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PubMed2002

Allele separation facilitates interpretation of potential splicing alterations and genomic rearrangements.

Mutations that alter normal splice patterns and genomic rearrangements are common causes of hereditary diseases including hereditary nonpolyposis colorectal cancer. However, abnormal transcripts can be difficult to detect and interpret because splicing patterns are often heterogeneous even in normal cells. Standard techniques including sequencing and Southern hybridization fail to detect some genomic rearrangements. We show here that separation of alleles in somatic cell hybrids, through "conversion" technology, considerably facilitates the interpretation of abnormal splicing patterns and the detection of genomic rearrangements. We detected novel mutations in MLH1 in each of four hereditary nonpolyposis colorectal cancer patients. The genomic mutations were CAG>CAA predicting Q346Q; GAG>AAG predicting E102K; a>g at nucleotide 1559-2 at intron 13, and a tandem duplication involving exons 7-12. By separating the two alleles, we showed that one allele produced only abnormal transcript or no transcript whereas the other allele produced only normal transcript. These results allowed pathogenicity to be unambiguously assigned to the mutations and increased the sensitivity of genomic testing.

Adaptor Proteins, Signal Transducing↗

PubMed2025

Newborn screening for common genetic variants associated with permanent hearing loss: Implementation in Ontario and review of the first 3 years.

PURPOSE: Early hearing detection and intervention (EHDI) programs using audiometric screening techniques alone have a limited ability to detect noncongenital childhood permanent hearing loss (PHL). In 2019, Ontario launched universal newborn screening (NBS) for PHL risk factors, including congenital cytomegalovirus and 22 common variants in GJB2 and SLC26A4. Here, we describe our experience in screening for genetic risk factors. METHODS: Ontario newborns who participated in universal newborn hearing screening (UNHS) were offered risk factor screening using dried blood spots (DBS) collected for conventional newborn screening. The screening was conducted using a custom MassArray assay, and positive results were confirmed by Sanger sequencing or polymerase chain reaction. Diagnostic audiological assessments were performed for all screen-positive infants. RESULTS: Of the 412,424 infants screened, 93 had 2 variants in GJB2 or SLC26A4. Of these, 72 had confirmed PHL, 20 had normal hearing, and 1 declined follow-up. Thirteen infants with PHL (1 in 31,724; 11.8% of screen positives) were not identified through audiometric testing as they passed (3) or missed (10) the screening. Importantly, among infants who ultimately received cochlear implants, the detection of genetic etiology through NBS led to an accelerated time to diagnosis, assessment, and intervention. CONCLUSION: Genetic screening has strengthened UNHS and care for infants with or at risk of PHL in Ontario. This study is a step toward the broader inclusion of genomic testing in NBS.

Humans↗

PubMed2003

Quantitative real-time PCR for detection of monkey B virus (Cercopithecine herpesvirus 1) in clinical samples.

A TaqMan based real-time PCR assay was developed for rapid detection and quantitation of herpes B virus (Cercopithecine herpesvirus 1) in clinical samples. The assay utilizes B virus-specific primers and a probe to the non-conserved region of the gG gene to discriminate B virus from closely related alphaherpesviruses. Fifty copies of B virus DNA could be detected with 100% sensitivity with a wide range of quantitation spanning 6 logs. The assay was highly reproducible with intra- and inter-assay coefficients of variation of 0.6 and 2.4%, respectively. Clinical utility of the developed real-time PCR was evaluated by testing genomic DNA prepared from B virus clinical isolates (n=23) and human and monkey clinical specimens (n=62). This novel method was also compared with conventional cell culture with respect to sensitivity and specificity. TaqMan PCR assay was shown to be equally specific and more sensitive than culture method (culture vs. PCR sensitivity 50%) and was able to identify all B virus clinical isolates tested. Fast, reliable assessment of B virus DNA in infected cells and tissues makes real-time PCR assay a valuable tool for diagnosis and management of B virus infections.

Animals↗

PubMed2002

Genomes, multiple origins, and lineage recombination in the Glycine tomentella (Leguminosae) polyploid complex: histone H3-D gene sequences.

Relationships among the various diploid and polyploid taxa that comprise Glycine tomentella have been hypothesized from crossing studies, isozyme data, and repeat length variation for the 5S nuclear ribosomal gene loci. However, several key questions have persisted, and detailed phylogenetic evidence from homoeologous nuclear genes has been lacking. The histone H3-D locus is single copy in diploid Glycine species and has been used to elucidate relationships among diploid races of G. tomentella, providing a framework for testing genome origins in the polyploid complex. For all six G. tomentella polyploid races (T1-T6), alleles at two homoeologous histone H3-D loci were isolated and analyzed phylogenetically with alleles from diploid Glycine species, permitting the identification of all of the homoeologous genomes of the complex. Allele networks were constructed to subdivide groups of homoeologous alleles further, and two-locus genotypes were constructed using these allele classes. Results suggest that some races have more than one origin and that interfertility within races has led to lineage recombination. Most alleles in polyploids are identical or closely related to alleles in diploids, suggesting recency of polyploid origins and spread beyond Australia. These features parallel the other component of the Glycine subgenus Glycine polyploid complex, G. tabacina, one of whose races shares a diploid genome with a G. tomentella polyploid race.

Alleles↗

PubMed1997

Genomic scanning and the transmission/disequilibrium test: analysis of error rates.

A multi-allelic extension of the transmission/disequilibrium test (TDT) was applied to quantitative data from GAW10 Problem 2A by using thresholds to define affection status. Every one of 367 marker loci was screened. It was found that TDT results at neighboring loci are uncorrelated in these data (where the markers are in linkage equilibrium). It was also found that the chi-square statistics for both tests are larger than they should be so that the probability of false linkage detections is increased. Alternative approaches to the chi-square should be considered for assessing statistical significance. Results at marker D5G15 were strong, probably because of linkage without association.

Alleles↗

PubMedDate not supplied

The beta-subunit of follicle-stimulating hormone is deleted in patients with aniridia and Wilms' tumour, allowing a further definition of the WAGR locus.

One in 10,000 children develops Wilms' tumour, an embryonal malignancy of the kidney. Although most Wilms' tumours are sporadic, a genetic predisposition is associated with aniridia, genito-urinary malformations and mental retardation (the WAGR syndrome). Patients with this syndrome typically exhibit constitutional deletions involving band p13 of one chromosome 11 homologue. It is likely that these deletions overlap a cluster of separate but closely linked genes that control the development of the kidney, iris and urogenital tract (the WAGR complex). A discrete aniridia locus, in particular, has been defined within this chromosomal segment by a reciprocal translocation, transmitted through three generations, which interrupts 11p13. In addition, the specific loss of chromosome 11p alleles in sporadic Wilms' tumours has been demonstrated, suggesting that the WAGR complex includes a recessive oncogene, analogous to the retinoblastoma locus on chromosome 13. In WAGR patients, the inherited 11p deletion is thought to represent the first of two events required for the initiation of a Wilms' tumour, as suggested by Knudson from epidemiological data. We have now isolated the deleted chromosomes 11 from four WAGR patients in hamster-human somatic cell hybrids, and have tested genomic DNA from the hybrids with chromosome 11-specific probes. We show that 4 of 31 markers are deleted in at least one patient, but that of these markers, only the gene encoding the beta-subunit of follicle-stimulating hormone (FSHB) is deleted in all four patients. Our results demonstrate close physical linkage between FSHB and the WAGR locus, suggest a gene order for the four deleted markers and exclude other markers tested from this region. In hybrids prepared from a balanced translocation carrier with familial aniridia, the four markers segregate into proximal and distal groups. The translocation breakpoint, which identifies the position of the aniridia gene on 11p, is immediately proximal to FSHB, in the interval between FSHB and the catalase gene.

Adult↗

PubMed2026

Aligning awareness, systems and policy to increase equitable access to genomically driven cancer care.

Genomic testing has the potential to transform cancer care across the patient pathway. However, its benefits remain unevenly realised across populations and health systems. Precision oncology is characterised by a strong promissory discourse, with expectations of improved outcomes and cost-effectiveness, yet real-world implementation remains variable and context dependent. This review examines how patient and public awareness interacts with, and is constrained by, structural, organisational and political-economic factors that shape equitable access to genomically driven cancer care across five themes: (1) the power of patient and public advocacy; (2) learning from the patient perspective; (3) culturally responsive communication; (4) structural and personal barriers and facilitators and (5) political economy of health. Examples are mapped across global regions to highlight how health system, structural and societal factors continue to limit the universal realisation of genomic medicine's benefits. We present four recommendations to strengthen the translation of awareness into equitable access and clinical impact: (1) expand and adequately power genomic studies in underserved populations; (2) improve risk communication and decision-making across the cancer pathway; (3) equitable validation and interpretation of emerging genomic technologies and (4) generate real-world evidence on access, uptake and outcomes of genome-matched therapies. Embedding awareness, trust, access and equity in future initiatives is imperative to realise the promise of precision medicine for all patients.

Biomarkers↗

PubMed2006

Genomic variations and transcriptional regulation of the human mu-opioid receptor gene.

The mu-opioid receptor (MOR1) is a target of endogenous and exogenous opioids and plays a pivotal role for anesthesia and analgesia. Variations in the 5' flanking sequence of the mu-opioid receptor gene may influence transcriptional regulation and ultimately alter protein expression of MOR1. In the present study we investigated the influence of eight single nucleotide polymorphisms (SNP) within the mu-opioid receptor promoter on promoter activity and evaluated the frequencies of the relevant SNPs in 700 patients under opioid medication. Reporter-gene-constructs were created by means of PCR and site directed mutagenesis, testing eight SNPs previously described. The neuroblastoma cell line SHSY5Y was used for transfection and promoter activity was estimated by luciferase activity. Of the eight reporter gene constructs employed to test genomic variations, two produced a significant change in luciferase activity when compared to wild-type constructs. The G-554A variation located within a known NFkB binding element resulted in a decreased activity whereas the A/G base exchange at position -1320 showed an increased luciferase activity. This particular variant generated a myeloid zinc finger (MZF1) cis-acting element known to impact transcription. The allele frequency of the -1320G variant was 0.21% in 700 Caucasian patients under opioid medication in contrast to 9.1% reported previously in drug addicted African Americans. Because of this unexpected low frequency an association analysis to opioid requirements and effects of mu-opioid receptor agonists was not feasible. In conclusion, transcriptional regulation of MOR1 is modified by two genetic variations at positions -554 and -1320 of the mu-opioid receptor promoter. Individuals presenting these variations may have an altered level of MOR expression. A possible association of these genomic variants on efficacy and side effects of opioid treatment in different ethnic groups has to be elucidated.

5' Flanking Region↗

PubMed2026

Immune dysregulatory disorders: perspective from solving a diagnostic odyssey.

PURPOSE OF REVIEW: Inborn errors of immunity (IEIs), once considered rare disorders characterized primarily by recurrent infections, are now recognized as a rapidly expanding group of diseases encompassing autoimmunity, autoinflammation, allergy, malignancy, and immune dysregulation. Advances in next-generation sequencing, functional immunology, and systems biology have revealed overlap between traditionally distinct disease categories and highlighted the complexity of genotype-phenotype relationships. RECENT FINDINGS: While this evolution has led to the discovery of hundreds of previously unrecognized disorders, it has also challenged conventional diagnostic paradigms and demonstrated how patients may have care spread across multiple specialties, without a clear medical home. These discoveries have also highlighted ongoing challenges translating scientific findings to the clinic including difficulties in accessing genomic testing, interpretation of variants of uncertain significance, impacts of incomplete penetrance and somatic mosaicism, and limited availability of specialized functional assays. Emerging computational approaches, including artificial intelligence, offer opportunities to accelerate diagnosis but cannot replace comprehensive clinical evaluation or longitudinal physician-patient relationships. SUMMARY: This perspective examines how the diagnostic odyssey for immune dysregulatory disorders has evolved, side-by-side with the changing framework for diagnosing rare immune diseases. We propose an integrated approach combining clinical phenotyping, genomics, functional validation, and multidisciplinary expertise to unite ongoing discovery between clinicians and scientists, diagnostics, and patient outcomes.

diagnostic odyssey↗

PubMed2026

Synergistic engineering of Casδ nuclease for robust genome editing.

Casδ is a recently identified evolutionary transitional CRISPR system characterized by its compact size (~900 amino acids), broad temperature tolerance, and guidance by a short crRNA without the requirement of a tracrRNA. However, the low editing efficiency of Casδ in eukaryotic cells limits its application. Here, we have developed a hierarchical engineering strategy to improve the genome editing activity of Casδ-1, with optimization focused on enhancing its interactions with the crRNA, the protospacer adjacent motif (PAM) duplex, the single-stranded DNA substrate, and the RNA-DNA heteroduplex. Through this strategy, we successfully generated an activity-enhanced Casδ-1 variant, designated enCasδ, which harbors 9 amino acid substitutions that synergistically augment its editing efficiency. In human cell lines, enCasδ showed 1.3- to 29.3-fold higher editing activity than the wild-type Casδ-1 across ten tested genomic loci, with an average editing efficiency of 54.6%. In addition, enCasδ also mediated robust genome editing in maize; its editing efficiency increased by an average of 5.3-fold relative to Casδ-1, and reached up to an average of 80% at the TS4 and PSY1 loci in stable transgenic lines. The overall editing performance of enCasδ was comparable to that of Streptococcus pyogenes Cas9 (SpCas9) and other Cas12 nucleases. Collectively, enCasδ represents a highly optimized Casδ-1 variant that broadens the applicability of the Casδ CRISPR system and facilitates robust genome editing in both animal cells and plants.

Gene Editing↗

PubMed1996

[Childhood spinal muscular atrophies].

Current knowledge of infantile spinal muscular atrophies (ISA) is reviewed by analyzing cases seen by the neurology service at Hospital Sant Joan de Déu in Barcelona from 1978 through 1986. The assessment is mainly clinical. The total number of patients is 60, as follows: 24 with severe or type I forms, 24 with intermediate or type II forms and 12 with type III forms. All type I patients presented hypotonia and weakness before age four months and died before the age of two years. DNA genome tests were performed for eight, revealing that four had deletions in the seventh and eighth exons. One patient had a single deletion in exon 7, one had a deletion in the neuronal apoptosis inhibitory protein gene as well as in exon 7. No deletions were detected in two patients. Four type II patients died of respiratory complications. All except one acquired autonomous sedestation. Severe scoliosis presented in 14 patients, with most requiring corsets. Fourteen required arthrodesis of the spinal column by way of Luque's technique. DNA genome studies were performed for 19, revealing that 14 had deletions in both exons 7 and 8. Exon 7 deletion was present in two. Two also had deletions in exon 3, an abnormality known as the "Spanish mutation". Genetic conversion or an equivalent deletion in exon 7 was observed in the remaining patients. Five of the type III patients walked autonomously, although with pelvic balancing and Gower's maneuver upon rising from the floor. Braces were required for walking by four, whereas three walked so precariously that they only achieved partial autonomy inside the home. DNA genome studies were performed in seven, revealing exon 7 and 8 deletions in six patients. Only one presented a partial deletion in exon three.

Adolescent↗

PubMed2026

Network-Integrated Platform for Clinical Trial Navigation from the New South Wales Early Phase Clinical Trials Alliance.

PURPOSE: Access to early-phase clinical trials (EPCT) is increasingly constrained by delays in genomic testing and lack of coordinated system-level navigation. The New South Wales Early Phase Clinical Trials Alliance (NECTA) was established to improve EPCT access. Practical Assessment of NECTA Network Assistance in Cancer Outpatient Trials Access (PANNA-COTA) prospectively evaluated whether integrating circulating tumor DNA (ctDNA) profiling with a real-time, cross-site molecular tumor board (MTB) facilitates EPCT enrollment. PATIENTS AND METHODS: In this multicenter prospective study across nine NECTA sites, patients referred for EPCT consideration underwent ctDNA testing using the Guardant360 74-gene assay. The results were reviewed at a fortnightly MTB incorporating cross-site trial mapping and dynamic eligibility review. The primary endpoint was proportion enrolled into EPCTs. Secondary endpoints included ctDNA findings and trial outcomes. RESULTS: Of 104 consented participants, 101 were eligible. Participants had advanced, heavily pretreated solid tumors; 48% lacked prior tumor next-generation sequencing. ctDNA alterations were detected in 85%, with actionable alterations in 44%. Therapeutic options were identified in 88%, and EPCTs were recommended in 76%. Despite this, only 7% of participants received genomically matched therapy. In contrast, 37% enrolled in EPCTs within 3 months and 47% overall [95% confidence interval (CI), 0.37-0.56]. Among evaluable participants on trial, the disease control rate was 81% and objective response rate was 33%. CONCLUSIONS: PANNA-COTA demonstrates that integrating liquid biopsy with real-time, network-level trial navigation enables high rates of EPCT enrollment despite low rates of genomically matched therapy. These findings indicate that clinical trial access is influenced by navigation, eligibility, and system-level coordination rather than genomic actionability alone.

Humans↗

PubMed2005

EVOPRINTER, a multigenomic comparative tool for rapid identification of functionally important DNA.

Here, we describe a multigenomic DNA sequence-analysis tool, evoprinter, that facilitates the rapid identification of evolutionary conserved sequences within the context of a single species. The evoprinter output identifies multispecies-conserved DNA sequences as they exist in a reference DNA. This identification is accomplished by superimposing multiple reference DNA vs. test-genome pairwise blat (blast-like alignment tool) readouts of the reference DNA to identify conserved nucleotides that are shared by all orthologous DNAs. evoprinter analysis of well characterized genes reveals that most, if not all, of the conserved sequences are essential for gene function. For example, analysis of orthologous genes that are shared by many vertebrates identifies conserved DNA in both protein-encoding sequences and noncoding cis-regulatory regions, including enhancers and mRNA microRNA binding sites. In Drosophila, the combined mutational histories of five or more species affords near-base pair resolution of conserved transcription factor DNA-binding sites, and essential amino acids are revealed by the nucleotide flexibility of their codon-wobble position(s). Conserved small peptide-encoding genes, which had been undetected by conventional gene-prediction algorithms, are identified by the codon-wobble signatures of invariant amino acids. Also, evoprinter allows one to assess the degree of evolutionary divergence between orthologous DNAs by highlighting differences between a selected species and the other test species.

Animals↗

PubMed2005

A functional polymorphism within the MRP1 gene locus identified through its genomic signature of positive selection.

Searching for genomic evidence of positive selection has been hailed as an attractive strategy for identifying functional polymorphisms. Here, we demonstrate the feasibility of identifying functional polymorphism at the MRP1 gene locus using this strategy. The 190 kDa MRP1 protein is an efflux pump that regulates the accumulation of xenobiotics and drugs in cells. Functional sequence variations within this gene might account, in part, for inter-individual and population differences in drug response. To identify single nucleotide polymorphisms (SNPs) within the MRP1 gene with potentially important functional significance, we scanned for genomic signatures of recent positive selection at this locus in approximately 480 individuals sampled from the Chinese, Malay, Indian, European-American and African-American populations. The genetic profile of SNPs at this locus revealed high haplotype diversity and weak linkage disequilibrium (LD). Despite this weak LD, major allele G of SNP 5'FR/G-260C contained within a high frequency haplotype exhibited extended haplotype homozygosity across 135 kb in European-Americans. Using two independent genomic tests, long-range haplotype (LRH) test and the F(ST) statistic, we found statistical evidence of positive selection for this allele in the European-American population. When this SNP was recapitulated in an in vitro MRP1 promoter-reporter assay, significantly lower activity was observed from the G-containing promoter when compared with the C-containing promoter in all four cell lines that we tested (P<0.01). These observations confirm the power of this strategy in identifying functionally different alleles of genes and suggest that the different alleles at this SNP locus in the MRP1 gene may account, in part, for inter-individual variations and population differences in drug response.

Genomics↗

PubMed2000

Chromosomal changes in somatic cells in seminoma patients after treatment with ionizing radiation or cytostatics.

Seminomas are sensitive to both ionizing radiation and cytostatic drugs. The study's objective was to find out the effects of cytostatics or ionizing radiation by comparing the results of genome testing before treatment and immediately afterwards. Repeat cytogenetic testing six months after completion of treatment was used to find out changes resulting from reparatory processes after various types of treatment and the degree of elimination of defective lymphocytes from circulation. Three cytogenetic tests were used in our study to find out structural changes in chromosomes (percentage of aberrations), sister chromatid exchanges (SCE) and the number of micronuclei in binuclear lymphocytes (MN). In patients treated with ionizing radiation, strong inhibition of the mitotic activity of lymphocytes occurred after irradiation of para-aortal and ipsilateral inguinal lymph nodes. However, it is difficult to make a connection between the mitotic activity of lymphocytes and their total number, which was found to be within a normal range throughout the study. There is, therefore, another possibility, i.e. that this process actually involves impairment of intracellular enzymes and blockage of the synthesis of macromolecules in lymphocytes which have suffered a large degree of genome damage. Six months after a completed course of irradiation, mitotic activity was found to be mostly normal; however, there was still a very high percentage of aberrations compared with group II (patients treated with a cytostatic, paraplatin) or with respect to the control group, in which the average percentage of aberrations was 1.42 (excluding dicentrics and rings, which are found in all irradiated patients). From the cytological-mutagenetic point of view, chemotherapy proved to be less aggressive to patients. The results of recovery were visible earlier and the elimination of damaged cells was quicker.

Adolescent↗

PubMed2026

Whole genome sequencing reveals a specific microbiota in subglottic stenosis C. acnes may contribute to inflammation.

PURPOSE: Subglottic stenosis (SGS) progressively reduces the airway below the vocal folds. The cause is not known and there is a recurrent need of surgical treatment. Including all phenotypes, SGS affects 1/400 000/yr, with a female dominance. Previous studies have revealed a possible role of the Mycobacterium complex in SGS development. Our hypothesis is that microbiota is associated with the inflammation in SGS, if true it might affect the prevailing treatment options. METHODS: This prospective cross-sectional study included biopsies from 34 patients with subglottic stenosis, collected between 2020 and 2023. Nucleic acids were extracted from the tissue samples and analysed using whole genome sequencing. Microbial composition was characterized using taxonomic profiling of sequencing data. Species with sufficient read counts were selected for further validation using sequence alignment methods to ensure accuracy of identification. RESULTS: Using the most comprehensive form of genomic testing currently in clinical use, we present curated and stable data on the presence of Cutibacterium acnes in 28 out of the 34 cases. CONCLUSION: Cutibacterium acnes may serve as a driver of the inflammation characterizing SGS and should be considered in therapeutically oriented future studies.

Cutibacterium acnes↗

PubMed2025

Next-generation sequencing in breast cancer: current clinical applications and future directions.

INTRODUCTION: Breast cancer is a heterogeneous disease that claims 670,000 lives by 2022. Omic technologies, particularly next generation sequencing (NGS) offers promising avenues for precision medicine. American Society of Clinical Oncology (ASCO) outlines genomic testing's utility, emphasizing prognostic and diagnostic potential. OBJECTIVES: This review succinctly explores NGS's evolution and clinical applications of NGS in breast cancer, thereby guiding future research to enhance patient care. METHODS: Comprehensive literature searches were conducted using databases such as PubMed, Google Scholar, and ResearchGate, focusing on keywords including breast cancer, HER-2 low breast cancer, circulating tumour DNA, single-cell RNA sequencing, and next-generation sequencing. Peer-reviewed, high-quality articles published in English were selected for inclusion. RESULTS: Previous studies have explored the evolution of NGS technology and its clinical applications in breast cancer, including genomic and transcriptomic characterization, treatment guidance, and resistance prediction. Molecular profiling of challenging entities such as early-onset breast cancer and HER-2 low tumours was summarized, with key findings highlighted. This review also discusses emerging technologies, including circulating DNA and single-cell sequencing, as promising avenues for discovery. CONCLUSION: NGS has revealed the genomic and transcriptomic diversity of breast cancer, identifying actionable alterations associated with chemotherapy response and resistance to therapies such as trastuzumab, TKIs, and CDK4/6 inhibitors. Circulating tumour DNA (ctDNA) shows potential for diagnosis, prediction, prognosis, and monitoring, despite tumour heterogeneity. Single-cell analysis enables exploration of individual cell transcriptomes, though high costs and low throughput remain barriers to widespread adoption. HER2-low tumours continue to pose significant research challenges.

Humans↗

PubMed1998

A simple screening test for variant transthyretins associated with familial transthyretin amyloidosis using isoelectric focusing.

Variant forms of the plasma protein transthyretin (TTR) are associated with the most frequently occurring type of familial systemic amyloidosis. Organ system involvement in transthyretin type amyloidosis (ATTR) is often similar to that which occurs in light chain amyloid disease (AL). The proper diagnosis of ATTR is important since treatment (liver transplantation) differs from that in AL (chemotherapy). We present a two-step test to screen sera for variant TTRs using non-denaturing gel electrophoresis performed in 7.5% acrylamide (PAGE) followed by isoelectric focusing (IEF) between pH 4.0 and 7.0 in 2.5 M urea. Serum samples from 110 patients with amyloidosis and their relatives were tested using this IEF technique and compared to genetic mutation results. Sera from patients with ATTR who underwent liver transplantation were also examined prior to and following surgery. IEF analysis showed the presence of both wild-type and variant TTR in 74 of the 110 serum samples tested. Genomic DNA from peripheral blood was used to identify TTR gene mutations in 77 of the 110 patients. Fifteen variants including Val122Ile, preponderant in the African-American population, could be demonstrated by IEF. The sensitivity of IEF was 96% (74/77) and the specificity was 100% (33/33). The predictive values for a positive or negative result were 100% (74/74) and 92% (33/36), respectively. There were no false-positive results and 4% (3/77) false-negative results. In sera from patients with ATTR who underwent liver transplantation, variant TTR was detected by IEF before, but not after, surgery. A simple, accurate, sensitive method is presented as a useful screening test for variant transthyretins associated with ATTR.

Amyloidosis↗