1.Bali Chronic Constipation Roundtable Report: Chronic ConstipationManagement in Asia
Yi Ping REN ; Wah Loong CHAN ; Kee Huat CHUAH ; Yong Sung KIM ; Atsushi NAKAJIMA ; Sanjiv MAHADEVA ; Yeong Yeh LEE ; Andrew S B CHUA ; Tao BAI ; Ari Fahrial SYAM ; Chien-Lin CHEN ; Ching-Liang LU ; M. Masudur RAHMAN ; Tanisa PATCHARATRAKUL ; Victoria Ping Y TAN ; Dao Viet HANG ; Xiaohua HOU ; Yinglian XIAO ; Justin WU ; Uday C GHOSHAL ; Hidekazu SUZUKI ; Sutep GONLACHANVIT ; Kewin T H SIAH
Journal of Neurogastroenterology and Motility 2026;32(1):109-128
Background/Aims:
Chronic constipation is prevalent yet under-diagnosed across Asia, compromising quality of life and burdening healthcare systems. Cultural stigma, varied diets, and limited access to standardized diagnostic tools delay timely care.
Methods:
The Bali Chronic Constipation Roundtable in November 2024, brought together experts from 11 Asian countries. The group reviewed epidemiological data, analyzed multinational questionnaire on clinical practice pattern, and conducted structured discussions to identify key barriers and propose region-specific recommendations.
Results:
Chronic constipation prevalence varies across Asia, ranging from 1.8% in India to 16.6% in Japan, with women and the elderly disproportionately affected. Under-reporting persists owing to cultural taboos and widespread self treatment with laxatives and traditional medications. Although the Rome IV criteria remains the global standard, they may not fully reflect Asian symptom profiles, and diagnosis is limited by scarce motility laboratories. First line therapies such as dietary-fiber optimization and osmotic laxatives are widely available, but newer pharmacotherapies (prucalopride, linaclotide, lubiprostone, and elobixibat) remain costly and unevenly accessible. Biofeedback for dyssynergic defecation is underutilized due to limited availability. Experts recommend expanded regional research on to refine diagnostic criteria, coupled with enhanced physician education and public awareness. They advocate accessibility to second-line and novel therapies that incorporate culturally attuned regional guidelines, and improved access to gastrointestinal motility testing.
Conclusions
The Bali Chronic Constipation Roundtable highlighted Asia’s need for region specific diagnostics and management. Addressing diagnostic and treatment gaps will improve outcomes, while ongoing researcher clinician policy collaboration must standardize guidelines, advance research, and ensure equitable care across Asia.
2.The Functional Study of Prostaglandin E2 via EP Receptor on Pacemaker Activity in Interstitial Cells of Cajal from Murine Colon
Hongyang GONG ; Han Yi JIAO ; Yuan CHANG ; Seok CHOI ; Chan Sik HONG ; Jae Yeoul JUN
Chonnam Medical Journal 2026;62(2):79-87
The interstitial cells of Cajal (ICC) generate spontaneous pacemaker activities responsible for producing slow waves in the gut smooth muscles. Prostaglandin E2 (PGE2 ) is one of the most important prostanoids in the gut, playing a crucial role in multiple physiological and pathological processes. Because information regarding the effects of PGE2 on colonic ICC is limited, we investigated the effects of PGE2 and its underlying signaling pathways in murine colonic ICC. Whole-cell patch-clamp recordings and reverse transcription polymerase chain reaction (RT-PCR) analyses were performed to evaluate the effects of PGE2 on mouse colonic ICC. PGE2 had a dual effect on pacemaker potential in the current-clamp mode. RT-PCR data suggested the expression of EP3 and EP4 receptors in colonic ICC. Low PGE2 concentrations induced membrane depolarization and generation of pacemaker activities. And this effect is mimicked by sulprostone (an EP3 agonist). The low PGE2 concentration-induced effect was inhibited by anoctamin-1 (ANO1) or a T-type Ca2+ channel blocker. Conversely, high PGE2 concentrations induced membrane hyperpolarization and blocked pacemaker potential generation. However, this inhibitory effect was blocked by an ATP-sensitive potassium (K ATP) channel blocker but not by other K+ channel blockers. Low concentrations of PGE2 activated EP3 receptors, leading to excitation of pacemaker activity through regulation of ANO1 and T-type Ca2+ channels in colonic ICC. In contrast, higher concentrations of PGE2 activated EP4 receptors and opened ATP-sensitive K+ channels, resulting in inhibition of pacemaker activity in colonic ICC.
3.Risk Assessment for Ramadan Fasting in People With Diabetes in Hospital-Based Diabetes Clinics Using the Updated 2026 IDF-DAR Risk Calculator
Raja Nurazni Raja Azwan ; Chin Voon Tong ; Lisa Mohamed Nor ; Marisa Khatijah Borhan ; Syarifah Syahirah Syed Abas ; Poh Shean Wong ; Ying Jie Tan ; Shartiyah Ismail ; Eunice Yi Chwen Lau ; Yueh Chien Kuan ; Noor Hafis Md Tob ; Shu Teng Chai ; Pei Lin Chan ; Xe Hui Lee ; Wei Wei Ng ; Jin Hui Ho ; Miza Hiryanti Zakaria ; Rabeah Md Zuki ; Wan Mohd Hafez Wan Hamzah ; Melissa Vergis ; Choon Peng Sun ; Vanusha Devaraja Pillai ; Chee Koon Low ; Shazatul Reza Mohd Redzuan ; Xin-Yi Ooi ; Siti Sanaa Wan Azman ; Deviga Lachumanan ; Saiful Shahrizal Shudim ; Zanariah Hussein
Journal of the ASEAN Federation of Endocrine Societies 2026;41(S1):42-43
Introduction:
The 2021 IDF-DAR risk calculator had been previously
evaluated in multiple studies and subsequently widely
accepted and applied in clinical practice as a practical
standardized tool for patient risk stratification. Recently
updated, the 2026 IDF-DAR Risk calculator enables a more individualized, evidence-related evaluation of patientrelated and disease-related risk factors, incorporating
modern diabetes technologies, including continuous
glucose monitoring (CGM), automated insulin delivery
(AID) systems, and advanced insulin formulations to
enhance risk stratification. This tool allows medical
professionals to tailor Ramadan practices based on overall
factors toward promoting safe fasting.
Methodology:
This prospective multicentre observational study recruited
adults with Type 1 and Type 2 diabetes attending public
hospitals nationwide. People with diabetes (PwD) intending
to perform Ramadan fasting were invited to participate
and assessed using the 2026 IDF-DAR Risk Calculator in
the 6-week pre-Ramadan period between 30th January and
19th March 2026.
Results:
A total of 458 PwD were evaluated and stratified into low
(15.7%), moderate (41%), and high risk (43.3%) categories.
Most participants had Type 2 diabetes (83.6%), with 60.3%
having a disease duration exceeding 10 years and 43%
exhibiting poor glycemic control (hemoglobin A1c >9%).
Insulin therapy was used by 76.4% of participants, including
two individuals with Type 1 diabetes using AID systems.
Most participants reported no recent hypoglycemia (76.4%),
81.0% performed glucose monitoring, and 3.3% used CGM.
Severe comorbidities were uncommon, with 1.1% having
unstable macrovascular disease and 4.4% advanced chronic
kidney disease (estimated glomerular filtration rate <30).
Notably, 72.2% received structured Ramadan education.
Conclusion
Majority of PwD attending tertiary diabetes clinics were
in the moderate- to high-risk category and intended to
fast despite medical advice against fasting in some cases.
Although most participants were on insulin therapy,
hypoglycemia was low in the pre-Ramadan period.
Integration of modern technologies, advanced insulin
therapies, and structured education may support safer
fasting practices.
Risk Assessment
;
Diabetes Mellitus
;
Hospitals
;
Fasting
4.Feasibility study of a domestic fully automated NAT system for blood screening in blood donors
Fenglan YAO ; Rui WANG ; Jinghui HU ; Hongwei GE ; Chan LENG ; Yi ZHA ; Zifu ZHAO ; Zhengmin LIU
Chinese Journal of Blood Transfusion 2025;38(7):941-949
Objective: To validate the analytical performance, operational performance, and process control measures of a domestic fully automatic nucleic acid testing (NAT) system, thereby ensuring an efficient and orderly blood screening workflow. Methods: The concordance rate and sensitivity of WanTag-Vortex Plus system were verified using WHO standard reference panels of HIV-1, HCV and HBV, while precision was assessed using weak positive samples of HIV-1, HCV and HBV. As for its operational performance evaluation, cross-contamination resistance was assessed using strong positive samples, and throughput and stress testing were conducted using negative samples. Reagent stability was verified using weak positive samples, and inter-system performance consistency was assessed using verification panels. In addition, the process control measures were verified using the laboratory quality control demand scale. Results: 1) Verification of concordance rate: The detection results of negative and positive samples of HIV-1, HCV and HBV by WanTag-Vortex Plus system were all consistent with expectations, and the concordance rate was 100%. 2) Precision verification: the repeatability and intermediate precision were extremely high, and the coefficient of variation was less than 5%. 3) Verification of analytical sensitivity: The detection limit of 95% for standard strains of HIV-1, HCV and HBV by WanTag-Vortex Plus system in our laboratory was consistent with the analytical sensitivity provided by reagent manufacturers. 4) Verification of cross-contamination resistance: Five strong positive samples and 87 negative samples were placed according to the actual working conditions and equipment operation design, and the test results were consistent with expectations, with no cross-contamination in the testing system. 5) Throughput and stress testing: Each system completed the individual donor-nucleic acid amplification testing (ID-NAT) of 276 samples in three batches within 12 hours, and successfully completed the ID-NAT test of 828 samples in three consecutive days. 6) Verification of reagent stability: After extreme storage (unsealed storage for 1 week with 4 freeze-thaw cycles), the reagents maintained 100% detection rate in the weak positive samples of HIV-1, HCV, and HBV, showing no significant differences from the control group (Kappa=1). 7) Verification of inter-system performance consistency: The system has stable operation performance, and the performance comparison results across the four devices were consistent (Kappa=1). 8) Process control measures: WanTag-Vortex Plus system software accurately controlled the equipment operation process with strict quality control measures, and correctly interpreted and safely reported the test results. Conclusion: The analytical and operational performance of the WanTag-Vortex Plus system complies with manufacturer design standards and essential laboratory workflow requirements. Integrated with laboratory information system (LIS), the system's control software meets standard process control requirements, yet requires further improvement.
5.Early predictors of rescue therapy and colectomy in acute severe ulcerative colitis.
Samuel Jun Ming LIM ; Kaina CHEN ; Yi Yuan TAN ; Shu Wen TAY ; Thomson Chong Teik LIM ; Ennaliza SALAZAR ; Webber Pak-Wo CHAN ; Malcolm Teck Kiang TAN
Singapore medical journal 2025;66(8):449-456
INTRODUCTION:
Acute severe ulcerative colitis (ASUC) is a significant cause of disease morbidity. One-third of patients with ASUC are steroid refractory. Rescue therapy may not successfully induce remission, necessitating colectomy. We aimed to identify predictors of rescue therapy and colectomy in ASUC assessed within 24 h of admission for early risk stratification.
METHODS:
We conducted a retrospective cohort study of 58 admissions for ASUC among 47 patients from August 2002 to January 2022. Serum biomarkers assessed were measured on admission. Primary outcomes were the need for rescue therapy during the same admission and colectomy within 1 year of admission.
RESULTS:
Rescue therapy (all with infliximab) was given in 20 (34.5%) of the admissions. Colectomy was done within 1 year for nine (15.5%) of the admissions. An elevated C-reactive protein (CRP) of >30 mg/L (relative risk [RR] 1.63), a CRP-albumin ratio of >0.85 (RR 1.63), and a composite factor of both CRP > 30 mg/L and age ≥60 years (RR 2.37) were significantly associated with the need for rescue therapy. Hypoalbuminaemia ≤ 25 g/L (RR 4.35) and the use of biologics at presentation (RR 1.54) were significantly associated with colectomy within 1 year of admission, while a CRP of ≥ 80 mg/L was a significant protective factor (RR 0.70).
CONCLUSION
Patients with ASUC who have elevated CRP or CRP-albumin ratio on admission should be considered at risk for steroid-refractory disease. Those with hypoalbuminaemia on admission and using biologics at presentation are more likely to require colectomy in the first year after admission for ASUC.
Humans
;
Colitis, Ulcerative/therapy*
;
Colectomy
;
Retrospective Studies
;
Male
;
Female
;
Middle Aged
;
Adult
;
C-Reactive Protein/metabolism*
;
Infliximab/therapeutic use*
;
Biomarkers/blood*
;
Acute Disease
;
Aged
;
Severity of Illness Index
;
Treatment Outcome
6.Environmental sustainability in healthcare: impacts of climate change, challenges and opportunities.
Ethan Yi-Peng KOH ; Wan Fen CHAN ; Hoon Chin Steven LIM ; Benita Kiat Tee TAN ; Cherlyn Tze-Mae ONG ; Prit Anand SINGH ; Michelle Bee Hua TAN ; Marcus Jin Hui SIM ; Li Wen ONG ; Helena TAN ; Seow Yen TAN ; Wesley Chik Han HUONG ; Jonathan SEAH ; Tiing Leong ANG ; Jo-Anne YEO
Singapore medical journal 2025;66(Suppl 1):S47-S56
Environmental damage affects many aspects of healthcare, from extreme weather events to evolving population disease. Singapore's healthcare sector has the world's second highest healthcare emissions per capita, hampering the nation's pledge to reduce emissions by 2030 and achieve net zero emissions by 2050. In this review, we provide an overview of the impact environmental damage has on healthcare, including facilities, supply chain and human health, and examine measures to address healthcare's impact on the environment. Utilising the 'R's of sustainability - rethinking, reducing/refusing, reusing/repurposing/reprocessing, repairing, recycling and research - we have summarised the opportunities and challenges across medical disciplines. Awareness and advocacy to adopt strategies at institutional and individual levels is needed to revolutionise our environmental footprint and improve healthcare sustainability. By leveraging evidence from ongoing trials and integrating sustainable practices, our healthcare system can remain resilient against environment-driven challenges and evolving healthcare demands while minimising further impacts of environmental destruction.
Humans
;
Climate Change
;
Delivery of Health Care
;
Singapore
;
Conservation of Natural Resources
;
Sustainable Development
;
Environment
7.Clinical and echocardiographic differences between rheumatic and degenerative mitral stenosis.
Ryan LEOW ; Ching-Hui SIA ; Tony Yi-Wei LI ; Meei Wah CHAN ; Eng How LIM ; Li Min Julia NG ; Tiong-Cheng YEO ; Kian-Keong POH ; Huay Cheem TAN ; William Kf KONG
Annals of the Academy of Medicine, Singapore 2025;54(4):227-234
INTRODUCTION:
Degenerative mitral stenosis (DMS) is frequently cited as increasing in prevalence in the developed world, although comparatively little is known about DMS in comparison to rheumatic mitral stenosis (RMS).
METHOD:
A retrospective observational study was conducted on 745 cases of native-valve mitral stenosis (MS) with median follow-up time of 7.25 years. Clinical and echocardiographic parameters were compared. Univariate and multivariate Cox regression analyses were performed for a composite of all-cause mortality and heart failure hospitalisation.
RESULTS:
Patients with DMS compared to RMS were older (age, mean ± standard deviation: 69.6 ± 12.3 versus [vs] 51.6 ± 14.3 years, respectively; P<0.001) and a greater proportion had medical comorbidities such as diabetes mellitus (78 [41.9%] vs 112 [20.0%], P<0.001). The proportion of cases of degenerative aetiology increased from 1.1% in 1991-1995 to 41.0% in 2016-2017. In multivariate analysis for the composite outcome, age (hazard ratio [HR] 95% confidence interval [CI] of 1.032 [1.020-1.044]; P<0.001), diabetes mellitus (HR 1.443, 95% CI 1.068-1.948; P=0.017), chronic kidney disease (HR 2.043, 95% CI 1.470-2.841; P<0.001) and pulmonary artery systolic pressure (HR 1.019, 95% CI 1.010- 1.027; P<0.001) demonstrated significant indepen-dent associations. The aetiology of MS was not independently associated with the composite outcome.
CONCLUSION
DMS is becoming an increasingly common cause of native-valve MS. Despite numerous clinical differences between RMS and DMS, the aetiology of MS did not independently influence a composite of mortality or heart failure hospitalisation.
Humans
;
Mitral Valve Stenosis/etiology*
;
Male
;
Female
;
Retrospective Studies
;
Middle Aged
;
Aged
;
Rheumatic Heart Disease/mortality*
;
Echocardiography
;
Hospitalization/statistics & numerical data*
;
Heart Failure/epidemiology*
;
Singapore/epidemiology*
;
Proportional Hazards Models
;
Diabetes Mellitus/epidemiology*
8.Evaluating the impact of relative dose intensity on efficacy of trastuzumab deruxtecan for metastatic breast cancer in the real-world clinical setting.
Han Yi LEE ; Vivianne SHIH ; Jack Junjie CHAN ; Shun Zi LIONG ; Ryan Shea Ying Cong TAN ; Jun MA ; Bernard Ji Guang CHUA ; Joshua Zhi Chien TAN ; Chuan Yaw LEE ; Wei Ling TEO ; Su-Ming TAN ; Phyu NITAR ; Yoon Sim YAP ; Mabel WONG ; Rebecca DENT ; Fuh Yong WONG ; Tira J TAN
Annals of the Academy of Medicine, Singapore 2025;54(8):458-466
INTRODUCTION:
Trastuzumab deruxtecan (T-DXd) has revolutionised treatment for metastatic breast cancer (MBC). While effective, its high cost and toxicities, such as fatigue and nausea, pose challenges.
METHOD:
Medical records from the Joint Breast Cancer Registry in Singapore were used to study MBC patients treated with T-DXd (February 2021-June 2024). This study was conducted to address whether reducing dose intensity and density may have an adverse effect on treatment outcomes.
RESULTS:
Eighty-seven MBC patients were treated with T-DXd, with a median age of 59 years. At the time of data cutoff, 32.1% of patients were still receiving T-DXd. Over half (54%) of the patients received treatment with an initial relative dose intensity (RDI) of <;85%. Overall median real-world progression-free survival (rwPFS) was 8.1 months. rwPFS was similar between RDI groups (<85%: 8.7 months, <85%: 8.1 months, P=0.62). However, human epidermal growth receptor 2 (HER2)-positive patients showed significantly better rwPFS outcomes compared to HER2-low patients (8.8 versus 2.5 months, P<0.001). Only 16% with central nervous system (CNS) involvement had CNS progressive disease on treatment. No significant progression-free survival (PFS) differences were found between patients with or without CNS disease, regardless of RDI groups. Five patients (5.7%) developed interstitial lung disease (ILD), with 3 (3.4%) having grade 3 events. Two required high-dose steroids and none were rechallenged after ILD. There were no fatalities.
CONCLUSION
Our study demonstrated that reduced dose intensity and density had no significant impact on rwPFS or treatment-related toxicities. Furthermore, only 5.7% of patients developed ILD. T-Dxd provided good control of CNS disease, with 82% of patients achieving CNS disease control.
Humans
;
Female
;
Breast Neoplasms/mortality*
;
Middle Aged
;
Trastuzumab/adverse effects*
;
Aged
;
Adult
;
Singapore/epidemiology*
;
Antineoplastic Agents, Immunological/adverse effects*
;
Camptothecin/adverse effects*
;
Immunoconjugates/adverse effects*
;
Retrospective Studies
;
Progression-Free Survival
;
Receptor, ErbB-2/metabolism*
;
Neoplasm Metastasis
;
Dose-Response Relationship, Drug
;
Treatment Outcome
;
Registries
9.Effect and mechanism of total paeony glycoside on airway remodeling in bronchial asthma
Yi-Jin ZHOU ; Xin-Lei TIAN ; Xing-Chan SHI ; Wen-Jie HU ; Shan ZHU
Medical Journal of Chinese People's Liberation Army 2025;50(4):467-474
Objective To investigate the effect of total paeony glycoside(TPG)on airway remodeling in bronchial asthma mice and its underlying mechanisms.Methods Forty-eight BALB/c mice were randomly divided into control group,model group,ovalbumin+budesonide group(OVA+BUD group),and OVA+TPG group,with 12 mice in each group.Except the control group,mice in other groups were sensitized by intraperitoneal injection of 10%OVA aluminum hydroxide suspension,and then stimulated by atomized inhalation of 1%OVA to establish mouse asthma model.One hour before each inhalation of OVA,mice in OVA+BUD group were atomized with 2 ml BUD suspension,and mice in OVA+TPG group were given 5 g/kg TPG by intragastric administration.Lung tissues and bronchoalveolar lavage fluid(BALF)of mice from each group were collected,and the pathological morphology of the lung tissues was detected by hematoxylin-eosin(HE)and periodic acid schiff(PAS)staining.Inflammatory cell counts[white blood cell(WBC),neutrophil(NEU),eosinophils(EOS),and leukomonocyte(LYM)]in BALF were detected by Wright-giemsa staining.The contents of inflammatory factors including tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β)and IL-6 in BALF were determined by ELISA.Airway remodeling proteins[fibronectin,α-smooth muscle actin(α-SMA),collagen Ⅰ]and NOD-like receptor protein 3(NLRP3)inflammasome-related proteins[NLRP3,cleaved caspase-1,apoptosis-associated speck-like protein(ASC)]levels were detected by Western blotting.Human bronchial smooth muscle cells(HBSMCs)were divided into control group(normal culture),transforming growth factor(TGF)-β1 group(culture medium containing 10 ng/ml TGF-β1),and TGF-β1+TPG group(culture medium containing 10 ng/ml TGF-β1 and 50 μg/ml TPG).Cell proliferation was detected by CCK-8 method,and Western blotting was used to detect the expression of airway remodeling proteins and NLRP3 inflammasome-related proteins.Results Compared with control group,model group exhibited increased infiltration of inflammatory cell in lung tissues,mucosal epithelium hyperplasia,narrowed bronchial lumen narrowed,tube wall thickened,increased cup cells and mucus secretion,and an elevated pathological score of lung injury(P<0.05);the number of inflammatory cells(WBC,NEU,EOS,and LYM)and the levels of inflammatory factors(TNF-α,IL-1β,and IL-6)in BALF were increased(P<0.05),and the expressions of fibronectin,α-SMA,collagen Ⅰ,NLRP3,cleaved caspase-1 and ASC were elevated(P<0.05).Compared with model group,BUD or TPG treatment effectively reduced asthma symptoms,improved lung histopathology injury,inhibited bronchial wall thickening,significantly reduced the number of inflammatory cells(WBC,NEU,EOS,and LYM)and the content of inflammatory factors(TNF-α,IL-1β,and IL-6)in BALF,and inhibited expression of fibronectin,α-SMA,collagen Ⅰ,NLRP3,cleaved caspase-1 and ASC(P<0.05).Compared with control group,the proliferation rate of HBSMCs was increased,and the protein expression levels of fibronectin,α-SMA,collagen Ⅰ,NLRP3,cleaved caspase-1 and ASC were increased in TGF-β1 group(P<0.05).Compared with TGF-β1 group,TPG treatment decreased cell proliferation and inhibited the protein expression of fibronectin,α-SMA,collagen Ⅰ,NLRP3,cleaved caspase-1 and ASC(P<0.05).Conclusion TPG may alleviate airway remodeling and asthma symptoms by decreasing the expression of airway remodeling-related proteins,inhibiting NLRP3 inflammasome activation,and reducing the inflammatory response.
10.Outcomes of identifying enlarged vestibular aqueduct (Mondini malformation) related gene mutation in Mongolian people
Jargalkhuu E ; Tserendulam B ; Maralgoo J ; Zaya M ; Enkhtuya B ; Ulzii B ; Ynjinlhkam E ; Chuluun-Erdene Ts ; Chen-Chi Wu ; Cheng-Yu Tsai ; Yin-Hung Lin ; Yi-Hsin Lin ; Yen-Hui Chan ; Chuan-Jen Hsu ; Wei-Chung Hsu ; Pei-Lung Chen
Mongolian Journal of Health Sciences 2025;87(3):8-15
Background:
Hearing loss (HL) is one of the most common sensory disorders,
affecting over 5-8% of the world's population. Approximately half of HL cases are
attributed to genetic factors. In hereditary deafness, about 75-80% is inherited
through autosomal recessive inheritance, and common pathogenic genes include
GJB2 and SLC26A4. Pathogenic variants in the SLC26A4gene are the leading
cause of hereditary hearing loss in humans, second only to the GJB2 gene. Variants in the SLC26A4gene cause hearing loss, which can be non-syndromic autosomal recessive deafness (DFNB4, OMIM #600791) associated with enlarged
vestibular aqueduct (EVA) or Pendred syndrome (Pendred, OMIM #605646).
DFNB4 is characterized by sensorineural hearing loss combined with EVA or less
common cochlear malformation defect. Pendred syndrome is characterized by bilateral sensorineural hearing loss with EVA and an iodine defect that can lead to
thyroid goiter. Currently, it is known that EVA is associated with variants in the
SLC26A4 gene and is a penetrant feature of SLC26A4-related HL. Predominant
mutations in these genes differ significantly across populations. For instance, predominant SLC26A4 mutations differ among populations, including p.T416P and
c.1001G>A in Caucasians, p.H723R in Japanese and Koreans, and c.919-2A>G
in Han Taiwanese and Han Chinese. On the other hand, there has been no study
of hearing loss related to SLC26A4 gene variants among Mongolians, which is the
basis of our research.
Aim:
We aimed to identify the characteristics of the SLC26A4 gene variants in
Mongolian people with Enlarged vestibular aqueduct and Mondini malformation.
Materials and Methods:
In 2022-2024, We included 13 people with hearing loss
and enlarged vestibular aqueduct, incomplete cochlea (1.5 turns of the cochlea
with cystic apex- incomplete partition type II- Mondini malformation) were examined by CT scan of the temporal bone in our study. WES (Whole exome sequencing) analysis was performed in the Genetics genetic-laboratory of the National
Taiwan University Hospital.
Results:
Genetic analysis revealed 26 confirmed pathogenic variants of bi-allelic
SLC26A4 gene of 8 different types in 13 cases, and c.919-2A>G variant was dominant with 46% (12/26) in allele frequency, and c.2027T>A (p.L676Q) variant 19%
(5/26), c.1318A>T(p.K440X) variant 11% (3/26), c.1229C>T (p.T410M) variant 8%
(2/26) ) , c.716T>A (p.V239D), c.281C>T (p.T94I), c.1546dupC, and c.1975G>C
(p.V659L) variants were each 4% (1/26)- revealed. Two male children, 11 years
old (SLC26A4: c.919-2A>G) and 7 years old (SLC26A4: c.919-2A>G:, SLC26A4:
c.2027T>A (p.L676Q))had history of born normal hearing and progressive hearing
loss.
Conclusions
1. 26 variants of bi-allelic SLC26A4 gene mutation were detected
in Mongolian people with EVA and Mondini malformation, and c.919-2A>G was
the most dominant allele variant, and rare variants such as c.1546dupC, c.716T>A
(p.V239D) were detected.
2. Our study shows that whole-exome sequencing (WES) can identify gene
mutations that are not detected by polymerase chain reaction (PCR) or NGS analysis.


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