a-robust-polymerase-chain-reaction-based-assay-for-quantifying

A Robust Polymerase Chain Reaction-based Assay for Quantifying Cytosine-guanine-guanine Trinucleotide Repeats in Fragile X Mental Retardation-1 Gene

Fragile X syndrome (FXS) and associated disorders are caused by expansion of the cytosine-guanine-guanine (CGG) trinucleotide repeat in the 5&#8217; ...

The Chinese University of Hong Kong

Before 2003, most children with acute lymphoblastic leukaemia (ALL) abandoned treatment, with only approximately 30% treated in China. With the development of national insurance for underprivileged patients, we assessed the current frequency and causes of treatment abandonment among patients with ALL who were enrolled in the Chinese Children's Cancer Group ALL protocol between 2015 and 2016.

Treatment abandonment in childhood acute lymphoblastic leukaemia in China: a retrospective cohort study of the Chinese Children's Cancer Group.

Graft-derived-cell-free DNA (Gcf-DNA) in plasma is a promising biomarker to monitor graft-rejection after liver transplantation (LTx). However, current methods of measuring Gcf-DNA have several limitations including high cost, long turnaround-time and the need to request donor's genetic information. In this study, eleven patients diagnosed with different inborn errors of metabolism (IEMs) who required living-related LTx were enrolled in order to establish a potentially useful noninvasive method to monitor graft damage. Circulating cell-free DNA (cfDNA) was extracted from plasma specimens serially collected at specific time points (day 0, day 1, day 7, day 14, day 30, day 60) after LTx. The distribution of Gcf-DNA fragment sizes was measured using sequencing read lengths and quantified by using Y-chromosome capture methodology in seven sex-mismatched recipients. In the analysis of fragment size distribution, we observed Gcf-DNA exhibited smaller fragment sizes than the recipient-cfDNA. Based on this phenomenon, two fragment sizes (105-145 bp, 160-170 bp) of the cfDNA pool were extracted to enrich Gcf-DNA. Accordingly, the ratio of short fragments to long fragments (S/L-Frag) in cfDNA was calculated. A high S/L-Frag ratio pointed towards an early trend of graft injury when compared to two routine liver function enzymes (ALT and AST) and Gcf-DNA, and it significantly correlated with ALT (P < 0.0001) and AST (P < 0.0001) during full-blown rejection. In conclusion, we established the Gcf-DNA size profile in patients who have undergone living-related LTx and established a potential biomarker to monitor graft function after LTx.

Analysis of fragment size distribution of cell-free DNA: A potential non-invasive marker to monitor graft damage in living-related liver transplantation for inborn errors of metabolism.

The diversity of disease presentations warrants one single assay for detection and delineation of various genomic disorders. Herein, we describe a gel-free and biotin-capture-free mate-pair method through coupling Controlled Polymerizations by Adapter-Ligation (CP-AL). We first demonstrated the feasibility and ease-of-use in monitoring DNA nick translation and primer extension by limiting the nucleotide input. By coupling these two controlled polymerizations by a reported non-conventional adapter-ligation reaction 3' branch ligation, we evidenced that CP-AL significantly increased DNA circularization efficiency (by 4-fold) and was applicable for different sequencing methods but at a faction of current cost. Its advantages were further demonstrated by fully elimination of small-insert-contaminated (by 39.3-fold) with a ∼50% increment of physical coverage, and producing uniform genome/exome coverage and the lowest chimeric rate. It achieved single-nucleotide variants detection with sensitivity and specificity up to 97.3 and 99.7%, respectively, compared with data from small-insert libraries. In addition, this method can provide a comprehensive delineation of structural rearrangements, evidenced by a potential diagnosis in a patient with oligo-atheno-terato-spermia. Moreover, it enables accurate mutation identification by integration of genomic variants from different aberration types. Overall, it provides a potential single-integrated solution for detecting various genomic variants, facilitating a genetic diagnosis in human diseases.

Development of coupling controlled polymerizations by adapter-ligation in mate-pair sequencing for detection of various genomic variants in one single assay.

Emerging studies suggest that low-pass genome sequencing (GS) provides additional diagnostic yield of clinically significant copy-number variants (CNVs) compared with chromosomal microarray analysis (CMA). However, a prospective back-to-back comparison evaluating accuracy, efficacy, and incremental yield of low-pass GS compared with CMA is warranted.

Xiaofan Zhu

Department of Obstetrics and Gynaecology,
Shenzhen Research Institute

The Chinese University of Hong Kong

A Robust Polymerase Chain Reaction-based Assay for Quantifying Cytosine-guanine-guanine Trinucleotide Repeats in Fragile X Mental Retardation-1 Gene

Xiaofan Zhu

Department of Obstetrics and Gynaecology,Shenzhen Research Institute

The Chinese University of Hong Kong

A Robust Polymerase Chain Reaction-based Assay for Quantifying Cytosine-guanine-guanine Trinucleotide Repeats in Fragile X Mental Retardation-1 Gene

Department of Obstetrics and Gynaecology,
Shenzhen Research Institute