A cost-effectiveness analysis of pre-pregnancy genetic screening for deafness: an empirical study in China.

Objectives: This research aims to assess the effectiveness and cost-effectiveness of pre-pregnancy deafness screening policies. Methods: Married couples from Shanghai, Beijing, and Suzhou in China were enrolled. We conducted high-throughput, pre-pregnancy genetic screenings for deafness in women and their partners. We compared the cost-effectiveness of deafness genetic screening with the status quo. The two-step screening (wife then partner) and following treatments and interventions were included in the decision tree model. We conducted a cost-effectiveness analysis based on the decrease in deaf newborns, healthy newborn births, and cost-utility analysis of pre-pregnancy deafness genetic screening separately. Cost, utility, and probability data used in the three models were collected from a survey combined with literature and expert consultants. A 5% discount rate and a series of one-way sensitivity analyses along with a Monte Carlo simulation were used to test the reliability of this research. Results: Between Jan 1, 2019, and Dec 31, 2021, we recruited 6,200 females and 540 male spouses from community health service centers in Shanghai, Beijing, and Suzhou. The incremental cost-effectiveness ratio (ICER) for reducing deaf newborn births was USD 32,656 per case and USD 1,203,926 per case for increasing one healthy newborn birth. This gap exists because of the overall decrease of newborn births. From the perspective of the whole society, deafness genetic screening is not cost-effective for reducing the overall quality-adjusted life years (QALY) in the population. Discussion: Pre-pregnancy genetic testing is effective in decreasing the occurrence of congenital deafness. It is a cost-saving measure when compared with the costs of future medical expenditure and income loss for the affected families. However, such screening and preventive avoidance of pregnancy will decrease the population size and QALY. Only post-screening ART with PGT was shown to increase the birth of healthy newborns. Focusing on key groups such as premature births or consanguineous couples may improve the societal effects of screening.

Genetic etiology of hearing loss in Iran.

Hearing loss (HL) is an etiologically heterogeneous disorder that affects around 5% of the world's population. There has been an exponential increase in the identification of genes and variants responsible for hereditary HL over recent years. Iran, a country located in the Middle East, has a high prevalence of consanguineous marriages, so heterogeneous diseases such as HL are more common. Comprehensive studies using different strategies from linkage analysis to next-generation sequencing, especially exome-sequencing, have achieved significant success in identifying possible pathogens in deaf Iranian families. About 12% of non-syndromic autosomal recessive HL genes investigated to date, were first identified in families from Iran. Variations of 56 genes have been observed in families with NSHL in Iran. Variants in GJB2, SLC26A4, MYO15A, MYO7A, CDH23, and TMC1 account for 16.5%, 16.25%, 13.5%, 9.35%, 6.9% and 4.92%, cases of NSHL, respectively. In summary, there are also different diagnostic rates between studies conducted in Iran. In the comprehensive investigations conducted by the Genetic Research Center of the University of Social Welfare and Rehabilitation Sciences over the past 20 years, the overall diagnosis rate is about 80% while there are other studies with lower diagnostic rates which could reflect differences in project designs, sampling, and accuracy and validity of the methods used. Furthermore, there are several syndromic HHLs in Iran including, Waardenburg syndrome, BOR syndrome, Brown-Vialetto-Van Laere syndrome, Wolfram syndrome, among which Pendred and Usher syndromes are well-studied. These results are of importance for further investigation and elucidation of the molecular basis of HHL in Iran.

The genetic etiology of hearing loss in Japan revealed by the social health insurance-based genetic testing of 10K patients.

Etiological studies have shown genetic disorders to be a major cause of sensorineural hearing loss, but there are a limited number of comprehensive etiological reports based on genetic analysis. In the present study, the same platform using a diagnostic DNA panel carrying 63 deafness genes and the same filtering algorithm were applied to 10,047 samples obtained from social health insurance-based genetic testing of hearing loss. The most remarkable result obtained in this comprehensive study was that the data first clarified the genetic epidemiology from congenital/early-onset deafness to late-onset hearing loss. The overall diagnostic rate was 38.8%, with the rate differing for each age group; 48.6% for the congenital/early-onset group (~5y.o.), 33.5% for the juvenile/young adult-onset group, and 18.0% for the 40+ y.o. group. Interestingly, each group showed a different kind of causative gene. With regard to the mutational spectra, there are certain recurrent variants that may be due to founder effects or hot spots. A series of haplotype studies have shown many recurrent variants are due to founder effects, which is compatible with human migration. It should be noted that, regardless of differences in the mutational spectrum, the clinical characteristics caused by particular genes can be considered universal. This comprehensive review clarified the detailed clinical characteristics (onset age, severity, progressiveness, etc.) of hearing loss caused by each gene, and will provide useful information for future clinical application, including genetic counseling and selection of appropriate interventions.

Enhancing Genetic Medicine: Rapid and Cost-Effective Molecular Diagnosis for a GJB2 Founder Mutation for Hearing Impairment in Ghana.

In Ghana, gap-junction protein ß 2 (GJB2) variants account for about 25.9% of familial hearing impairment (HI) cases. The GJB2-p.Arg143Trp (NM_004004.6:c.427C>T/OMIM: 121011.0009/rs80338948) variant remains the most frequent variant associated with congenital HI in Ghana, but has not yet been investigated in clinical practice. We therefore sought to design a rapid and cost-effective test to detect this variant. We sampled 20 hearing-impaired and 10 normal hearing family members from 8 families segregating autosomal recessive non syndromic HI. In addition, a total of 111 unrelated isolated individuals with HI were selected, as well as 50 normal hearing control participants. A restriction fragment length polymorphism (RFLP) test was designed, using the restriction enzyme NciI optimized and validated with Sanger sequencing, for rapid genotyping of the common GJB2-p.Arg143Trp variant. All hearing-impaired participants from 7/8 families were homozygous positive for the GJB2-p.Arg143Trp mutation using the NciI-RFLP test, which was confirmed with Sanger sequencing. The investigation of 111 individuals with isolated non-syndromic HI that were previously Sanger sequenced found that the sensitivity of the GJB2-p.Arg143Trp NciI-RFLP testing was 100%. All the 50 control subjects with normal hearing were found to be negative for the variant. Although the test is extremely valuable, it is not 100% specific because it cannot differentiate between other mutations at the recognition site of the restriction enzyme. The GJB2-p.Arg143Trp NciI-RFLP-based diagnostic test had a high sensitivity for genotyping the most common GJB2 pathogenic and founder variant (p.Arg143Trp) within the Ghanaian populations. We recommend the adoption and implementation of this test for hearing impairment genetic clinical investigations to complement the newborn hearing screening program in Ghana. The present study is a practical case scenario of enhancing genetic medicine in Africa.

Social Health Insurance-Based Simultaneous Screening for 154 Mutations in 19 Deafness Genes Efficiently Identified Causative Mutations in Japanese Hearing Loss Patients.

Sensorineural hearing loss is one of the most common neurosensory disorders in humans. The incidence of SNHL is estimated to be 1 in 500-1000 newborns. In more than half of these patients, the hearing loss is associated with genetic causes. In Japan, genetic testing for the patients with SNHL using the Invader assay to screen for 46 mutations in 13 deafness genes was approved by the Ministry of Health, Labour and Welfare for inclusion in social health insurance coverage in 2012. Furthermore, from August 2015, this genetic testing has been expanded to screen for 154 mutations in 19 deafness genes using targeted genomic enrichment with massively parallel DNA sequencing combined with the Invader assay and TaqMan genotyping. For this study we analyzed 717 unrelated Japanese hearing loss patients. The total allele frequency of 154 mutations in 19 deafness genes was 32.64% (468/1434) and the total numbers of cases associated with at least one mutation was 44.07% (316/717). Among these, we were able to diagnose 212 (30%) patients, indicating that the present screening could efficiently identify causative mutations in hearing loss patients. It is noteworthy that 27 patients (3.8%) had coexistent multiple mutations in different genes. Five of these 27 patients (0.7%, 5/717 overall) were diagnosed with genetic hearing loss affected by concomitant with responsible mutations in more than two different genes. For patients identified with multiple mutations in different genes, it is necessary to consider that several genes might have an impact on their phenotypes.

Precision assessment of public attitudes toward genetic testing.

Public attitudes toward genetic testing are largely unknown. Furthermore, as medical practices vary widely among different regions around the world due to differences in cultural, sociopolitical, and economical environments, people from different regions may have drastically different attitudes. Even for the same individual, the attitude may vary depending on the purpose and type of genetic testing and the disorder to be tested for. It seems to me what is called for is a "precision" approach to gauging people's attitude toward genetic testing. In the current issue of the American Journal of Medical Genetics: Part A, Fu et al. reported a carefully designed study that began to fill this gap, although more work need to be done for different disorders and among other populations. © 2016 Wiley Periodicals, Inc.

A Rapid, Cost-Effective Method to Prepare Recombinant Adeno-Associated Virus for Efficient Gene Transfer to the Developing Mouse Inner Ear.

There is keen interest to define gene therapies aimed at restoration of auditory and vestibular function in the diseased or damaged mammalian inner ear. A persistent limitation of regenerative medical strategies that seek to correct or modify gene expression in the sensory epithelia of the inner ear involves efficacious delivery of a therapeutic genetic construct. Our approach is to define methodologies that enable fetal gene transfer to the developing mammalian inner ear in an effort to correct defective gene expression during formation of the sensory epithelia or during early postnatal life. Conceptually, the goal is to atraumatically introduce the genetic construct into the otocyst-staged mouse inner ear and transfect otic progenitors that give rise to sensory hair cells and supporting cells. Our long-term goal is to define therapeutic interventions for congenital deafness and balance disorders with the expectation that the approach may also be exploited for therapeutic intervention postnatally.In the inaugural volume of this series, we introduced electroporation-mediated gene transfer to the developing mouse inner ear that encompassed our mouse survival surgery and transuterine microinjection protocols (Brigande et al., Methods Mol Biol 493:125-139, 2009). In this chapter, we first briefly update our use of sodium pentobarbital anesthesia, our preferred anesthetic for mouse ventral laparotomy, in light of its rapidly escalating cost. Next, we define a rapid, cost-effective method to produce recombinant adeno-associated virus (rAAV) for efficient gene transfer to the developing mouse inner ear. Our immediate goal is to provide a genetic toolkit that will permit the definition and validation of gene therapies in mouse models of human deafness and balance disorders.

Noninvasive prenatal testing for autosomal recessive conditions by maternal plasma sequencing in a case of congenital deafness.

PURPOSE: The goals of our study were to develop a noninvasive prenatal test for autosomal recessive monogenic conditions and to prove its overall feasibility and potential for clinical integration. METHODS: We recruited a pregnant woman and her spouse, who had a proband child suffering from congenital deafness, and obtained the target-region sequencing data from a semicustom array that used genomic and maternal plasma DNA from three generations of this family. A haplotype-assisted strategy was developed to detect whether the fetus inherited the pathogenic mutations in the causative gene, GJB2. The parental haplotype was constructed using a trio strategy through two different processes, namely, the grandparent-assisted haplotype phasing process and the proband-assisted haplotype phasing process. The fetal haplotype was deduced afterward based on both the maternal plasma sequencing data and the parental haplotype. RESULTS: The accuracy levels of paternal and maternal haplotypes obtained by grandparent-assisted haplotype phasing were 99.01 and 97.36%, respectively, and the proband-assisted haplotype phasing process yielded slightly lower accuracies of 98.73 and 96.79%, respectively. Fetal inheritance of the pathogenic gene was deduced correctly in both processes. CONCLUSION: Our study indicates that the strategy of haplotype-based noninvasive prenatal testing for monogenic conditions has potential applications in clinical practice.

Maternally inherited diabetes and deafness (MIDD): diagnosis and management.

Maternally inherited diabetes with deafness is rare diabetes caused by a mitochondrial DNA defect. 85% of cases are associated with m.3243A>G mutation. It is important to diagnose this form of diabetes because of the unique management issues and associated comorbidities. A very strong family history of diabetes, deafness and presence of retinal dystrophy should prompt an investigation for MIDD. Microvascular complications out of keeping with duration of diabetes are another clue to the diagnosis. Retinal and renal manifestations of mitochondrial disease may be confused for diabetic complications. Glutamic acid decarboxylase (GAD) autoantibody negativity in a nonobese diabetic is another clue. Cardiac conduction defects and GDM may also raise suspicion as to the diagnosis. Recognizing this etiology of DM should promote family screening, genetic counseling, screening of associated comorbidities, avoidance of metformin, and cautious use of statins. We report a 77 years old lady with MIDD who was being followed up as insulin requiring type 2 diabetes. We then identified 5 more patients with MIDD in the same clinic. They all had A3243 mutation with characteristic clinical presentation. The pharmacological approaches discussed in the paper are unlikely to work in these patients as they were diagnosed late.

Diagnostic application of targeted resequencing for familial nonsyndromic hearing loss.

Identification of causative genes for hereditary nonsyndromic hearing loss (NSHL) is important to decide treatment modalities and to counsel the patients. Due to the genetic heterogeneity in sensorineural genetic disorders, the high-throughput method can be adapted for the efficient diagnosis. To this end, we designed a new diagnostic pipeline to screen all the reported candidate genes for NSHL. For validation of the diagnostic pipeline, we focused upon familial NSHL cases that are most likely to be genetic, rather than to be infectious or environmental. Among the 32 familial NSHL cases, we were able to make a molecular genetic diagnosis from 12 probands (37.5%) in the first stage by their clinical features, characteristic inheritance pattern and further candidate gene sequencing of GJB2, SLC26A4, POU3F4 or mitochondrial DNA. Next we applied targeted resequencing on 80 NSHL genes in the remaining 20 probands. Each proband carried 4.8 variants that were not synonymous and had the occurring frequency of less than three among the 20 probands. These variants were then filtered out with the inheritance pattern of the family, allele frequency in normal hearing 80 control subjects, clinical features. Finally NSHL-causing candidate mutations were identified in 13(65%) of the 20 probands of multiplex families, bringing the total solve rate (or detection rate) in our familial cases to be 78.1% (25/32) Damaging mutations discovered by the targeted resequencing were distributed in nine genes such as WFS1, COCH, EYA4, MYO6, GJB3, COL11A2, OTOF, STRC and MYO3A, most of which were private. Despite the advent of whole genome and whole exome sequencing, we propose targeted resequencing and filtering strategy as a screening and diagnostic tool at least for familial NSHL to find mutations based upon its efficacy and cost-effectiveness.

A low-cost exon capture method suitable for large-scale screening of genetic deafness by the massively-parallel sequencing approach.

Current major barriers for using next-generation sequencing (NGS) technologies in genetic mutation screening on an epidemiological scale appear to be the high accuracy demanded by clinical applications and high per-sample cost. How to achieve high efficiency in enriching targeted disease genes while keeping a low cost/sample is a key technical hurdle to overcome. We validated a cDNA-probe-based approach for capturing exons of a group of genes known to cause deafness. Polymerase chain reaction amplicons were made from cDNA clones of the targeted genes and used as bait probes in hybridization for capturing human genomic DNA (gDNA) fragments. The cDNA library containing the clones of targeted genes provided a readily available, low-cost, and regenerable source for producing capture probes with standard molecular biology equipment. Captured gDNA fragments by our method were sequenced by the Illumina NGS platform. Results demonstrated that targeted exons captured by our approach achieved specificity, multiplexicity, uniformity, and depth of coverage suitable for accurate sequencing applications by the NGS systems. Reliable genotype calls for various homozygous and heterozygous mutations were achieved. The results were confirmed independently by conventional Sanger sequencing. The method validated here could be readily expanded to include all-known deafness genes for applications such as genetic hearing screening in newborns. The high coverage depth and cost benefits of the cDNA-probe-based exon capture approach may also facilitate widespread applications in clinical practices beyond screening mutations in deafness genes.

Ubiquitin ligases of the N-end rule pathway: assessment of mutations in UBR1 that cause the Johanson-Blizzard syndrome.

BACKGROUND: Johanson-Blizzard syndrome (JBS; OMIM 243800) is an autosomal recessive disorder that includes congenital exocrine pancreatic insufficiency, facial dysmorphism with the characteristic nasal wing hypoplasia, multiple malformations, and frequent mental retardation. Our previous work has shown that JBS is caused by mutations in human UBR1, which encodes one of the E3 ubiquitin ligases of the N-end rule pathway. The N-end rule relates the regulation of the in vivo half-life of a protein to the identity of its N-terminal residue. One class of degradation signals (degrons) recognized by UBR1 are destabilizing N-terminal residues of protein substrates. METHODOLOGY/PRINCIPAL FINDINGS: Most JBS-causing alterations of UBR1 are nonsense, frameshift or splice-site mutations that abolish UBR1 activity. We report here missense mutations of human UBR1 in patients with milder variants of JBS. These single-residue changes, including a previously reported missense mutation, involve positions in the RING-H2 and UBR domains of UBR1 that are conserved among eukaryotes. Taking advantage of this conservation, we constructed alleles of the yeast Saccharomyces cerevisiae UBR1 that were counterparts of missense JBS-UBR1 alleles. Among these yeast Ubr1 mutants, one of them (H160R) was inactive in yeast-based activity assays, the other one (Q1224E) had a detectable but weak activity, and the third one (V146L) exhibited a decreased but significant activity, in agreement with manifestations of JBS in the corresponding JBS patients. CONCLUSIONS/SIGNIFICANCE: These results, made possible by modeling defects of a human ubiquitin ligase in its yeast counterpart, verified and confirmed the relevance of specific missense UBR1 alleles to JBS, and suggested that a residual activity of a missense allele is causally associated with milder variants of JBS.

Easy, rapid, and cost-effective methods for identifying carriers of recurrent GJB2 mutations causing nonsyndromic hearing impairment in the Greek population.

A variety of techniques have been developed for screening the GJB2 gene for known and unknown mutations, especially the most common mutation in the Caucasian population, the c.35delG. Other mutations that have been so far characterized in the GJB2 gene seem to have different geographical distributions, and therefore there is an interest in identifying recurrent mutations specific for each population and developing easy and rapid screening techniques. Here we present easy screening protocols for already identified recurrent mutations in the Greek population. Developing easy, rapid, and cost-effective screening methods will facilitate the detection of GJB2 recurrent mutation carriers, at large, in the Greek population.

Using assessment of higher brain functions of children with GJB2-associated deafness and cochlear implants as a procedure to evaluate language development.

OBJECTIVE: While investigators have reported that patients with GJB2-associated deafness and cochlear implants have preferable language development, the mechanisms of this phenomenon remains unknown. The goal of the present study was to assess higher brain functions of patients with GJB2-related and GJB2-unrelated deafness as a method of evaluating language development. METHODS: Eight children with cochlear implants were subjected to genetic testing for GJB2 and underwent the Raven colored progressive matrices test, Rey's auditory verbal learning test, Rey's complex figure test, the standardized language test for aphasia, the picture vocabulary test, and the standardized comprehension test for abstract words. RESULTS: Three children were diagnosed with GJB2-related deafness, and five children were diagnosed with GJB2-unrelated deafness. All three GJB2-related cases demonstrated normal range higher brain functions and fair language development. By contrast, one GJB2-unrelated case showed a semantic disorder, another demonstrated a visual cognitive disorder with dyslexia, and another had attention deficit-hyperactivity disorder. CONCLUSIONS: Children with GJB2-unrelated deafness showed a high frequency of heterogeneous disorders that can affect proper language development. This difference between children with GJB2-related and GJB2-unrelated deafness may account for the improved language development in children with GJB2-related deafness and cochlear implants. Further, genetic diagnosis of the non-syndromic hearing loss represents a useful tool for the preoperative prediction of outcomes following a cochlear implant procedure.

Assessment of the genetic causes of recessive childhood non-syndromic deafness in the UK - implications for genetic testing.

Approximately one in 2000 children is born with a genetic hearing impairment, mostly inherited as a non-syndromic, autosomal recessive trait, for which more than 30 different genes have been identified. Previous studies have shown that one of these genes, connexin 26 (GJB2), accounts for 30-60% of such deafness, but the relative contribution of the many other genes is not known, especially in the outbred UK population. This lack of knowledge hampers the development of diagnostic genetic services for deafness. In an effort to determine the molecular aetiology of deafness in the population, 142 sib pairs with early-onset, non-syndromic hearing impairment were recruited. Those in whom deafness could not be attributed to GJB2 mutations were investigated further for other mapped genes. The genetic basis of 55 cases (38.7%) was established, 33.1% being due to mutations in the GJB2 gene and 3.5% due to mutations in SLC26A4. None of the remaining 26 loci investigated made a significant contribution to deafness in a Caucasian population. We suggest that screening the GJB2 and SLC26A4 genes should form the basis of any genetic testing programme for childhood deafness and highlight a number of important issues for consideration and future work.

[Psychosocial characteristics of deaf people: evaluation of data from a special outpatient clinic for the deaf]. / Psychosoziale Merkmale bei Gehörlosen Daten aus einer Spezialambulanz für Gehörlose.

In this publication, data from a special outpatient clinic for deaf patients in a general hospital are presented. All members of the treatment team have competency in sign language. From the patients who consecutively attended the outpatient clinic, 352 were investigated for medical and psychosocial problems. In social contacts, there is a strong orientation towards other deaf people, and communication is mainly based on sign language. Of the deaf patients, 85% of their partners are also deaf, whereas only 10.1% of children of the deaf group are also deaf. The prevalence of selected psychiatric disorders (ICD 10 F1, F2, F3, F4, F6) in deaf people was found to be similar to that in hearing populations, with the exception of somatoform disorders, which seem to be more frequent in the deaf. Deaf people also more often present with somatic and other complaints such as nervousness, anxiety, and stress. With specific outpatient clinics for the deaf in which members of the therapeutic team are competent in sign language, access to health services is equally possible for deaf people.

Multiplex detection of common mutations in the Connexin-26 gene.

Hearing impairment that results from inherited genetic defects occurs in approximately 1/2,000 live births. Mutations in the Connexin-26 gene have been shown to be a major contributor to prelingual, nonsyndromic, autosomal recessive deafness in many populations. The most common mutations in this gene are 35delG, 167delT, 235delC, M34T, and W77X. We describe a nonisotopic, single-tube, polymerase chain reaction (PCR) multiplex system for the detection of these common mutations. The method presented is reliable, simple, and low in cost.