysis included 726 patients (45% females, age 8 to 61 years, FEV1 16 to 123 % predicted) from 17 CF centers in North America, Europe, Australia and Asia whom all had both valid maximal CPET and complete CFTR genotype data. Overall, patients exhibited exercise intolerance (VO2peak, 77.3±19.1 % predicted), but values were comparable among different CFTR classes. Using linear regression analysis adjusted for relevant confounders, lung function and body mass index, but not CFTR genotype were the main predictors of VO2peak. CONCLUSIONS: We conclude that lung disease severity and reduced nutritional status rather than CFTR genotypes are the major determinants of aerobic exercise capacity in patients with CF

Progression of pulmonary hyperinflation and trapped gas associated with genetic and environmental factors in children with cystic fibrosis

BACKGROUND: Functional deterioration in cystic fibrosis (CF) may be reflected by increasing bronchial obstruction and, as recently shown, by ventilation inhomogeneities. This study investigated which physiological factors (airway obstruction, ventilation inhomogeneities, pulmonary hyperinflation, development of trapped gas) best express the decline in lung function, and what role specific CFTR genotypes and different types of bronchial infection may have upon this process. METHODS: Serial annual lung function tests, performed in 152 children (77 males; 75 females) with CF (age range: 6–18 y) provided data pertaining to functional residual capacity (FRC(pleth), FRC(MBNW)), volume of trapped gas (V(TG)), effective specific airway resistance (sR(eff)), lung clearance index (LCI), and forced expiratory indices (FVC, FEV(1), FEF(50)). RESULTS: All lung function parameters showed progression with age. Pulmonary hyperinflation (FRC(pleth )> 2SDS) was already present in 39% of patients at age 6–8 yrs, increasing to 67% at age 18 yrs. The proportion of patients with V(TG )> 2SDS increased from 15% to 54% during this period. Children with severe pulmonary hyperinflation and trapped gas at age 6–8 yrs showed the most pronounced disease progression over time. Age related tracking of lung function parameters commences early in life, and is significantly influenced by specific CFTR genotypes. The group with chronic P. aeruginosa infection demonstrated most rapid progression in all lung function parameters, whilst those with chronic S. aureus infection had the slowest rate of progression. LCI, measured as an index of ventilation inhomogeneities was the most sensitive discriminator between the 3 types of infection examined (p < 0.0001). CONCLUSION: The relationships between lung function indices, CFTR genotypes and infective organisms observed in this study suggest that measurement of other lung function parameters, in addition to spirometry alone, may provide important information about disease progression in CF

Cutaneous squamous cell carcinoma in an autosomal-recessive Adams-Oliver syndrome patient with a novel frameshift pathogenic variant in the EOGT gene.

Aplasia cutis congenita (ACC) of the scalp and terminal transverse limb defects (TTLD) are the characteristic findings of Adams-Oliver syndrome (AOS). The variable clinical spectrum further includes cardiac, neurologic, renal, and ophthalmological findings. Associated genes in AOS are in the Notch and the CDC42/Rac1 signaling pathways. Both autosomal-dominant and autosomal-recessive inheritances have been reported, the latter with pathogenic variants in DOCK6 or EOGT. The EOGT-associated recessive type of AOS has been postulated to present a more favorable prognosis. We here report a 12-year-old girl from a refugee family of Iraq with consanguineous parents. She was born with a severe phenotype of AOS presenting a large ACC of the scalp with an underlying skull defect, which was often infected and inflamed. Afterward, additional ulceration developed. Furthermore, the girl showed microcephaly, TTLD on both hands and feet, and neurological findings: spastic paresis, epilepsy and suspicion of intellectual deficit. Molecular genetic analysis (next-generation sequencing) revealed a novel frameshift mutation in the EOGT gene in Exon 13 in homozygous constellation: c.1013dupA p.(Asn338Lysfs*24). A biopsy within an ulceration at the scalp ACC showed a cutaneous squamous cell carcinoma (cSCC) with local invasive growth into the dura, the meninges, and the cortex. Treatment including surgical resection and focal irradiation was not curative and the girl deceased 6 months after initial diagnosis. This report on a patient with AOS and an autosomal-recessive EOGT gene variant dying of a local aggressive cSCC at an ACC lesion shows that close monitoring of ACC is essential

Characterization of two novel intronic OPA1 mutations resulting in aberrant pre-mRNA splicing.

BACKGROUND We report two novel splice region mutations in OPA1 in two unrelated families presenting with autosomal-dominant optic atrophy type 1 (ADOA1) (ADOA or Kjer type optic atrophy). Mutations in OPA1 encoding a mitochondrial inner membrane protein are a major cause of ADOA. METHODS We analyzed two unrelated families including four affected individuals clinically suspicious of ADOA. Standard ocular examinations were performed in affected individuals of both families. All coding exons, as well as exon-intron boundaries of the OPA1 gene were sequenced. In addition, multiplex ligation-dependent probe amplification (MLPA) was performed to uncover copy number variations in OPA1. mRNA processing was monitored using RT-PCR and subsequent cDNA analysis. RESULTS We report two novel splice region mutations in OPA1 in two unrelated individuals and their affected relatives, which were previously not described in the literature. In one family the heterozygous insertion and deletion c.[611-37_611-38insACTGGAGAATGTAAAGGGCTTT;611-6_611-16delCATATTTATCT] was found in all investigated family members leading to the activation of an intronic cryptic splice site. In the second family sequencing of OPA1 disclosed a de novo heterozygous deletion c.2012+4_2012+7delAGTA resulting in exon 18 and 19 skipping, which was not detected in healthy family members. CONCLUSION We identified two novel intronic mutations in OPA1 affecting the correct OPA1 pre-mRNA splicing, which was confirmed by OPA1 cDNA analysis. This study shows the importance of transcript analysis to determine the consequences of unclear intronic mutations in OPA1 in proximity to the intron-exon boundaries

Quantitative methods for the analysis of CFTR transcripts/splicing variants

AbstractIn cystic fibrosis (CF), transcript analysis and quantification are important for diagnosis, prognosis and also as surrogate markers for some therapies including gene therapy. Classical RNA-based methods require significant expression levels in target samples for appropriate analysis, thus PCR-based methods are evolving towards reliable quantification. Various protocols for the quantitative analysis of CFTR transcripts (including those resulting from splicing variants) are described and discussed here

Molecular and biochemical characterisation of a novel mutation in POLG associated with Alpers syndrome

<p>Abstract</p> <p>Background</p> <p>DNA polymerase γ (<it>POLG</it>) is the only known mitochondrial DNA (mtDNA) polymerase. It mediates mtDNA replication and base excision repair. Mutations in the <it>POLG </it>gene lead to reduction of functional mtDNA (mtDNA depletion and/or deletions) and are therefore predicted to result in defective oxidative phosphorylation (OXPHOS). Many mutations map to the polymerase and exonuclease domains of the enzyme and produce a broad clinical spectrum. The most frequent mutation p.A467T is localised in the linker region between these domains. In compound heterozygote patients the p.A467T mutation has been described to be associated amongst others with fatal childhood encephalopathy. These patients have a poorer survival rate compared to homozygotes.</p> <p>Methods</p> <p>mtDNA content in various tissues (fibroblasts, muscle and liver) was quantified using quantitative PCR (qPCR). OXPHOS activities in the same tissues were assessed using spectrophotometric methods and catalytic stain of BN-PAGE.</p> <p>Results</p> <p>We characterise a novel splice site mutation in <it>POLG </it>found <it>in trans </it>with the p.A467T mutation in a 3.5 years old boy with valproic acid induced acute liver failure (Alpers-Huttenlocher syndrome). These mutations result in a tissue specific depletion of the mtDNA which correlates with the OXPHOS-activities.</p> <p>Conclusions</p> <p>mtDNA depletion can be expressed in a high tissue-specific manner and confirms the need to analyse primary tissue. Furthermore<it>, POLG </it>analysis optimises clinical management in the early stages of disease and reinforces the need for its evaluation before starting valproic acid treatment.</p

Personalisierte Medizin: Grundlagen für die interprofessionelle Aus-, Weiter- und Fortbildung von Gesundheitsfachleuten

Hinweise zur Ausarbeitung dieser Publikation: Die SAMW hat im Auftrag der Akademien der Wissenschaften Schweiz die thematische Plattform «Chancen und Risiken der Personalisierten Gesundheit» etabliert. In diesem Rahmen hat der SAMW-Vorstand eine Arbeitsgruppe beauftragt, das Thema der Aus-, Weiter- und Fortbildung von Gesundheitsfachleuten im Bereich «Personalisierte Medizin» zu bearbeiten

Evaluation of genome-wide loci of iron metabolism in hereditary hemochromatosis identifies PCSK7 as a host risk factor of liver cirrhosis

Genome-wide association studies (GWAS) have revealed genetic determinants of iron metabolism, but correlation of these with clinical phenotypes is pending. Homozygosity for HFE C282Y is the predominant genetic risk factor for hereditary hemochromatosis (HH) and may cause liver cirrhosis. However, this genotype has a low penetrance. Thus, detection of yet unknown genetic markers that identify patients at risk of developing severe liver disease is necessary for better prevention. Genetic loci associated with iron metabolism (TF, TMPRSS6, PCSK7, TFR2 and Chr2p14) in recent GWAS and liver fibrosis (PNPLA3) in recent meta-analysis were analyzed for association with either liver cirrhosis or advanced fibrosis in 148 German HFE C282Y homozygotes. Replication of associations was sought in additional 499 Austrian/Swiss and 112 HFE C282Y homozygotes from Sweden. Only variant rs236918 in the PCSK7 gene (proprotein convertase subtilisin/kexin type 7) was associated with cirrhosis or advanced fibrosis (P = 1.02 × 10−5) in the German cohort with genotypic odds ratios of 3.56 (95% CI 1.29-9.77) for CG heterozygotes and 5.38 (95% CI 2.39-12.10) for C allele carriers. Association between rs236918 and cirrhosis was confirmed in Austrian/Swiss HFE C282Y homozygotes (P = 0.014; ORallelic = 1.82 (95% CI 1.12-2.95) but not in Swedish patients. Post hoc combined analyses of German/Swiss/Austrian patients with available liver histology (N = 244, P = 0.00014, ORallelic = 2.84) and of males only (N = 431, P = 2.17 × 10−5, ORallelic = 2.54) were consistent with the premier finding. Association between rs236918 and cirrhosis was not confirmed in alcoholic cirrhotics, suggesting specificity of this genetic risk factor for HH. PCSK7 variant rs236918 is a risk factor for cirrhosis in HH patients homozygous for the HFE C282Y mutatio