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1.
Eur J Med Genet ; : 104951, 2024 Jun 05.
Article En | MEDLINE | ID: mdl-38848991

The International Rare Diseases Research Consortium (IRDiRC) Diagnostic Scientific Committee (DSC) is charged with discussion and contribution to progress on diagnostic aspects of the IRDiRC core mission. Specifically, IRDiRC goals include timely diagnosis, use of globally coordinated diagnostic pipelines, and assessing the impact of rare diseases on affected individuals. As part of this mission, the DSC endeavored to create a list of research priorities to achieve these goals. We present a discussion of those priorities along with aspects of current, global rare disease needs and opportunities that support our prioritization. In support of this discussion, we also provide clinical vignettes illustrating real-world examples of diagnostic challenges.

2.
Lancet Reg Health Eur ; 37: 100783, 2024 Feb.
Article En | MEDLINE | ID: mdl-38169941

Despite general advancements in population health indicators and universal health coverage, people living with rare diseases and their families still experience considerable unmet needs, including prolonged diagnostic journeys, limited treatment options, and a huge psychosocial burden due to the lack of coordinated, integrated care. Attainment of universal health coverage for rare diseases is dependent on fundamentally different health determinants and demands for different solutions. This involves consolidating expertise through Centers of Excellence, establishing efficient care pathways, fostering extensive collaboration at European and global levels in research and healthcare, and putting patients at the center of care. Furthermore, development of specific indicators and coding systems is crucial for monitoring progress. Only in this way Europe can strive towards a future where people living with rare diseases receive the same level of equitable, safe, high-quality healthcare as other members of the society, in alignment with the overarching goal of leaving no one behind.

3.
Clin Chem Lab Med ; 61(2): 224-233, 2023 01 27.
Article En | MEDLINE | ID: mdl-36409605

The background to this debate is now well-known: an EU policy decision to tighten controls on the devices and diagnostics sector led to the adoption of a regulation in 2017 with a schedule for implementation over coming years - a timetable extended still further by last-minute legislation in early 2022, to provide the sector and regulators with more time to adapt to the changes. Discussions among experts organised in April by the European Alliance for Personalized Medicine (EAPM) exposed continuing challenges that cannot be fully resolved by the recent deferral of implementation deadlines. One salient problem is that there is little awareness of the In Vitro Diagnostic Regulation (IVDR) across Europe, and only limited awareness of the different structures of national systems involved in implementing IVDR, with consequent risks for patient and consumer access to in vitro diagnostics (IVDs). The tentative conclusion from these consultations is that despite a will across the sector to seek workable solutions, the obstacles remain formidable, and the potential solutions so far proposed remain more a matter of aspirations than of clear pathways.


Precision Medicine , Humans , Europe
4.
Orphanet J Rare Dis ; 17(1): 441, 2022 12 19.
Article En | MEDLINE | ID: mdl-36536417

People living with rare diseases (PLWRD) still face huge unmet needs, in part due to the fact that care systems are not sufficiently aligned with their needs and healthcare workforce (HWF) along their care pathways lacks competencies to efficiently tackle rare disease-specific challenges. Level of rare disease knowledge and awareness among the current and future HWF is insufficient. In recent years, many educational resources on rare diseases have been developed, however, awareness of these resources is still limited and rare disease education is still not sufficiently taken into account by some crucial stakeholders as academia and professional organizations. Therefore, there is a need to fundamentally rethink rare disease education and HWF development across the whole spectrum from students to generalists, specialists and experts, to engage and empower PLWRD, their families and advocates, and to work towards a common coherent and complementary strategy on rare disease education and training in Europe and beyond. Special consideration should be also given to the role of nurse coordinators in care coordination, interprofessional training for integrated multidisciplinary care, patient and family-centered education, opportunities given by digital learning and fostering of social accountability to enforce the focus on socially-vulnerable groups such as PLWRD. The strategy has to be developed and implemented by multiple rare disease education and training providers: universities, medical and nursing schools and their associations, professional organizations, European Reference Networks, patient organizations, other organizations and institutions dedicated to rare diseases and rare cancers, authorities and policy bodies.


Rare Diseases , Humans , Europe
5.
Healthcare (Basel) ; 10(9)2022 Aug 23.
Article En | MEDLINE | ID: mdl-36141212

The delicate balance of funding research and development of treatments for rare disease is only imperfectly achieved in Europe, and even the current provisional equilibrium is under a new threat from well-intentioned policy changes now in prospect that could-in addition to the intrinsic complexities of research-reduce the incentives on which commercial activity in this area is dependent. The European Union review of its pharmaceutical legislation, for which proposals are scheduled to appear before the end of 2022, envisages adjusting the decade-old incentives to meet objectives that are more precisely targeted. However, researchers, physicians, patients and industry have expressed concerns that ill-considered modifications could have unintended consequences in disrupting the current balance and could reduce rather than increase the flow of innovative treatments for rare diseases.

6.
J Multidiscip Healthc ; 15: 553-566, 2022.
Article En | MEDLINE | ID: mdl-35387391

More than 650 inherited metabolic diseases may present with epilepsy or seizures. These diseases are often multisystem, life-long and induce complex needs of patients and families. Multidisciplinary care involves all stages of disease management: diagnostics, specific or symptomatic, acute and chronic treatments, and integrated care that takes into account not only medical, but also manifold psychosocial, educational, vocational and other needs of patients and their caregivers. Care coordination is indispensable to ensure smooth transitions of care across life and disease stages, including management of emergencies, transition from pediatric to adult services and palliative care. Care pathways are highly diverse and have to find the right balance between highly specialized and locally provided services. While multidisciplinary teams consist of many professionals, a named supervising physician in a highly specialized healthcare setting and a care coordinator are highly important. As the greatest burden of care always falls onto the shoulders of patients and/or families, patient empowerment should be a part of every care pathway and include provision of required information, involvement into common decision-making, patient's and family's education, support for self-management, liaison with peer support groups and emotional/ psychological support. Due to the rarity and complexity of these diseases, sufficient expertise may not be available in a national healthcare system and cross-border services (virtual or physical) in the recently developed European Reference Networks should be ensured through the proper organization of referral systems in each EU and EEA country. Finally, digital technologies are particularly important in the provision of services for patients with rare diseases and can significantly increase the availability of highly specialized services and expertise.

7.
Genes (Basel) ; 13(3)2022 03 12.
Article En | MEDLINE | ID: mdl-35328062

Understanding the genetic architecture of metabolic epilepsies is of paramount importance, both to current clinical practice and for the identification of further research directions. The main goals of our study were to identify the scope of metabolic epilepsies and to investigate their clinical presentation, diagnostic approaches and treatments. The International Classification of Inherited Metabolic Disorders and IEMbase were used as a basis for the identification and classification of metabolic epilepsies. Six hundred metabolic epilepsies have been identified, accounting for as much as 37% of all currently described inherited metabolic diseases (IMD). Epilepsy is a particularly common symptom in disorders of energy metabolism, congenital disorders of glycosylation, neurotransmitter disorders, disorders of the synaptic vesicle cycle and some other IMDs. Seizures in metabolic epilepsies may present variably, and most of these disorders are complex and multisystem. Abnormalities in routine laboratory tests and/or metabolic testing may be identified in 70% of all metabolic epilepsies, but in many cases they are non-specific. In total, 111 metabolic epilepsies (18% of all) have specific treatments that may significantly change health outcomes if diagnosed in time. Although metabolic epilepsies comprise an important and significant group of disorders, their real scope and frequency may have been underestimated.


Epilepsy , Metabolic Diseases , Energy Metabolism , Epilepsy/diagnosis , Epilepsy/genetics , Glycosylation , Humans , Metabolic Diseases/diagnosis , Metabolic Diseases/genetics , Seizures/diagnosis , Seizures/genetics
8.
Article En | MEDLINE | ID: mdl-35162696

The potential for the use of real-world data (RWD) to generate real-world evidence (RWE) that can inform clinical decision-making and health policy is increasingly recognized, albeit with hesitancy in some circles. If used appropriately, the rapidly expanding wealth of health data could improve healthcare research, delivery of care, and patient outcomes. However, this depends on two key factors: (1) building structures that increase the confidence and willingness of European Union (EU) citizens to permit the collection and use of their data, and (2) development of EU health policy to support and shape data collection infrastructures, methodologies, transmission, and use. The great potential for use of RWE in healthcare improvement merits careful exploration of the drivers of, and challenges preventing, efficient RWD curation. Literature-based research was performed to identify relevant themes and discussion topics for two sets of expert panels, organized by the European Alliance for Personalised Medicine. These expert panels discussed steps that would enable a gradual but steady growth in the quantity, quality, and beneficial deployment of RWE. Participants were selected to provide insight based on their professional medical, economic, patient, industry, or governmental experience. Here, we propose a framework that addresses public trust and access to data, cross-border governance, alignment of evidence frameworks, and demonstrable improvements in healthcare decisions. We also discuss key case studies that support these recommendations, in accordance with the discussions at the expert panels.


Delivery of Health Care , Trust , Data Collection , Health Policy , Health Services Research , Humans
11.
J Community Genet ; 12(2): 217-229, 2021 Apr.
Article En | MEDLINE | ID: mdl-33733400

European Reference Networks (ERNs) were founded on the principle that many rare disease (RD) issues are pan-European and any single Member State cannot solve them alone. In 2021, ERNs are already in the deployment stage; however, their day-to-day functioning and realization of their potential are still severely hampered by many challenges, including issues in governance and regulation, lack of legal status, insufficient and unsustainable funding, lack of ERN integration into national systems, endangered collaboration with UK RD experts due to Brexit, insufficient exploitation of ERN potential in RD research, underappreciation of highly qualified human resources, problems with the involvement of patient representatives, and still unclear place of ERNs in the overall European RD and digital ecosystem. Bold and innovative solutions that must be taken to solve these challenges inevitably involve pan-European collaboration across several sectors and among multistakeholder RD communities and in many cases crucially rely on the constructive dialogue and coherent, united decisions of national and European authorities that are based on common EU values. Importantly, unresolved challenges may have a strong impact on the further sustainability of ERNs and their ability to realize full potential in addressing huge unmet needs of RD patients and their families.

12.
J Community Genet ; 12(2): 231-239, 2021 Apr.
Article En | MEDLINE | ID: mdl-33738760

Care pathways (CPW) are used worldwide to structure care processes within the patient-centered care concept. Rare diseases (RD), defined as those affecting less than 5 persons per 10,000 and including up to 10,000 different diseases, present unique challenges to CPW development due to their rarity and a large number of disease entities, chronic and frequently disabling nature, heterogeneous manifestation, multisystem involvement, and complexity in diagnostics and treatment. However, failure to develop RD CPWs eventually leads to long diagnostic odysseys, limited and unequal access to RD treatments, and a huge burden of complex care coordination that lies on the shoulders of patients and their families, imposing many personal, professional and social life difficulties, and diminishing their quality of life. In the development of RD CPW, there is a need to ensure smooth horizontal and vertical care integration, multiple transitions, and long-term care coordination across many geographically distant care providers and to find a fine balance between centralized expertise-based, complex, highly specialized services and possibilities for local care provision, patient empowerment and self-management, and digital healthcare. Established in 2017, European Reference Networks may have a high added value through an increase in accessibility and quality of services, economies of scale, scope and speed in the development of lacking evidence-based, educational and other resources for RD CPW, and speeding up innovation development and translation into RD CPW. However, their full benefits may only be reaped through a pan-European collaboration, universal acceptance of common European values and open-mindedness for sometimes disruptive innovation in the provision of healthcare across all Member States of the European Union.

13.
Clin Nutr ; 39(11): 3385-3394, 2020 11.
Article En | MEDLINE | ID: mdl-32184025

BACKGROUND & AIMS: Nutritional impairments are highly frequent in pancreatic cancer even in the early stages and have a significant impact on outcomes. The aim of this prospective study was to investigate immune and nutritional impairments, their interrelations and impacts on outcomes in an unselected cohort of patients scheduled for pancreatoduodenectomy due to suspicion of pancreatic cancer. METHODS: All consecutive patients scheduled for pancreatoduodenectomy at Vilnius University Hospital Santaros Klinikos between January 2016 and November 2018 were recruited into the study according to the inclusion/exclusion criteria. Patients were randomly allocated into the groups of nutritional intervention with immunonutrition vs. control and stratified into the groups of pancreatic ductal adenocarcinoma (PDAC) vs. other pancreatic tumors. Nutritional evaluation included screening (NRS 2002), anthropometric measurements, bioelectrical impedance analysis and lumbar skeletal muscle index (LSMI). Inflammatory indicators were measured before and after surgery. Surgical outcomes were assessed 30 days postoperatively using Comprehensive Complication Index (CCI). RESULTS: Although increased nutritional risk was identified in 22.4% of patients, 41.4% were finally diagnosed with cachexia. While cachexia was predominantly diagnosed in underweight patients, sarcopenia was detected across all BMI categories and 11.7% of obese patients had sarcopenia. Decreased LSMI was identified in 52.5% of patients as compared to decreased phase angle in 39% of patients and decreased fat free mass index in only 3.4% of patients. Regression model indicate a large effect of nutritional indicators on CCI (R2 coefficient 71.1%). In comparison to patients with other pancreatic tumors, patients with PDAC had a characteristic pattern of increased systemic inflammation prior to surgery and decreased inflammation postoperatively (p = 0.02). CONCLUSIONS: A high rate of nutritional impairments was identified in our cohort of patients with early pancreatic cancer, including abnormal body composition phenotypes. They produced negative effects on postoperative outcomes. The highest diagnostic rates were obtained with LSMI measurement, while the highest value for prognostication was attained with the inclusion of multiple objective nutritional state indicators.


Carcinoma, Pancreatic Ductal/physiopathology , Nutritional Status , Pancreatic Neoplasms/physiopathology , Pancreaticoduodenectomy , Postoperative Complications/etiology , Aged , Anthropometry , Body Mass Index , Cachexia/epidemiology , Cachexia/etiology , Carcinoma, Pancreatic Ductal/complications , Carcinoma, Pancreatic Ductal/therapy , Dietary Supplements , Electric Impedance , Female , Humans , Lumbar Vertebrae/physiopathology , Male , Middle Aged , Nutrition Assessment , Nutrition Therapy/methods , Pancreatic Neoplasms/complications , Pancreatic Neoplasms/therapy , Perioperative Care/methods , Preoperative Period , Prospective Studies , Regression Analysis , Sarcopenia/epidemiology , Sarcopenia/etiology , Treatment Outcome
14.
Biomed Hub ; 5(2): 1-11, 2020.
Article En | MEDLINE | ID: mdl-33564657

Since developments are global in the healthcare arena, more should be done to align EU and other big markets' regulatory practices for rare disease patients. Notwithstanding efforts and cooperation between the US and EU aimed to harmonize their strategic plans in the field of orphan drugs, regulatory criteria and procedures to gain the designation, terms and classifications should be still harmonised. Aligning the criteria of prevalence and support to orphan medicines in the various jurisdictions internationally, would facilitate patient recruitment eventually at global level, so as to gain the data and the biological insights required to identify biomarkers and appropriate endpoints needed for progressing clinical development. A conducive regulatory environment can further support the development of medicines to treat rare diseases. Overall there is a need for joined-up regulatory process coordination. Better integration of regulatory pathways and better integration of regulatory systems, such as scientific tools and methods to generate evidence, would be helpful. There is a need to revise and agree the current frameworks to be improved which will take into account the considerations and challenges to diagnose and treat different rare diseases and improve quality of life. Deliberative processes with multi-stakeholders' involvement for reimbursement should be considered. This paper explores the successes and limitation of both the regulation and its implementation mechanisms in the current regulatory context, and suggests some improvements that could maximise its benefits and boost rare disease research even further.

15.
Biomed Hub ; 5(3): 1341-1363, 2020.
Article En | MEDLINE | ID: mdl-33564668

"A ship in the harbour is safe, but that is not what ships are built for," observed that sage 19th century philosopher William Shedd. In other words, technology of high potential is of little value if the potential is not exploited. As the shape of 2020 is increasingly defined by the coronavirus pandemic, digitalisation is like a ship loaded with technology that has a huge capacity for transforming mankind's combat against infectious disease. But it is still moored safely in harbour. Instead of sailing bravely into battle, it remains at the dockside, cowering from the storm beyond the breakwaters. Engineers and fitters constantly fine-tune it, and its officers and deckhands perfect their operating procedures, but that promise is unfulfilled, restrained by the hesitancy and indecision of officialdom. Out there, the seas of the pandemic are turbulent and uncharted, and it is impossible to know in advance everything of the other dangers that may lurk beyond those cloudy horizons. However, the more noble course is for orders to be given to complete the preparations, to cast off and set sail, and to join other vessels crewed by valiant healthcare workers and tireless researchers, already deeply engaged in a rescue mission for the whole of the human race. It is the destiny of digitalisation to navigate those oceans alongside other members of that task force, and the hour of destiny has arrived. This article focuses on the potential enablers and recommendation to maximise learnings during the era of COVID-19.

16.
Metab Brain Dis ; 33(6): 1781-1786, 2018 12.
Article En | MEDLINE | ID: mdl-30006695

Many inborn errors of metabolism may present with epilepsy or seizures, however, current scope of these diseases is unknown. Due to available precision medicine approaches in many inborn errors of metabolism and sophisticated traditional diagnostics, this group of disorders is of special relevance to clinicians. Besides, as current treatment is challenging and unsuccessful in more than 30% of all epilepsy patients, these diseases may provide valuable models for ictogenesis and epileptogenesis studies and potentially pave the ways to identification of novel treatments. The aim of this study was to elucidate genetic architecture of inborn errors of metabolism involving epilepsy or seizures and to evaluate their diagnostic approaches. After extensive search, 880 human genes were identified with a considerable part, 373 genes (42%), associated with inborn errors of metabolism. The most numerous group comprised disorders of energy metabolism (115, 31% of all inborn errors of metabolism). A substantial number of these diseases (26%, 97/373) have established specific treatments, therefore timely diagnosis comes as an obligation. Highly heterogenous, overlapping and non-specific phenotypes in most of inborn errors of metabolism presenting with epilepsy or seizures usually preclude phenotype-driven diagnostics. Besides, as traditional diagnostics involves a range of specialized metabolic tests with low diagnostic yields and is generally inefficient and lengthy, next-generation sequencing-based methods were proposed as a cost-efficient one-step way to shorten "diagnostic odyssey". Extensive list of 373 epilepsy- or seizures-associated inborn errors of metabolism genes may be of value in development of gene panels and as a tool for variants' filtration.


Epilepsy/etiology , Metabolism, Inborn Errors/complications , Seizures/etiology , Epilepsy/metabolism , Humans , Metabolism, Inborn Errors/metabolism , Seizures/metabolism
17.
J Appl Genet ; 58(4): 467-474, 2017 Nov.
Article En | MEDLINE | ID: mdl-28933030

Proper epigenetic regulation processes are crucial in the normal development of the human brain. An ever-increasing group of neurodevelopmental disorders due to derangements of epigenetic regulation involve both microdeletion and monogenic syndromes. Some of these syndromes have overlapping clinical phenotypes due to haploinsufficiency-sensitive genes involved in microdeletions. It was shown recently that the ZMYND11 gene has important functions in epigenetic regulation as an unconventional transcription co-repressor of highly expressed genes, possibly acting in the repression of cryptic transcription from gene bodies. The aim of our study was to compare the clinical phenotypes of patients with 10p15.3 deletions with the phenotypes of patients with loss-of-function ZMYND11 mutations. The results of our study further confirm that the ZMYND11 gene is the critical gene for the clinical phenotype of 10p15.3 microdeletion involving the terminal ~4 Mb of chromosome 10p. In addition, accumulating clinical data allow for further characterisation of this syndrome, including neurodevelopmental disorder, characteristic dysmorphic features and some other more frequent symptoms, such as behavioural disturbances, hypotonia, seizures, low birth weight, short stature in those older than 10 years of age, genitourinary malformations and recurrent infections.


Carrier Proteins/genetics , Chromosomes, Human, Pair 10/genetics , Intellectual Disability/genetics , Abnormalities, Multiple/genetics , Adolescent , Adult , Cell Cycle Proteins , Child , Child, Preschool , Chromosome Deletion , Co-Repressor Proteins , DNA-Binding Proteins , Epigenesis, Genetic/genetics , Female , Humans , Infant , Male , Middle Aged , Phenotype , Syndrome , Young Adult
18.
Eur J Med Genet ; 60(3): 154-158, 2017 Mar.
Article En | MEDLINE | ID: mdl-28089741

Aicardi-Goutières syndrome (AGS) is an inflammatory disorder belonging to the recently characterized group of type I interferonopathies. The most consistently affected tissues in AGS are the central nervous system and skin, but various organ systems and tissues have been reported to be affected, pointing to the systemic nature of the disease. Here we describe a patient with AGS due to a homozygous p.Arg114His mutation in the TREX1 gene. The histologically proven inflammatory myopathy in our patient expands the range of clinical features of AGS. Histological signs of muscle biopsies in the proband, and in two other AGS patients described earlier, are similar to those seen in various autoimmune myositises and could be ascribed to inapproapriate IFN I activation. In view of signs of possible mitochondrial damage in AGS, we propose that mitochondrial DNA could be a trigger of autoimmune responses in AGS.


Autoimmune Diseases of the Nervous System/genetics , Autoimmune Diseases of the Nervous System/pathology , Exodeoxyribonucleases/genetics , Interferon Type I/immunology , Mitochondria/pathology , Myositis/pathology , Nervous System Malformations/genetics , Nervous System Malformations/pathology , Phosphoproteins/genetics , Base Sequence , Child , DNA, Mitochondrial/genetics , Female , Genetic Predisposition to Disease , Humans , Mitochondria/genetics , Sequence Analysis, DNA
19.
Ophthalmic Genet ; 38(4): 383-386, 2017.
Article En | MEDLINE | ID: mdl-27880066

BACKGROUND: Blepharophimosis is a fixed reduction in the vertical distance between the upper and lower eyelids with short palpebral fissures. It is a rare facial malformation and is considered an important diagnostic feature in dysmorphic analysis. It is likely that many patients with blepharophimosis-mental retardation syndrome have submicroscopic chromosomal rearrangements, and the use of molecular karyotyping can narrow the known blepharophimosis-mental retardation-critical regions or clarify the effect of the haploinsufficiency of the involved genes on the phenotype. MATERIALS AND METHODS: A female patient presented with bilateral blepharophimosis, ptosis, epicanthus inversus, telecanthus, low-set and small ears, other minor anomalies, hypotonia and psychomotor developmental delay. Metabolic investigations and array CGH analysis were performed. The results of molecular karyotyping were confirmed by real-time PCR analysis. RESULTS: Molecular karyotyping revealed a 5.2 Mb deletion in the 10q22.1q22.3 region. Real-time PCR analysis of the proband and her parents confirmed the deletion in the proband and revealed its de novo origin. CONCLUSIONS: With ptosis, hypotonia, and developmental delay as the main diagnostic features of our patient, the effect of histone acetyltransferase-encoding KAT6B gene haploinsufficiency was suspected to have a significant role in determining the phenotype. Detailed clinical characterization of the patient provided additional information on the clinical manifestation of the 10q22 deletion.


Blepharophimosis/diagnosis , Blepharophimosis/genetics , Chromosome Deletion , Chromosomes, Human, Pair 10/genetics , Histone Acetyltransferases/genetics , Skin Abnormalities/diagnosis , Skin Abnormalities/genetics , Urogenital Abnormalities/diagnosis , Urogenital Abnormalities/genetics , Child, Preschool , Developmental Disabilities/diagnosis , Developmental Disabilities/genetics , Female , Humans , Intellectual Disability/diagnosis , Intellectual Disability/genetics , Karyotyping , Real-Time Polymerase Chain Reaction
20.
BMC Genet ; 17: 45, 2016 Feb 19.
Article En | MEDLINE | ID: mdl-26896187

BACKGROUND: Congenital hearing loss (CHL) is diagnosed in 1 - 2 newborns in 1000, genetic factors contribute to two thirds of CHL cases in industrialised countries. Mutations of the GJB2 gene located in the DFNB1 locus (13q11-12) are a major cause of CHL worldwide. The aim of this cross-sectional study was to assess the contribution of the DFNB1 locus containing the GJB2 and GJB6 genes in the development of early onset hearing loss in the affected group of participants, to determine the population-specific mutational profile and DFNB1-related HL burden in Lithuanian population. METHODS: Clinical data were obtained from a collection of 158 affected participants (146 unrelated probands) with early onset non-syndromic HL. GJB2 and GJB6 gene sequencing and GJB6 gene deletion testing were performed. The data of GJB2 and GJB6 gene sequencing in 98 participants in group of self-reported healthy Lithuanian inhabitants were analysed. Statistic summary, homogeneity tests, and logistic regression analysis were used for the assessment of genotype-phenotype correlation. RESULTS: Our findings show 57.5% of affected participants with two pathogenic GJB2 gene mutations identified. The most prevalent GJB2 mutations were c.35delG, p. (Gly12Valfs*2) (rs80338939) and c.313_326del14, p. (Lys105Glyfs*5) (rs111033253) with allele frequencies 64.7% and 28.3% respectively. GJB6 gene mutations were not identified in the affected group of participants. The statistical analysis revealed significant differences between GJB2(-) and GJB2(+) groups in disease severity (p = 0.001), and family history (p = 0.01). The probability of identification of GJB2 mutations in patients with various HL characteristics was estimated. The carrier rate of GJB2 gene mutations - 7.1% (~1 in 14) was identified in the group of healthy participants and a high frequency of GJB2-related hearing loss was estimated in our population. DISCUSSION: The results show a very high proportion of GJB2-positive individuals in the research group affected with sensorineural HL. The allele frequency of c.35delG mutation (64.7 %) is consistent with many previously published studies in groups of affected individuals of Caucasian populations. The high frequency of the c.313_326del14 (28.3 % of pathogenic alleles) mutation in affected group of participants was an unexpected finding in our study suggesting not only a high frequency of carriers of this mutation in our population but also its possible origin in Lithuanian ancestors. The high frequency of carriers of the c.313_326del14 mutation in the entire Lithuanian population is supported by it being identified twice in the ethnic Lithuanian group of healthy participants (a frequency 2.0 % of carriers in the study group). CONCLUSION: Analysis of the allele frequency of GJB2 gene mutations revealed a high proportion of c. 313_326del14 (rs111033253) mutations in the GJB2-positive group suggesting its possible origin in Lithuanian forebears. The high frequency of carriers of GJB2 gene mutations in the group of healthy participants corresponds to the substantial frequency of GJB2-associated HL in Lithuania. The observations of the study indicate the significant contribution of GJB2 gene mutations to the pathogenesis of the disorder in the Lithuanian population and will contribute to introducing principles to predict the characteristics of the disease in patients.


Connexins/genetics , Hearing Loss, Sensorineural/genetics , White People/genetics , Alleles , Child, Preschool , Connexin 26 , Cross-Sectional Studies , Female , Gene Deletion , Gene Frequency , Genetic Association Studies , Genetic Loci , Hearing Loss, Sensorineural/diagnosis , Humans , Lithuania , Logistic Models , Male , Mutation , Sequence Analysis, DNA
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