Oligonucleotide Hybridization Assay Research Articles

Retrofitting massively parallel sequencing (MPS) for HLA-DQA1 and polymarker (PM) in forensic casework.

Genotype profiling has played a major role in forensics for decades. The technology for detection and discrimination has advanced substantially, from serology to DNA sequence analysis. Currently, there may be situations where there is a need for re-analysis of forensic DNA data that was produced using methodology that is no longer available. An example of this is the allele-specific oligonucleotide hybridization assays used in the 1990s. In the study presented herein, we have developed a multiplex system combining PCR and massively parallel sequencing (MPS) technologies to identify DNA polymorphisms. Our results are consistent with those found in the widely utilized AmpliType PM + DQA1 Amplification and Typing Kit originally marketed by Perkin Elmer. During the course of our studies, it became apparent that paralogous genes for two of the loci, GYPA and HBG2 (formerly HBGG), could have confounded the interpretation of the original assays, and we describe the technical solutions we developed to overcome ambiguity in genotype assignment. This study results in a novel resource enabling the re-analysis of DNA profiling results produced decades past using current day technology.

Enzyme-linked oligonucleotide hybridization assay for direct oligo measurement in blood

Small oligonucleotides (oligos) are increasingly being utilized as diagnostics or treatments for disease. An impediment to broader use is the ability to readily measure oligos in biological fluids. Here, we describe a very straightforward assay with detection in the sub-picomole range that does not require extraction from serum/plasma or polymerization chain reaction amplification. As a result, there are no losses or errors due to sample handling, and the assay can be used to measure oligos modified in a variety of ways that increase therapeutic efficacy. The enzyme-linked oligonucleotide hybridization assay (ELOHA) is based on competition with a detection oligo for hybridization to a capture oligo covalently linked to a solid substrate. The versatility of ELOHAs is demonstrated by application to the measurement of three oligos, including two morpholino-oligos with 3′-octaguanidine derivatization for efficient cell uptake. The third oligo is unmodified and has a DNA sequence equivalent to miR93. The assays have sensitivity as low as 0.28 pmol/sample reaction at 50% hybridization. Adding to clinical utility is the need for only a simple 96-well absorbance plate reader and the finding that neither EDTA nor heparin interferes with detection.

Electrochemiluminescence on digital microfluidics for microRNA analysis.

Electrochemiluminescence (ECL) is a sensitive analytical technique with great promise for biological applications, especially when combined with microfluidics. Here, we report the first integration of ECL with digital microfluidics (DMF). ECL detectors were fabricated into the ITO-coated top plates of DMF devices, allowing for the generation of light from electrically excited luminophores in sample droplets. The new system was characterized by making electrochemical and ECL measurements of soluble mixtures of tris(phenanthroline)ruthenium(II) and tripropylamine (TPA) solutions. The system was then validated by application to an oligonucleotide hybridization assay, using magnetic particles bearing 21-mer, deoxyribose analogues of the complement to microRNA-143 (miRNA-143). The system detects single nucleotide mismatches with high specificity, and has a limit of detection of 1.5 femtomoles. The system is capable of detecting miRNA-143 in cancer cell lysates, allowing for the discrimination between the MCF-7 (less aggressive) and MDA-MB-231 (more aggressive) cell lines. We propose that DMF-ECL represents a valuable new tool in the microfluidics toolbox for a wide variety of applications.

Droplet Digital Enzyme-Linked Oligonucleotide Hybridization Assay for Absolute RNA Quantification.

We present a continuous-flow droplet-based digital Enzyme-Linked Oligonucleotide Hybridization Assay (droplet digital ELOHA) for sensitive detection and absolute quantification of RNA molecules. Droplet digital ELOHA incorporates direct hybridization and single enzyme reaction via the formation of single probe-RNA-probe (enzyme) complex on magnetic beads. It enables RNA detection without reverse transcription and PCR amplification processes. The magnetic beads are subsequently encapsulated into a large number of picoliter-sized droplets with enzyme substrates in a continuous-flow device. This device is capable of generating droplets at high-throughput. It also integrates in-line enzymatic incubation and detection of fluorescent products. Our droplet digital ELOHA is able to accurately quantify (differentiate 40% difference) as few as ~600 RNA molecules in a 1 mL sample (equivalent to 1 aM or lower) without molecular replication. The absolute quantification ability of droplet digital ELOHA is demonstrated with the analysis of clinical Neisseria gonorrhoeae 16S rRNA to show its potential value in real complex samples.

Impact of tumor HPV status on outcome in patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck receiving chemotherapy with or without cetuximab: retrospective analysis of the phase III EXTREME trial.

Tumor human papillomavirus (HPV) status is an important prognostic factor in locoregionally advanced squamous cell carcinoma of the head and neck (SCCHN). Prognostic value in recurrent and/or metastatic (R/M) disease remains to be confirmed. This retrospective analysis of the EXTREME trial, comparing chemotherapy plus cetuximab with chemotherapy first line in R/M SCCHN, investigated efficacy and prognosis according to tumor p16 and HPV status. Paired tissue samples were used: p16INK4A expression was assessed by immunohistochemistry, and HPV status determined in extracted DNA samples using oligonucleotide hybridization assays. Altogether, 416 of 442 patients had tumor samples available for p16 and HPV: 10% of tumors were p16 positive and 5% were HPV positive. Adding cetuximab to chemotherapy improved survival, irrespective of tumor p16 or HPV status. This pattern remained in a combined analysis of p16 and HPV. p16 positivity and HPV positivity were associated with prolonged survival compared with p16 negativity and HPV negativity. Subgroup analysis of patients with oropharyngeal cancer demonstrated a similar pattern to all evaluable patients. The results from this analysis suggest that p16 and HPV status have prognostic value in R/M SCCHN and survival benefits of chemotherapy plus cetuximab over chemotherapy alone are independent of tumor p16 and HPV status.

Isoelectrofocusing and PCR Amplification-Reverse Hybridization Assay in Evaluation of Alpha-1-Antitrypsin Deficiency

Isoelectrofocusing and PCR Amplification-Reverse Hybridization Assay in Evaluation of Alpha-1-Antitrypsin DeficiencyAlpha-1-antitrypsin deficiency is a potentially lethal genetic disorder, which has pulmonary and liver manifestations. The standardized biochemical and molecular diagnostic protocol for detection of clinically relevant alleles is needed. The paper summarizes current concepts about AATD, describes the potentials of isoelectric focusing and PCR amplification-reverse allele specific oligonucleotide hybridization assay in the detection of affected individuals and shortly presents our experiences in the evaluation of AATD. We conclude that the systematic clinical laboratory approach to AATD might be based on the combination of mentioned methods, coordinated by alpha-1-antritrypsin quantification. Additionally, its complete medical implementation is achieved through teamwork between clinical chemists, molecular biologists and clinicians.

Bioluminescence-Based Detection of MicroRNA, miR21 in Breast Cancer Cells

A hybridization assay for the detection of microRNA, miR21 in cancer cells using the bioluminescent enzyme Renilla luciferase (Rluc) as a label, has been developed. MicroRNAs are small RNAs found in plants, animals, and humans that perform key functions in gene silencing and affect early-stage cell development, cell differentiation, and cell death. miRNAs are considered useful early diagnostic and prognostic markers of cancer, candidates for therapeutic intervention, and targets for basic biomedical research. However, methods for highly sensitive and rapid detection of miRNA directly from samples such as cells that can serve as a suitable diagnostics platform are lacking. In that regard, the utilization of the bioluminescent label, Rluc, that offers the advantage of high signal-to-noise ratio, allows for the development of highly sensitive assays for the determination of miRNA in a variety of matrixes. In this paper, we have described the development of a competitive oligonucleotide hybridization assay for the detection of miR21 using the free miR21 and Rluc-labeled miR21 that competes to bind to an immobilized miR21 complementary probe. The miR21 microRNA chosen for this study is of biomedical significance because its levels are elevated in a variety of cancers. Using the optimized assay, a detection limit of 1 fmol was obtained. The assay was employed for the detection of miR21 in human breast adenocarcinoma MCF-7 cells and nontumorigenic epithelial MCF-10A cells. The comparison of miR21 expression level in two cell lines demonstrated higher expression of miR21 in breast cancer cell line MCF-7 compared to the nontumorigenic MCF-10A cells. Further, using the assay developed, the miR21 quantification could be performed directly in cell extracts. The hybridization assay was developed in a microplate format with a total assay time of 1.5 h and without the need for sample PCR amplification. The need for early molecular markers and their detection methods in cancer diagnosis is tremendous. The characteristics of the assay developed in this work show its suitability for early cancer diagnosis based on miRNA as a biomarker.

Developing DNA tiles for oligonucleotide hybridization assay with higher accuracy and efficiency

We demonstrate the versatility of a DNA tile system for oligonucleotide hybridization assay and explored the detection limit of the probe tiles for DNA targets of varied lengths.

PMMA Isocyanate-Modified Digital Discs as a Support for Oligonucleotide-Based Assays

A mild chemical procedure for the derivatization of PMMA as the isocyanate on rigid supports is described. The proposal is based on spin-coating the support with a hydroxy-modified PMMA polymer, followed by treatment with (3-isocyanatopropyl)triethoxysilane, developing an isocyanate-ended PMMA. Oligonucleotide hybridization assays performed on this surface demonstrate that the process is simple and highly effective and agree with the results of other modified materials, including aminated PMMA, gold, and glass. As a demonstration, it has been applied to covalently attached aminated oligonucleotides on a modified audio-video compact disc (CD) surface to perform DNA probe hybridization assays. Measurements were carried out with a CD player, by detecting the solid microspots precipitated from an enzymatic reaction (HRP-TMB). This new approach, being a competitive technique, opens a broad horizon of applications for point of care or in situ needs.

Association between β2-Adrenergic Receptor Genetic Polymorphisms and Nocturnal Asthmatic Patients of Chinese Han Nationality

Background: As a result of the finding that the mutation of Arg into Gly at β₂-adrenergic receptor (β₂-AR)16 loci could promote the downregulation effect triggered by the β₂-agonist, it was supposed that Gly16 might be associated with the downregulation of β₂-AR in patients with nocturnal asthma. Objective: It was the aim of this study to analyze the association between β₂-AR genetic polymorphisms and nocturnal asthmatic patients of Chinese Han nationality. Methods: A polymerase chain reaction allele-specific oligonucleotide hybridization assay was used to determine 16 and 27 loci alleles of β₂-AR genetic polymorphisms in 25 nocturnal asthmatic patients (nocturnal asthma group), 22 non-nocturnal asthmatic patients (non-nocturnal asthma group), and 72 healthy people (control group). All people investigated were of Chinese Han nationality. Results: The distribution frequency of genotype Arg/Arg, Arg/Gly, and Gly/Gly at β₂-AR 16 loci was 12, 16 and 72% in the nocturnal asthma group; and 27, 41 and 32% in the non-nocturnal asthma group. There was a significant increase in the frequency of genotype Gly/Gly and allele Gly in the nocturnal asthma group compared with the non-nocturnal asthma group (p < 0.01). However, there was no significant difference in the frequency of genotype Gly/Gly and allele Gly in the non-nocturnal asthma group, compared with the control group. There was no significance in the frequency of the genotypes and alleles of β₂-AR 27 loci among the three groups (p > 0.05). Conclusion: The Gly16 polymorphism of β₂-AR was overrepresented in nocturnal asthmatic patients, correlated with nocturnal asthma, and therefore appeared to be an important genetic factor in the expression of this asthmatic phenotype.

Association between β2-Adrenergic Receptor Genetic Polymorphisms and Total Serum IgE in Asthmatic Patients of Chinese Han Nationality

Background: β₂-Adrenergic receptor (β₂-AR) polymorphisms occurring at amino acid position 16 (Arg-Gly) and 27 (Gln-Glu) are known to be functionally relevant and also disease-modifying in subjects with asthma. It has been found in Caucasoid asthmatic patients that the Gln27 genotype β₂-AR was associated with an increase in total serum IgE levels. The association between β₂-AR genetic polymorphisms and total serum IgE in asthmatic patients of Chinese Han nationality remains to be established.Objectives: It was the aim of this study to investigate the association between β₂-AR genetic polymorphisms and total serum IgE in asthmatic patients of Chinese Han nationality. Methods: All 59 asthmatic patients investigated (27 males and 32 females, aged between 16 and 60 years) were people of Chinese Han nationality. They were tested for their total serum IgE levels with the enzyme-linked immunosorbent assay test, and β₂-AR genetic polymorphisms were tested with the polymerase chain reaction allele-specific oligonucleotide hybridization assay. Results: There was a significant difference of serum IgE levels among three β₂-AR 27 loci groups (p < 0.0001), with the highest IgE level [(1.24 ± 0.25) × 10⁶ IU/l] in the Gln/Gln group and the lowest IgE level [(0.48 ± 0.06) × 10⁶ IU/l] in the Glu/Glu group. No polymorphism of β₂-AR 16 loci was found to be associated with total serum IgE (p > 0.05). Conclusions: Our research suggested that in asthmatic patients of Chinese Han nationality, the β₂-AR genetic polymorphism at 27 loci could be associated with serum IgE levels and it might therefore play an important role in the determination of phenotypes of bronchial asthma.

Photocrosslinking oligonucleotide hybridization assay for concurrent gene dosage and CpG methylation analysis.

The phenotypic effects of aberrant gene expression are indistinguishable, regardless of whether the underlying mutation is one of gene copy number (deletion or duplication) or modification of differentially methylated CpG sites occurring in critical regulatory sequences in gene promoters. The XLnt photocrosslinking oligonucleotide technology provides for the hybridization-dependent covalent attachment of probe to target, allowing survival of the probe/target complex under otherwise denaturing conditions. Posthybridization wash stringency can be substantially higher than under standard techniques, leading to a marked increase in signal-to-noise ratios. In addition, the reduction in nonspecific background provides linearity to XLnt-based oligonucleotide assays comparable to that otherwise achieved only with very long probes. The technology is thus ideally suited for combining the high-throughput capacity of oligonucleotide hybridization platforms with accurate measurement of relative gene dosage. By integrating the XLnt system with an assay design separating probe/target immobilization and signal elaboration functions, relative gene dosage assessment can be applied to the quantitation of fractional resistance to methylation-sensitive restriction enzyme (MSRE) digestion. The method described below provides for the development of photocrosslinking oligonucleotide assays for relative gene dosage and fractional locus CpG methylation in a microtiter plate-based format.

A Single Nucleotide Primer Extension Assay to Detect the APC I1307K Gene Variant

Adenomatous polyposis coli (APC) is a tumor suppressor gene important in colorectal tumorigenesis. A genetic variant of APC, I1307K, results from a T-to-A transversion at nucleotide 3920 which converts the wild-type sequence to a homopolymer tract (A(8)). The I1307K alteration is not itself oncogenic, but creates a hypermutable region (A(8)) that is prone to frame-shift mutations. The APC I1307K variant occurs in approximately 6% of the Ashkenazi Jewish population and is reported to approximately double an individual's risk for colorectal cancer. Here we describe a single nucleotide primer extension assay for the detection of the APC I1307K mutation. Following PCR amplification, nucleotide 3920 of the APC gene is directly sequenced using single nucleotide primer extension technology. The assay is in a multiplex format allowing simultaneous forward and reverse sequencing of the I1307K variant, which provides an internal, independent confirmation of each testing result. The assay was validated against 60 samples previously characterized by an allele-specific oligonucleotide (ASO) hybridization assay, with 100% concordance of results. Compared to the ASO assay, this single nucleotide primer extension assay requires significantly less technical time to perform, and has a greatly increased throughput capacity. The single nucleotide extension assay provides a highly sensitive and specific assay to identify individuals with the APC I1307K gene variant who may benefit from increased colorectal screening.

Use of denaturing HPLC and a heteroduplex generator to detect the HFE C282Y mutation associated with genetic hemochromatosis.

Hereditary hemochromatosis (HH) is a common autosomal recessive disorder of iron metabolism. Most individuals with HH are homozygous for a 845G→A missense mutation (C282Y) in the HFE gene that encodes a MHC class I-like protein (1)(2)(3)(4)(5). One in 300 adults of Caucasian descent has this genotype (3)(6). The disease is characterized by increased absorption of dietary iron by the gastrointestinal tract and the progressive deposition of iron in the parenchymal cells. It produces a wide range of clinical complications, including hepatic fibrosis, cirrhosis, hepatocellular carcinoma, diabetes mellitus, hypopituitarism, hypogonadism, arthritis, and cardiomyopathy (7). These complications can be entirely prevented with regular iron removal by phlebotomy. The availability of this effective treatment highlights the value of screening appropriate populations for the C282Y mutation to detect HH before irreversible complications occur (8). Another frequent mutation in the HFE gene, H63D, has been described (1), but the relationship between this mutation and iron overload is less clear. Although compound heterozygotes C282Y/H63D (1) and H63D homozygotes (9) may show some degree of iron overload, the penetrance associated with these genotypes is very low, and clinical features of hemochromatosis, especially liver disease, are rare. In opposition to C282Y, screening the population for H63D is therefore not indicated. An important issue is the development of a cost-effective methodology suitable for genetically testing large numbers of samples for the C282Y mutation. Many methods have been used to detect C282Y, including oligonucleotide ligation assays (1), fragment length polymorphism analyses of PCR products after restriction enzyme digestion (5), allele-specific oligonucleotide hybridization assays (2), mutagenically separated PCR assays (10), primer extension assays (11)(12), and allele refractory mutation systems (13)(14). All of these assays are time-consuming. In addition, they rely on complicated multistep procedures involving radioisotopes or …

Report from a workshop on multianalyte microsphere assays.

Multiplexed assays using fluorescent microspheres is an exciting technique that has been gaining popularity among researchers, particularly those in the public health field. Part of its popularity is due to its flexibility, as both immunoassays and oligonucleotide hybridization assays can be developed on this platform. This report summarizes a workshop held by the Centers for Disease Control and Prevention that discussed issues surrounding these assays and the Luminex 100 xMAP instrument. Topics included instrumentation, assay design, sample matrix and volume, quality control, and development of commercial applications.

High-Throughput Detection of Submicroscopic Deletions and Methylation Status at 15q11-q13 by a Photo-Cross-Linking Oligonucleotide Hybridization Assay

Current technologies for assessing genetic deletions and duplications of greater than one kilobase are labor-intensive or rely on PCR-based methods, and none offers the ability to simultaneously detect dosage abnormalities, assess 5'-to-3' cytosine-guanosine (CpG) methylation, and interrogate single-nucleotide polymorphisms (SNPs). We describe a high-throughput platform for direct gene-dosage determination capable of concurrent assessment of other forms of gene modification. We used a light-activated interstrand nucleic acid cross-linking system (XLnt technology) to determine gene dosage at the 15q11-q13 deletion/duplication locus. We incorporated restriction enzyme digestion of genomic DNA into the method to assess CpG methylation in parallel with gene dosage. For method validation we used DNA from 31 cell lines with previously characterized 15q11-q13 gene dosage and parental origin status. Diagnostic cutoffs were set at 0.5 +/- 0.15, 1 +/- 0.15-0.25, and 2 +/- 0.3. Dosage-only experiments showed discrimination of deletions (n = 21) from healthy controls (NCs; n = 27) in all samples. Five of 49 samples gave results outside of specification. Concurrent evaluation of dosage and CpG methylation yielded dosage results within specification for 18 of 19 deletion and 8 of 12 NC samples. Paternal deletion and NC methylation pattern results were within specification in 17 of 19 and 9 of 12 runs, respectively. No overlap was demonstrated between value sets for the two groups. The XLnt technology provides a rapid, high-throughput platform for the accurate determination of gene dosage. The flexibility of this technology allows parallel interrogation of gene dosage, CpG methylation, and SNPs.

Long-term follow-up of patients with a clinically benign extrahepatic biliary stenosis and K-ras mutation in endobiliary brush cytology

Background: K-ras mutations in endobiliary brush cytology are an early event in carcinogenesis and justify a suspicion of malignancy in patients with extrahepatic biliary stenosis. However, K-ras mutations have been detected in specimens obtained by brushing of clinically benign extrahepatic biliary stenosis. The aim of this study was to determine whether these findings represent an early or false-positive diagnosis of cancer. Methods: Cytologic specimens were obtained by brushing in 312 consecutive patients with extrahepatic biliary stenosis. Mutations in the K-ras oncogene were detected by an enriched polymerase chain reaction and allele-specific oligonucleotide hybridization assay. Eight patients with a K-ras mutation and a clinically benign extrahepatic biliary stenosis were followed. Results: After a median follow-up of 65 months, 6 of the 8 patients were alive without evidence of malignancy. One patient died of congestive heart failure. The other patient died 60 months after the specimen was obtained, possibly because of chronic pancreatitis, although previously there had been suspicion of malignancy. Biopsy specimens from the papilla were negative for neoplasia and the K-ras analysis harbored the same mutation as previously found in the brush specimen. Conclusion: Based on long-term follow-up, the K-ras mutations in all 8 patients with a clinically benign extrahepatic biliary stenosis must be considered as confirmed false-positives. Nevertheless, a false-positive result is infrequent. Therefore, patients with a positive K-ras mutation in biliary cytologic specimens obtained by brushing still require careful, continuing follow-up. (Gastrointest Endosc 2002;55:883-8.)

Familial dysautonomia: detection of the IKBKAP IVS20(+6T --> C) and R696P mutations and frequencies among Ashkenazi Jews.

Familial dysautonomia (FD) is an autosomal recessive congenital neuropathy that occurs almost exclusively in the Ashkenazi Jewish (AJ) population. Mutations in the IkappaB kinase complex-associated protein (IKBKAP) gene cause FD. Two IKBKAP mutations, IVS20(+6T --> C) and R696P, have been identified in FD patients of AJ descent. The splice site mutation IVS20(+6T --> C) is responsible for > 99.5% of known AJ patients with FD, and haplotype analyses were consistent with a common founder. In contrast, the R696P mutation has been identified in only a few AJ patients. To facilitate carrier detection, a single PCR and allele-specific oligonucleotide (ASO) hybridization assay was developed to facilitate the detection of both the IVS20(+6T --> C) and R696P mutations. Screening of 2,518 anonymous AJ individuals from the New York metropolitan area revealed a carrier frequency for IVS20(+6T --> C) of 1 in 32 (3.2%; 95% CI, 2.5-3.9%), similar to the previously estimated carrier frequency (3.3%) based on disease incidence. No carrier was identified for the R696P lesion, indicating that the mutation was rare in this population (< 1 in 2,500). This sensitive and specific assay should facilitate carrier screening for FD mutations in the AJ community, as well as postnatal diagnostic testing.

Polymorphisms of the angiotensinogen gene, the endothelial nitric oxide synthase gene, and the interleukin-1beta gene promoter in women with idiopathic recurrent miscarriage.

Interleukin (IL)-1beta, angiotensinogen (Agt), and endothelium-derived nitric oxide synthase (eNOS) are thought to be involved in idiopathic recurrent miscarriage (IRM). We investigated the correlation between IRM and common polymorphisms in Agt, Nos3 and IL-1beta genes: one polymorphism in the promoter region of the IL-1beta gene, one in exon 2 of the Agt gene, and one in exon 7 of the Nos3 gene. A total of 130 women with a history of IRM and 67 healthy control women were included in the study. Genotyping for the C/T transition at position -511 in the promoter region of IL1B, for the single base M235T polymorphism of Agt, and for the missense Glu298Asp variant of Nos3 was performed using PCR, an allele-specific oligonucleotide hybridization assay, and pyrosequencing, respectively. Allele and genotype frequencies of all polymorphisms were similar among women with IRM and controls. Between women with primary and secondary recurrent miscarriages, no statistically significant differences between allele and genotype frequencies were observed. Despite promising experimental data, our data fall short of showing any significant association between a variant of the promoter region of IL1B, the M235T polymorphism of Agt, and the Glu298Asp missense variant of Nos3 and the occurrence of IRM.

Nonradioactive Detection of the Common Connexin 26 167delT and 35delG Mutations and Frequencies among Ashkenazi Jews

Mutations in the gap junction β2 (GJB2) gene, Connexin 26 (Cx26), cause nonsyndromic sensorineural recessive deafness (NSRD). Two frameshift mutations, 167delT and 35delG, are the most frequent Cx26 lesions causing NSRD. The 35delG mutation is panethnic, while the 167delT lesion occurs almost exclusively in the Ashkenazi Jewish population at a carrier frequency of 2 to 4%. To facilitate carrier detection, a simple nonradioactive allele-specific oligonucleotide (ASO) hybridization assay was developed for the 167delT and 35delG mutations. Screening of 1012 anonymous Ashkenazi Jewish individuals from the New York Metropolitan area revealed carrier frequencies for 167delT and 35delG of 3.96% (95% CI: 2.75–5.15%) and 0.69% (95% CI: 0.18–1.20%), respectively. This sensitive, specific, and relatively inexpensive method can reliably identify affected newborns and patients with NSRD as well as facilitate carrier screening for Connexin 26 deafness in the Ashkenazi Jewish community.