Introduction: Rapid, high throughput diagnostics are a valuable tool, allowing the detection of SARS-CoV-2 in populations, in order to identify and isolate people with asymptomatic and symptomatic infections. Reagent shortages and restricted access to high throughput testing solutions have limited the effectiveness of conventional assays such as reverse transcriptase quantitative PCR (RTqPCR), particularly throughout the first months of the pandemic. We investigated the use of LamPORE, where loop mediated isothermal amplification (LAMP) is coupled to nanopore sequencing technology, for the detection of SARS CoV 2 in symptomatic and asymptomatic populations. Methods: In an asymptomatic prospective cohort; health care workers across four sites (Birmingham, Southampton, Basingstoke and Manchester) self swabbed with nasopharyngeal swabs weekly for three weeks and supplied a saliva specimen daily. These samples were tested for SARS CoV 2 RNA using the Oxford Nanopore LamPORE system and a reference RTqPCR assay on extracted sample RNA. A second retrospective cohort of 848 patients with influenza like illness from March 2020 to June 2020, were similarly tested from nasopharyngeal swabs. Results: In the asymptomatic cohort a total of 1200 participants supplied 23,427 samples (3,966 swab, 19,461 saliva) over a three-week period. The incidence of SARS CoV 2 was 0.95% using LamPORE. Diagnostic sensitivity and specificity was > 99.5% in both swab and saliva asymptomatic samples as compared to the reference RTqPCR test. In the retrospective symptomatic cohort, the incidence was 13.4% and the sensitivity and specificity were 100%. Conclusions: LamPORE is a highly accurate methodology for the detection of SARS CoV 2 in both the symptomatic and asymptomatic population settings and can be used as an alternative to RTqPCR.

Next generation sequencing has disrupted genetic testing, allowing far more scope in the tests applied. The appropriate sections of the genome to be tested can now be readily selected, from single mutations to whole-genome sequencing. One product offering within this spectrum are focused exomes, targeting ~5,000 genes know to be implicated in human disease. These are designed to offer a flexible platform offering high diagnostic yield with a reduction in sequencing requirement compared to whole exome sequencing. Here, we have undertaken sequencing of control DNA samples and compare two kits, the Illumina TruSight One and the Agilent SureSelect Focused Exome. Characteristics of the kits are comprehensively evaluated. Despite the larger design region of the Agilent kit, we find that the Illumina kit performs better in terms of gene coverage, as well as coverage of clinically relevant loci. We provide exhaustive coverage statistics for each kit to aid the assessment of their suitability and provide read data for control DNA samples to allow for bioinformatic benchmarking by users developing pipelines for these data.

Nystagmus is a disorder of uncontrolled eye movement and can occur as an isolated trait (idiopathic INS, IINS) or as part of multisystem disorders such as albinism, significant visual disorders or neurological disease. Eighty-one unrelated patients with nystagmus underwent routine ocular phenotyping using commonly available phenotyping methods and were grouped into four sub-cohorts according to the level of phenotyping information gained and their findings. DNA was extracted and sequenced using a broad utility next generation sequencing (NGS) gene panel. A clinical subpanel of genes for nystagmus/albinism was utilised and likely causal variants were prioritised according to methods currently employed by clinical diagnostic laboratories. We determine the likely underlying genetic cause for 43.2% of participants with similar yields regardless of prior phenotyping. This study demonstrates that a diagnostic workflow combining basic ocular phenotyping and a clinically available targeted NGS panel, can provide a high diagnostic yield for patients with infantile nystagmus, enabling access to disease specific management at a young age and reducing the need for multiple costly, often invasive tests. By describing diagnostic yield for groups of patients with incomplete phenotyping data, it also permits the subsequent design of 'real-world' diagnostic workflows and illustrates the changing role of genetic testing in modern diagnostic workflows for heterogeneous ophthalmic disorders.

Activated PI3K-delta Syndrome (APDS), also called PI3K-delta activating mutation causing senescent T cells, lymphadenopathy, and immunodeficiency (PASLI), is an autosomal dominant disorder caused by inherited or de novo gain-of-function mutations in one of two genes encoding subunits of the phosphoinositide-3-kinase delta (PI3Kδ) complex. This largely leukocyte-restricted protein complex regulates cell growth, activation, proliferation, and survival. Patients who harbor these mutations have early onset immunodeficiency with recurrent infections, lymphadenopathy, and autoimmunity. The most common infection susceptibilities are sinopulmonary (encapsulated bacteria) and herpesviruses. Multiple defects in both innate and adaptive immune function are responsible for this phenotype. Apart from anti-microbial prophylaxis and immunoglobulin replacement, patients are treated with a variety of immunomodulatory agents and some have needed hematopoietic stem cell transplants. Here, we highlight the spectrum of infections, immune defects, and therapy options in this inborn error of immunity.

Oculocutaneous albinism (OCA) and ocular albinism (OA) are inherited disorders of melanin biosynthesis, resulting in loss of pigment and severe visual deficits. OCA encompasses a range of subtypes with overlapping, often hypomorphic phenotypes. OCA1 is the most common cause of albinism in European populations and is inherited through autosomal recessive mutations in the Tyrosinase ( TYR) gene. However, there is a high level of reported missing heritability, where only a single heterozygous mutation is found in TYR . This is also the case for other OCA subtypes including OCA2 caused by mutations in the OCA2 gene. Here we have interrogated the genetic cause of albinism in a well phenotyped, hypomorphic albinism population by sequencing a broad gene panel and performing segregation studies on phenotyped family members. Of eighteen probands we can confidently diagnose three with OA and OCA2, and one with a PAX6 mutation. Of six probands with only a single heterozygous mutation in TYR , all were found to have the two common variants S192Y and R402Q. Our results suggest that a combination of R402Q and S192Y with a deleterious mutation in a ‘tri-allelic genotype’ can account for missing heritability in some hypomorphic OCA1 albinism phenotypes.

Next-generation sequencing is radically changing how DNA diagnostic laboratories operate. What started as a single-gene profession is now developing into gene panel sequencing and whole-exome and whole-genome sequencing (WES/WGS) analyses. With further advances in sequencing technology and concomitant price reductions, WGS will soon become the standard and be routinely offered. Here, we focus on the critical steps involved in performing WGS, with a particular emphasis on points where WGS differs from WES, the important variables that should be taken into account, and the quality control measures that can be taken to monitor the process. The points discussed here, combined with recent publications on guidelines for reporting variants, will facilitate the routine implementation of WGS into a diagnostic setting.

The recent discovery of somatically acquired CALR mutations in a substantial proportion of patients with myeloproliferative neoplasms has provided a new marker of clonal disease, advancing both diagnosis and prognosis in these previously difficult to characterise disorders. The mutations, which can be challenging to detect on a routine basis, are heterogeneous insertions/deletions (indels) in exon 9 with mutant allele burden that vary substantially between patients. We evaluated four genetic screening methods for their ability to detect a series of different CALR mutations; Sanger sequencing, fragment analysis PCR, high resolution melt (HRM) and targeted next generation sequencing (NGS). The limit of detection (LoD) of each assay was tested using serial dilution series made with DNA from CALR positive sample DNA and a cell line, MARIMO, found to carry a heterozygous 61 nucleotide CALR deletion. All methods were capable of detecting each mutation; HRM and fragment analysis PCR were better at detecting low mutation levels compared to Sanger sequencing but targeted NGS had the lowest LoD at a 1% mutation burden.

Whole-exome sequencing provides a cost-effective means to sequence protein coding regions within the genome, which are significantly enriched for etiological variants. We describe a panel of single nucleotide polymorphisms (SNPs) to facilitate the validation of data provenance in whole-exome sequencing studies. This is particularly significant where multiple processing steps necessitate transfer of sample custody between clinical, laboratory and bioinformatics facilities. SNPs captured by all commonly used exome enrichment kits were identified, and filtered for possible confounding properties. The optimised panel provides a simple, yet powerful, method for the assignment of intrinsic, highly discriminatory identifiers to genetic samples.

Since the development of technologies that can determine the base-pair sequence of DNA, the ability to sequence genes has contributed much to science and medicine. However, it has remained a relatively costly and laborious process, hindering its use as a routine biomedical tool. Recent times are seeing rapid developments in this field, both in the availability of novel sequencing platforms, as well as supporting technologies involved in processes such as targeting and data analysis. This is leading to significant reductions in the cost of sequencing a human genome and the potential for its use as a routine biomedical tool. This review is a snapshot of this rapidly moving field examining the current state of the art, forthcoming developments and some of the issues still to be resolved prior to the use of new sequencing technologies in routine clinical diagnosis.

The validation and verification of laboratory methods and procedures before their use in clinical testing is essential for providing a safe and useful service to clinicians and patients. This paper outlines the principles of validation and verification in the context of clinical human molecular genetic testing. We describe implementation processes, types of tests and their key validation components, and suggest some relevant statistical approaches that can be used by individual laboratories to ensure that tests are conducted to defined standards.

BACKGROUND:Indirect alternatives to sequencing as a method for mutation scanning are of interest to diagnostic laboratories because they have the potential for considerable savings in both time and costs. Ideally, such methods should be simple, rapid, and highly sensitive, and they should be validated formally to a very high standard. Currently, most reported methods lack one or more of these characteristics. We describe the optimization and validation of conformation-sensitive capillary electrophoresis (CSCE) for diagnostic mutation scanning.METHODS:We initially optimized the performance of CSCE with a systematic panel of plasmid-based controls. We then compared manual analysis by visual inspection with automated analysis by BioNumerics software (Applied Maths) in a blinded interlaboratory validation with 402 BRCA1 (breast cancer 1, early onset) and BRCA2 (breast cancer 1, early onset) variants previously characterized by Sanger sequencing.RESULTS:With automated analysis, we demonstrated a sensitivity of >99% (95% CI), which is indistinguishable from the sensitivity for conventional sequencing by capillary electrophoresis. The 95% CI for specificity was 90%-93%; thus, CSCE greatly reduces the number of fragments that need to be sequenced to fully characterize variants. By manual analysis, the 95% CIs for sensitivity and specificity were 98.3%-99.4% and 93.1%-95.5%, respectively.CONCLUSIONS:CSCE is amenable to a high degree of automation, and analyses can be multiplexed to increase both capacity and throughput. We conclude that once it is optimized, CSCE combined with analysis with BioNumerics software is a highly sensitive and cost-effective mutation-scanning technique suitable for routine genetic diagnostic analysis of heterozygous nucleotide substitutions, small insertions, and deletions.