Jan Hellemans

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BACKGROUND Currently, a lack of consensus exists on how best to perform and interpret quantitative real-time PCR (qPCR) experiments. The problem is exacerbated by a lack of sufficient experimental detail in many publications, which impedes a reader's ability to evaluate critically the quality of the results presented or to repeat the experiments. CONTENT(More)
Although quantitative PCR (qPCR) is becoming the method of choice for expression profiling of selected genes, accurate and straightforward processing of the raw measurements remains a major hurdle. Here we outline advanced and universally applicable models for relative quantification and inter-run calibration with proper error propagation along the entire(More)
We report heterozygous mutations in the genes encoding either type I or type II transforming growth factor beta receptor in ten families with a newly described human phenotype that includes widespread perturbations in cardiovascular, craniofacial, neurocognitive and skeletal development. Despite evidence that receptors derived from selected mutated alleles(More)
Osteopoikilosis, Buschke-Ollendorff syndrome (BOS) and melorheostosis are disorders characterized by increased bone density. The occurrence of one or more of these phenotypes in the same individual or family suggests that these entities might be allelic. We collected data from three families in which affected individuals had osteopoikilosis with or without(More)
Reverse transcription quantitative PCR (RT-qPCR) is considered today as the gold standard for accurate, sensitive and fast measurement of gene expression. Unfortunately, what many users fail to appreciate is that numerous critical issues in the workflow need to be addressed before biologically meaningful and trustworthy conclusions can be drawn. Here, we(More)
Nephronophthisis (NPHP) is the most frequent genetic cause of chronic renal failure in children. Identification of four genes mutated in NPHP subtypes 1-4 (refs. 4-9) has linked the pathogenesis of NPHP to ciliary functions. Ten percent of affected individuals have retinitis pigmentosa, constituting the renal-retinal Senior-Loken syndrome (SLSN). Here we(More)
Copy number changes are known to be involved in numerous human genetic disorders. In this context, qPCR-based copy number screening may serve as the method of choice for targeted screening of the relevant disease genes and their surrounding regulatory landscapes. qPCR has many advantages over alternative methods, such as its low consumable and(More)
RNA transcripts such as mRNA or microRNA are frequently used as biomarkers to determine disease state or response to therapy. Reverse transcription (RT) in combination with quantitative PCR (qPCR) has become the method of choice to quantify small amounts of such RNA molecules. In parallel with the democratization of RT-qPCR and its increasing use in(More)
There is growing interest in digital PCR (dPCR) because technological progress makes it a practical and increasingly affordable technology. dPCR allows the precise quantification of nucleic acids, facilitating the measurement of small percentage differences and quantification of rare variants. dPCR may also be more reproducible and less susceptible to(More)
The XML-based Real-Time PCR Data Markup Language (RDML) has been developed by the RDML consortium (http://www.rdml.org) to enable straightforward exchange of qPCR data and related information between qPCR instruments and third party data analysis software, between colleagues and collaborators and between experimenters and journals or public repositories. We(More)