Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
DisciplineDiscipline
-
Is Peer ReviewedIs Peer Reviewed
-
Item TypeItem Type
-
SubjectSubject
-
YearFrom:-To:
-
More FiltersMore FiltersSourceLanguage
Done
Filters
Reset
46
result(s) for
"Reif, Silke"
Sort by:
Next-generation sequencing in X-linked intellectual disability
2015
X-linked intellectual disability (XLID) is a genetically heterogeneous disorder with more than 100 genes known to date. Most genes are responsible for a small proportion of patients only, which has hitherto hampered the systematic screening of large patient cohorts. We performed targeted enrichment and next-generation sequencing of 107 XLID genes in a cohort of 150 male patients. Hundred patients had sporadic intellectual disability, and 50 patients had a family history suggestive of XLID. We also analysed a sporadic female patient with severe ID and epilepsy because she had strongly skewed X-inactivation. Target enrichment and high parallel sequencing allowed a diagnostic coverage of >10 reads for ~96% of all coding bases of the XLID genes at a mean coverage of 124 reads. We found 18 pathogenic variants in 13 XLID genes (AP1S2, ATRX, CUL4B, DLG3, IQSEC2, KDM5C, MED12, OPHN1, SLC9A6, SMC1A, UBE2A, UPF3B and ZDHHC9) among the 150 male patients. Thirteen pathogenic variants were present in the group of 50 familial patients (26%), and 5 pathogenic variants among the 100 sporadic patients (5%). Systematic gene dosage analysis for low coverage exons detected one pathogenic hemizygous deletion. An IQSEC2 nonsense variant was detected in the female ID patient, providing further evidence for a role of this gene in encephalopathy in females. Skewed X-inactivation was more frequently observed in mothers with pathogenic variants compared with those without known X-linked defects. The mutation rate in the cohort of sporadic patients corroborates previous estimates of 5-10% for X-chromosomal defects in male ID patients.
Journal Article
SOS1 is the second most common Noonan gene but plays no major role in cardio-facio-cutaneous syndrome
by
Zweier, Christiane
,
Matejas, Verena
,
Doerr, Helmuth-Guenther
in
Amino Acid Sequence
,
Biological and medical sciences
,
Body Height
2007
Background: Heterozygous gain-of-function mutations in various genes encoding proteins of the Ras-MAPK signalling cascade have been identified as the genetic basis of Noonan syndrome (NS) and cardio-facio-cutaneous syndrome (CFCS). Mutations of SOS1, the gene encoding a guanine nucleotide exchange factor for Ras, have been the most recent discoveries in patients with NS, but this gene has not been studied in patients with CFCS. Methods and results: We investigated SOS1 in a large cohort of patients with disorders of the NS–CFCS spectrum, who had previously tested negative for mutations in PTPN11, KRAS, BRAF, MEK1 and MEK2. Missense mutations of SOS1 were discovered in 28% of patients with NS. In contrast, none of the patients classified as having CFCS was found to carry a pathogenic sequence change in this gene. Conclusion: We have confirmed SOS1 as the second major gene for NS. Patients carrying mutations in this gene have a distinctive phenotype with frequent ectodermal anomalies such as keratosis pilaris and curly hair. However, the clinical picture associated with SOS1 mutations is different from that of CFCS. These findings corroborate that, despite being caused by gain-of-function mutations in molecules belonging to the same pathway, NS and CFCS scarcely overlap genotypically.
Journal Article
A novel R486Q mutation in BMPR1B resulting in either a brachydactyly type C/symphalangism-like phenotype or brachydactyly type A2
by
Seemann, Petra
,
Morin, Gilles
,
Boergermann, Jan
in
Adult
,
Bioinformatics
,
Biological and medical sciences
2006
Heterozygous missense mutations in the serine-threonine kinase receptor BMPR1B result typically in brachydactyly type A2 (BDA2), whereas mutations in the corresponding ligand GDF5 cause brachydactyly type C (BDC). Mutations in the GDF inhibitor Noggin (NOG) or activating mutations in GDF5 cause proximal symphalangism (SYM1). Here, we describe a novel mutation in BMPR1B (R486Q) that is associated with either BDA2 or a BDC/SYM1-like phenotype. Functional investigations of the R486Q mutation were performed and compared with the previously reported BDA2-causing mutation R486W and WT BMPR1B. Overexpression of the mutant receptors in chicken micromass cultures resulted in a strong inhibition of chondrogenesis with the R486Q mutant, showing a stronger effect than the R486W mutant. To investigate the consequences of the BMPR1B mutations on the intracellular signal transduction, we used stably transfected C2C12 cells and measured the activity of SMAD-dependent and SMAD-independent pathways. SMAD activation after stimulation with GDF5 was suppressed in both mutants. Alkaline phosphatase induction showed an almost complete loss of activation by both mutants. Our data extend the previously known mutational and phenotypic spectrum associated with mutations in BMPR1B. Disturbances of NOG-GDF5-BMPR1B signaling cascade can result in similar clinical manifestations depending on the quantitative effect and mode of action of the specific mutations within the same functional pathway.
Journal Article
Schimke immunoosseous dysplasia: suggestions of genetic diversity
2007
Schimke immunoosseous dysplasia (SIOD), which is characterized by prominent spondyloepiphyseal dysplasia, T‐cell deficiency, and focal segmental glomerulosclerosis, is a panethnic autosomal recessive multisystem disorder with variable expressivity. Biallelic mutations in switch/sucrose nonfermenting (swi/snf) &!ndash;related, matrix‐associated, actin‐dependent regulator of chromatin, subfamily a‐like 1 (SMARCAL1) are the only identified cause of SIOD. However, among 72 patients from different families, we identified only 38 patients with biallelic mutations in the coding exons and splice junctions of the SMARCAL1 gene. This observation, the variable expressivity, and poor genotype–phenotype correlation led us to test several hypotheses including modifying haplotypes, oligogenic inheritance, or locus heterogeneity in SIOD. Haplotypes associated with the two more common mutations, R820H and E848X, did not correlate with phenotype. Also, contrary to monoallelic SMARCAL1 coding mutations indicating oligogenic inheritance, we found that all these patients did not express RNA and/or protein from the other allele and thus have biallelic SMARCAL1 mutations. We hypothesize therefore that the variable expressivity among patients with biallelic SMARCAL1 mutations arises from environmental, genetic, or epigenetic modifiers. Among patients without detectable SMARCAL1 coding mutations, our analyses of cell lines from four of these patients showed that they expressed normal levels of SMARCAL1 mRNA and protein. This is the first evidence for nonallelic heterogeneity in SIOD. From analysis of the postmortem histopathology from two patients and the clinical data from most patients, we propose the existence of endophenotypes of SIOD. Hum Mutat 28(3), 273–283, 2007. Published 2006, Wiley‐Liss, Inc.
Journal Article
Regulation of CD4+ and CD8+ T Cell Biology by Short-Chain Fatty Acids and Its Relevance for Autoimmune Pathology
by
Reif, Andreas
,
Visekruna, Alexander
,
Schiweck, Carmen
in
Antigens
,
Autoimmune diseases
,
Bacteria
2022
The gut microbiota encodes a broad range of enzymes capable of synthetizing various metabolites, some of which are still uncharacterized. One well-known class of microbiota-derived metabolites are the short-chain fatty acids (SCFAs) such as acetate, propionate, butyrate and valerate. SCFAs have long been considered a mere waste product of bacterial metabolism. Novel results have challenged this long-held dogma, revealing a central role for microbe-derived SCFAs in gut microbiota-host interaction. SCFAs are bacterial signaling molecules that act directly on host T lymphocytes by reprogramming their metabolic activity and epigenetic status. They have an essential biological role in promoting differentiation of (intestinal) regulatory T cells and in production of the anti-inflammatory cytokine interleukin-10 (IL-10). These small molecules can also reach the circulation and modulate immune cell function in remote tissues. In experimental models of autoimmune and inflammatory diseases, such as inflammatory bowel disease, multiple sclerosis or diabetes, a strong therapeutic potential of SCFAs through the modulation of effector T cell function was observed. In this review, we discuss current research activities toward understanding a relevance of microbial SCFA for treating autoimmune and inflammatory pathologies from in vitro to human studies.
Journal Article
Studying dietary intake in daily life through multilevel two-part modelling: a novel analytical approach and its practical application
by
Reif, Andreas
,
Ebner-Priemer, Ulrich
,
Matura, Silke
in
analytical methods
,
Behavioral Sciences
,
Clinical Nutrition
2021
Background
Understanding which factors influence dietary intake, particularly in daily life, is crucial given the impact diet has on physical as well as mental health. However, a factor might influence whether but not how much an individual eats and vice versa or a factor’s importance may differ across these two facets. Distinguishing between these two facets, hence, studying dietary intake as a dual process is conceptually promising and not only allows further insights, but also solves a statistical issue. When assessing the association between a predictor (e.g. momentary affect) and subsequent dietary intake in daily life through ecological momentary assessment (EMA), the outcome variable (e.g. energy intake within a predefined time-interval) is semicontinuous. That is, one part is equal to zero (i.e. no dietary intake occurred) and the other contains right-skewed positive values (i.e. dietary intake occurred, but often only small amounts are consumed). However, linear multilevel modelling which is commonly used for EMA data to account for repeated measures within individuals cannot be applied to semicontinuous outcomes. A highly informative statistical approach for semicontinuous outcomes is multilevel two-part modelling which treats the outcome as generated by a dual process, combining a multilevel logistic/probit regression for zeros and a multilevel (generalized) linear regression for nonzero values.
Methods
A multilevel two-part model combining a multilevel logistic regression to predict whether an individual eats and a multilevel gamma regression to predict how much is eaten, if an individual eats, is proposed. Its general implementation in R, a widely used and freely available statistical software, using the R-package brms is described. To illustrate its practical application, the analytical approach is applied exemplary to data from the Eat2beNICE-APPetite-study.
Results
Results highlight that the proposed multilevel two-part model reveals process-specific associations which cannot be detected through traditional multilevel modelling.
Conclusions
This paper is the first to introduce multilevel two-part modelling as a novel analytical approach to study dietary intake in daily life. Studying dietary intake through multilevel two-part modelling is conceptually as well as methodologically promising. Findings can be translated to tailored nutritional interventions targeting either the occurrence or the amount of dietary intake.
Journal Article
Studying Microtemporal, Within-Person Processes of Diet, Physical Activity, and Related Factors Using the APPetite-Mobile-App: Feasibility, Usability, and Validation Study
by
Reif, Andreas
,
Ebner-Priemer, Ulrich
,
Matura, Silke
in
Activities of daily living
,
Appetite
,
Diet
2021
Background: Diet and physical activity (PA) have a major impact on physical and mental health. However, there is a lack of effective strategies for sustaining these health-protective behaviors. A shift to a microtemporal, within-person approach is needed to capture dynamic processes underlying eating behavior and PA, as they change rapidly across minutes or hours and differ among individuals. However, a tool that captures these microtemporal, within-person processes in daily life is currently not present. Objective: The APPetite-mobile-app is developed for the ecological momentary assessment of microtemporal, within-person processes of complex dietary intake, objectively recorded PA, and related factors. This study aims to evaluate the feasibility and usability of the APPetite-mobile-app and the validity of the incorporated APPetite-food record. Methods: The APPetite-mobile-app captures dietary intake event-contingently through a food record, captures PA continuously through accelerometers, and captures related factors (eg, stress) signal-contingently through 8 prompts per day. Empirical data on feasibility (n=157), usability (n=84), and validity (n=44) were collected within the Eat2beNICE-APPetite-study. Feasibility and usability were examined in healthy participants and psychiatric patients. The relative validity of the APPetite-food record was assessed with a subgroup of healthy participants by using a counterbalanced crossover design. The reference method was a 24-hour recall. In addition, the energy intake was compared with the total energy expenditure estimated from accelerometry. Results: Good feasibility, with compliance rates above 80% for prompts and the accelerometer, as well as reasonable average response and recording durations (prompt: 2.04 min; food record per day: 17.66 min) and latencies (prompts: 3.16 min; food record: 58.35 min) were found. Usability was rated as moderate, with a score of 61.9 of 100 on the System Usability Scale. The evaluation of validity identified large differences in energy and macronutrient intake between the two methods at the group and individual levels. The APPetite-food record captured higher dietary intakes, indicating a lower level of underreporting, compared with the 24-hour recall. Energy intake was assessed fairly accurately by the APPetite-food record at the group level on 2 of 3 days when compared with total energy expenditure. The comparison with mean total energy expenditure (2417.8 kcal, SD 410) showed that the 24-hour recall (1909.2 kcal, SD 478.8) underestimated habitual energy intake to a larger degree than the APPetite-food record (2146.4 kcal, SD 574.5). Conclusions: The APPetite-mobile-app is a promising tool for capturing microtemporal, within-person processes of diet, PA, and related factors in real time or near real time and is, to the best of our knowledge, the first of its kind. First evidence supports the good feasibility and moderate usability of the APPetite-mobile-app and the validity of the APPetite-food record. Future findings in this context will build the foundation for the development of personalized lifestyle modification interventions, such as just-in-time adaptive interventions.
Journal Article
The moderating role of diet and physical activity in insulin resistance and immunometabolic depression
2025
Insulin resistance (IR) and atypical depression share an immunometabolic pathway and present major health risks. Although IR has been associated with atypical depression, its link to immunometabolic depression (IMD) symptoms is less understood. Lifestyle factors like physical activity (PA) and diet may mitigate these conditions through anti-inflammatory and antidiabetic effects. This study examines how lifestyle factors moderate the IR-IMD relationship. We conducted a cross-sectional analysis using baseline data from the
m
PRIME study (n = 124). IR was measured via HOMA-IR, and IMD symptoms (hypersomnia, hyperphagia, loss of energy, tiredness) were assessed using a composite score derived from four Beck Depression Inventory-II items that have been previously linked to immunometabolic alterations. PA was tracked using accelerometers; diet via the empirical dietary inflammatory pattern (EDIP). Multiple linear regression and moderation analyses were applied. Ninety-four individuals (M(age) = 49.43, SD = 13.93; 48% IR) were analyzed. IR was significantly associated with the IMD-score (
β
= 0.817,
p
= 0.001). PA showed no direct or moderating effect (
p
> 0.05). A proinflammatory diet moderated the IR-IMD link in men (
β
= 0.718,
p
< 0.001), but not women (
p
> 0.05). Findings indicate an IR-IMD association, suggesting symptom monitoring in IR patients may aid early IMD detection and prevention.
Trial registration
Registered at
https://www.drks.de/search/de/trial/DRKS00022774
Identifier no. DRKS00022774 (Registration date: 2021-03-08).
Journal Article
The heart knows best: baseline heart rate variability as guide to transcutaneous auricular vagus nerve stimulation in depression
by
Zhao, Tong
,
Hanssen, Ruth
,
Aichholzer, Mareike
in
631/477/2811
,
692/53/2423
,
692/699/476/1414
2025
Major Depressive Disorder can be conceptualized as a chronic stress condition associated with autonomic dysregulation, including blunted heart rate reactivity, elevated basal cortisol levels and higher low-grade peripheral inflammation, pointing to an autonomic imbalance with relative sympathetic overactivation and parasympathetic attenuation. Transcutaneous vagus nerve stimulation (taVNS) offers a non-invasive method to stimulate the vagus nerve, as key component of the parasympathetic system, to restore autonomic balance. Here, we examined whether emotional (i.e., positive and negative emotions), cardiac (i.e., heart rate and heart rate variability (HRV)), and inflammatory (i.e., TNF- α, IL-6) reactivity to stress are differentially influenced by taVNS in participants with MDD and controls. Additionally, we performed a post-hoc analysis with participants stratified by baseline RMSSD, as a proxy for vagus nerve activity, to evaluate the utility of biological stratification beyond diagnostic criteria. To assess the effect of chronic stress we conducted a single-blinded, cross-over, randomized controlled trial with 110 participants (51 controls and 59 MDD participants). For the analysis stratified by RMSSD group, we grouped participants into low (n = 54) vs. high (n = 55) RMSSD groups, regardless of diagnosis. All participants were subjected to an acute stress paradigm, both with taVNS and sham stimulation on two separate days, in a counter-balanced order. There was no difference in any of the outcomes regarding the effect of taVNS in participants with MDD and controls. Analyses split by RMSSD group, however, showed that for those with low RMSSD, taVNS restored the blunted cardiac stress response and numerically decreased TNF-α levels. Unexpectedly, in participants with high RMSSD, the opposite pattern was observed: heart rate and TNF-α were significantly increased, and vagally mediated heart rate variability was significantly decreased under taVNS compared to sham stimulation. Analyses using RMSSD as continuous predictor yielded similar results. Our findings suggest that RMSSD-based stratification may be a useful tool for predicting outcome of (ta)VNS treatment. We encourage researchers with HRV data to re-evaluate their findings through RMSSD stratification.
Journal Article