Inherited factors in pre-eclampsia: Molecular genetic and epidemiological studies in a Sri Lankan population

Pre-eclampsia is a disorder of unknown aetiology that affects about 5% of Sri Lankan women during their pregnancy. It is most likely a multifactorial disorder that is caused by the interaction of genetic and environmental factors. Recent advances in genetics have resulted in a surge of investigations into genetic factors underlying pre-eclampsia. These studies have been conducted mainly in the white Caucasians in the West and the Japanese in the East. The investigations described in this thesis therefore were undertaken in a genetically distinct South Asian Sinhalese population in Sri Lanka and replicated in a white Caucasian population in Nottingham, UK. Four candidate genes; Epidermal Growth Factor (EGF) and Transforming Growth Factor Alpha (TGFA), which may play a role in placentation; Angiotensinogen (ANG), which is involved in blood pressure regulation; and 5,10-Methylenetetrahydrofolate reductase (MTHFR), which is an enzyme involved in folate metabolism, were examined. These investigations consisted of the following: Recruitment of 80 population volunteers each from the Sinhala, Sri Lankan Tamil and Moor racial groups in Sri Lanka, establishing the allele/haplotype frequency for the candidate genes in those volunteers and in 80 white Caucasian population volunteers, and comparing their allele/haplotype frequencies; recruitment of 180 Sinhalese women with pre-eclampsia and 180 normotensive pregnant Sinhalese women, establishing the allele/haplotype frequencies of the candidate genes in these women and in 74 white Caucasian women with pre-eclampsia and 81 normotensive pregnant white Caucasian women, comparing the pre-eclampsia phenotype of the Sinhalese with that of the white Caucasians, examining the association of the candidate genes with pre-eclampsia, and examining the association of the candidate genes with quantitative traits such as birth weight and blood pressure in normotensive pregnant women; and examining the functional effects of polymorphisms in the angiotensinogen gene on gene expression. The phenotyping results of the Sinhalese women reflect the severe morbidity associated with pre-eclampsia elsewhere, and highlight the severe perinatal mortality associated with pre-eclampsia in the Sinhalese. The population genetic results show considerable similarity between allele/haplotype frequencies of the Sri Lankan racial groups and considerable variation between them and the white Caucasians. The EGF gene was associated with pre-eclampsia in the Sinhalese and with the weight of babies at birth in both the Sinhalese and the white Caucasians. The TGFA, ANG and MTHFR genes were not associated with either pre-eclampsia or any quantitative trait. The angiotensinogen reporter gene expression studies revealed the possible existence of a repressor element in the 3' untranslated region of the angiotensinogen gene, but this finding needs confirmation by further investigations

Inherited factors in pre-eclampsia : molecular genetic and epidemiological studies in a Sri Lankan population

Pre-eclampsia is a disorder of unknown aetiology that affects about 5% of Sri Lankan women during their pregnancy. It is most likely a multifactorial disorder that is caused by the interaction of genetic and environmental factors. Recent advances in genetics have resulted in a surge of investigations into genetic factors underlying pre-eclampsia. These studies have been conducted mainly in the white Caucasians in the West and the Japanese in the East. The investigations described in this thesis therefore were undertaken in a genetically distinct South Asian Sinhalese population in Sri Lanka and replicated in a white Caucasian population in Nottingham, UK. Four candidate genes; Epidermal Growth Factor (EGF) and Transforming Growth Factor Alpha (TGFA), which may play a role in placentation; Angiotensinogen (ANG), which is involved in blood pressure regulation; and 5,10-Methylenetetrahydrofolate reductase (MTHFR), which is an enzyme involved in folate metabolism, were examined. These investigations consisted of the following: Recruitment of 80 population volunteers each from the Sinhala, Sri Lankan Tamil and Moor racial groups in Sri Lanka, establishing the allele/haplotype frequency for the candidate genes in those volunteers and in 80 white Caucasian population volunteers, and comparing their allele/haplotype frequencies; recruitment of 180 Sinhalese women with pre-eclampsia and 180 normotensive pregnant Sinhalese women, establishing the allele/haplotype frequencies of the candidate genes in these women and in 74 white Caucasian women with pre-eclampsia and 81 normotensive pregnant white Caucasian women, comparing the pre-eclampsia phenotype of the Sinhalese with that of the white Caucasians, examining the association of the candidate genes with pre-eclampsia, and examining the association of the candidate genes with quantitative traits such as birth weight and blood pressure in normotensive pregnant women; and examining the functional effects of polymorphisms in the angiotensinogen gene on gene expression. The phenotyping results of the Sinhalese women reflect the severe morbidity associated with pre-eclampsia elsewhere, and highlight the severe perinatal mortality associated with pre-eclampsia in the Sinhalese. The population genetic results show considerable similarity between allele/haplotype frequencies of the Sri Lankan racial groups and considerable variation between them and the white Caucasians. The EGF gene was associated with pre-eclampsia in the Sinhalese and with the weight of babies at birth in both the Sinhalese and the white Caucasians. The TGFA, ANG and MTHFR genes were not associated with either pre-eclampsia or any quantitative trait. The angiotensinogen reporter gene expression studies revealed the possible existence of a repressor element in the 3' untranslated region of the angiotensinogen gene, but this finding needs confirmation by further investigations.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Undiagnosed diseases: Needs and opportunities in 20 countries participating in the Undiagnosed Diseases Network International

Introduction: Rare diseases (RD) are a health priority worldwide, overall affecting hundreds of millions of people globally. Early and accurate diagnosis is essential to support clinical care but remains challenging in many countries, especially the low- and medium-income ones. Hence, undiagnosed RD (URD) account for a significant portion of the overall RD burden. Methods: In October 2020, the Developing Nations Working Group of the Undiagnosed Diseases Network International (DNWG-UDNI) launched a survey among its members, belonging to 20 countries across all continents, to map unmet needs and opportunities for patients with URD. The survey was based on questions with open answers and included eight different domains. Conflicting interpretations were resolved in contact with the partners involved. Results: All members responded to the survey. The results indicated that the scientific and medical centers make substantial efforts to respond to the unmet needs of patients. In most countries, there is a high awareness of RD issues. Scarcity of resources was highlighted as a major problem, leading to reduced availability of diagnostic expertise and research. Serious equity in accessibility to services were highlighted both within and between participating countries. Regulatory problems, including securing informed consent, difficulties in sending DNA to foreign laboratories, protection of intellectual property, and conflicts of interest on the part of service providers, remain issues of concern. Finally, most respondents stressed the need to strengthen international cooperation in terms of data sharing, clinical research, and diagnostic expertise for URD patients in low and medium income countries. Discussion: The survey highlighted that many countries experienced a discrepancy between the growing expertise and scientific value, the level of awareness and commitment on the part of relevant parties, and funding bodies. Country-tailored public health actions, including general syllabus of medical schools and of the education of other health professionals, are needed to reduce such gaps.VSh is supported by Health Systems Research Institute of Thailand (65-040). SJ is supported by National Medical Research Council, Singapore (Grants ID CSAINV21jun-0003 and CIRG22jul-0003).S

Unmet needs in countries participating in the undiagnosed diseases network international: an international survey considering national health care and economic indicators

BackgroundPatients, families, the healthcare system, and society as a whole are all significantly impacted by rare diseases (RDs). According to various classifications, there are currently up to 9,000 different rare diseases that have been recognized, and new diseases are discovered every month. Although very few people are affected by each uncommon disease individually, millions of people are thought to be impacted globally when all these conditions are considered. Therefore, RDs represent an important public health concern. Although crucial for clinical care, early and correct diagnosis is still difficult to achieve in many nations, especially those with low and middle incomes. Consequently, a sizeable amount of the overall burden of RD is attributable to undiagnosed RD (URD). Existing barriers and policy aspects impacting the care of patients with RD and URD remain to be investigated.MethodsTo identify unmet needs and opportunities for patients with URD, the Developing Nations Working Group of the Undiagnosed Diseases Network International (DNWG-UDNI) conducted a survey among its members, who were from 20 different nations. The survey used a mix of multiple choice and dedicated open questions covering a variety of topics. To explore reported needs and analyze them in relation to national healthcare economical aspects, publicly available data on (a) World Bank ranking; (b) Current health expenditure per capita; (c) GDP per capita; (d) Domestic general government health expenditure (% of GDP); and (e) Life expectancy at birth, total (years) were incorporated in our study.ResultsThis study provides an in-depth evaluation of the unmet needs for 20 countries: low-income (3), middle-income (10), and high-income (7). When analyzing reported unmet needs, almost all countries (N = 19) indicated that major barriers still exist when attempting to improve the care of patients with UR and/or URD; most countries report unmet needs related to the availability of specialized care and dedicated facilities. However, while the countries ranked as low income by the World Bank showed the highest prevalence of referred unmet needs across the different domains, no specific trend appeared when comparing the high, upper, and low-middle income nations. No overt trend was observed when separating countries by current health expenditure per capita, GDP per capita, domestic general government health expenditure (% of GDP) and life expectancy at birth, total (years). Conversely, both the GDP and domestic general government health expenditure for each country impacted the presence of ongoing research.ConclusionWe found that policy characteristics varied greatly with the type of health system and country. No overall pattern in terms of referral for unmet needs when separating countries by main economic or health indicators were observed. Our findings highlight the importance of identifying actionable points (e.g., implemented orphan drug acts or registries where not available) in order to improve the care and diagnosis of RDs and URDs on a global scale

Breast cancer surveillance in BRCA positive Sri Lankan women: health equity for a high-risk group at a limited resource setting

Abstract Background BRCA1 and BRCA2 pathogenic variants account for 90% of hereditary breast malignancies, incurring a lifetime breast cancer risk of 85% and 40–45% respectively, in affected individuals. Well-resourced health care settings offer genetic counselling and genetic screening for susceptible individuals, followed by intense breast cancer surveillance programmes for those identified at high risk of breast cancer. Such high standards of care are not available in countries with limited resources. This study assessed breast cancer surveillance behaviors among a cohort of BRCA positive Sri Lankan women. Methods A retrospective case review of all patients diagnosed with pathogenic variants in BRCA1 and BRCA2 genes from 2015 to 2022 at the Human Genetics Unit, Faculty of Medicine, University of Colombo was carried out followed by telephone interviews of the respondents. Patients who were not contactable, deceased, undergone bilateral mastectomy and males were excluded from the interview component of the study. Standard descriptive statistics were used to analyze the data using SPSS statistics version 25. Results Only 25 patients were diagnosed during the study period:14/25 women responded (6/25 deceased, 3/25 non-contactable; 2/25 excluded). 71.4% (10/14) had performed breast self-examination during the preceding month; 35.7% (5/14) had a clinical breast examination (CBE), and 50% (7/14) had undergone a screening/diagnostic mammogram during the last one year. 28.5% (4/14) had undergone both mammography and CBE; 21.45% (3/14) mammogram only, 7.1% (1/14) had CBE only. 42.8%(6/14) had not undergone any surveillance(mammography, CBE or MRI). None had dual screening with mammogram and MRI. 85.71% (12/14) women expressed willingness to participate in a regular screening programme if made available. Conclusion Fifty percent of BRCA1/2 positive women in our study had not undergone annual imaging-based surveillance by mammography or MRI, and none had undergone annual dual screening with mammography and MRI, indicating inadequate breast cancer surveillance in this high-risk group

Associations between disc space narrowing, anterior osteophytes and disability in chronic mechanical low back pain: a cross sectional study

Abstract Background Radiographic features of lumbar disc degeneration (LDD) are common findings in patients with chronic mechanical low back pain; however, its role in disability and intensity of pain is debatable. This study aims to investigate the associations of the x-ray features of LDD and lumbar spondylolisthesis with severity of disability and intensity of pain. Methods A cross-sectional study was conducted on 439 patients with chronic mechanical low back pain who attended the rheumatology clinic, National Hospital of Sri Lanka, Colombo, from May 2012 to May 2014. Severity of disability was measured using Modified Oswestry Disability Index and intensity of pain was assessed using numeric rating scale (0–100). X-ray features of LDD (disc space narrowing, anterior osteophytes and overall LDD) and spondylolisthesis were assessed in lateral recumbent lumbar x-rays (L1/L2 to L5/S1) and graded by a consultant radiologist blinded to clinical data. Generalised linear model with linear response was used to assess the associations of x-ray features of LDD with severity of disability and intensity of pain adjusting for age, gender, body mass index and pain radiating into legs. Results Mean age was 48.99 ± 11.21 and 323 (73.58%) were females. 87 (19.82%) were obese. Mean severity of disability was 30.95 ± 13.67 and mean intensity of pain was 45.50 ± 20.37. 69 (15.72%), 26 (5.92%) and 85 (19.36%) patients had grade 2 disc space narrowing, anterior osteophytes and overall LDD, respectively. 51 (11.62%) patients had lumbar spondylolisthesis. Grade of disc space narrowing and overall LDD were not associated with severity of disability or intensity of pain. The presence of lumbar spondylolisthesis was associated with severity of disability. Female gender and pain radiating into legs were associated with severity of disability and intensity of pain. Advancing age was associated with x-ray features of LDD and lumbar spondylolisthesis. Conclusions Lumbar spondylolisthesis is associated with severity of disability in patients with chronic mechanical low back pain. Associations of x-ray features of LDD with severity of disability and intensity of pain are inconclusive. Female gender and pain radiating into legs are significant confounders

The pattern of KRAS mutations in metastatic colorectal cancer: a retrospective audit from Sri Lanka

Abstract Objective Activating mutations in the KRAS gene, found in approximately 53% of metastatic colorectal cancer (mCRC) cases, can render epidermal growth factor receptor (EGFR) inhibitors ineffective. Regional differences in these mutations have been reported. This is the first study which aims to describe the pattern of KRAS mutations in a Sri Lankan cohort of mCRC patients. Results The KRAS genotypes detected in mCRC patients which have been maintained in an anonymized database were retrospectively analyzed. Of the 108 colorectal tissue samples tested, 25 (23.0%) had KRAS mutations. Overall, there were 68 (63.0%) males and 40 (37.0%) females. Among the KRAS positive cases, there were 14 (56.0%) males and 11 (44.0%) females. Their age distribution ranged from 29 to 85 years with a median age of 61 years. There were 15 patients (60.0%) with point mutations in codon 12 while 10 (40.0%) had a single mutation in codon 13. The most common KRAS mutation identified was p.Gly13Asp (40.0%), followed by p.Gly12Val (24.0%). Other mutations included p.Gly12Cys (12.0%), p.Gly12Ser (12.0%), p.Gly12Asp (8.0%), and p.Gly12Arg (4.0%). The codon 13 mutation was a G>A transition (40.0%), while G>T transversions (32.0%), G>A transitions (24.0%), and G>C transversions (4.0%) were found in the codon 12 mutations. The frequency of KRAS mutations was similar to that reported for Asian patients. However, in contrast to several published studies, the G>A transition in codon 12 (c.35G>A; p.Gly12Asp), was not the most common mutation within codon 12 in our cohort. This may be a reflection of the genetic heterogeneity in the pattern of KRAS mutations in mCRC patients but valid conclusions cannot be drawn from these preliminary findings due to the small size of the study sample

Variants of ACAN are associated with severity of lumbar disc herniation in patients with chronic low back pain.

Disc herniation is a complex spinal disorder associated with disability and high healthcare cost. Lumbar disc herniation is strongly associated with disc degeneration. Candidate genes of the aggrecan metabolic pathway may associate with the severity of lumbar disc herniation.This study evaluated the association of single nucleotide variants (SNVs) of the candidate genes of the aggrecan metabolic pathway with the severity of lumbar disc herniation in patients with chronic mechanical low back pain. In addition, we assessed the in-silico functional analysis of the significant SNVs and association of their haplotypes with the severity of lumbar disc herniation.A descriptive cross sectional study was carried out on 106 patients. Severity of disc herniation and disc degeneration were assessed on T2-weighted mid sagittal lumbar MRI scan. Sixty two exonic SNVs of ten candidate genes of aggrecan metabolic pathway (ACAN, IL1A, IL1B, IL6, MMP3, ADAMTS4, ADAMTS5, TIMP1, TIMP2 and TIMP3) were genotyped on a Sequenom MassARRAY iPLEX platform. Multivariable linear regression analysis was carried out using PLINK 1.9 software adjusting for age, gender, body mass index and severity of disc degeneration. Four online bioinformatics tools (Provean, SIFT, PolyPhen and Mutation Taster) were used for in-silico functional analysis.Mean age was 52.42 ± 9.42 years and 69.8% were females. The mean severity of disc herniation was 2.81 ± 1.98. The rs2272023, rs35430524, rs2882676, rs2351491, rs938609, rs3825994, rs1042630, rs698621 and rs3817428 variants and their haplotypes of ACAN were associated with the severity of lumbar disc herniation. However, only the rs35430524, rs938609 and rs3817428 variants of ACAN were detected as pathogenic by in-silico functional analysis.SNVs of ACAN and their haplotypes are associated with the severity of lumbar disc herniation. Functional genetic studies are necessary to identify the role of these significant SNVs in the pathogenesis of disc herniation

Summary of the sample characteristics of 106 patients who underwent both MRI scan of lumbar spine and genetic association analysis.

<p>Summary of the sample characteristics of 106 patients who underwent both MRI scan of lumbar spine and genetic association analysis.</p

Novel mutation in the SLC12A3 gene in a Sri Lankan family with Gitelman syndrome & coexistent diabetes: a case report

Abstract Background Gitelman syndrome (GS) is a rare autosomal recessively inherited salt-wasting tubulopathy associated with mutations in the SLC12A3 gene, which encodes for NaCl cotransporter (NCC) in the kidney. Case presentation In this report, we describe two siblings from a Sri Lankan non-consanguineous family presenting with hypokalaemia associated with renal potassium wasting, hypomagnesemia, hypocalciuria and hypereninemic hyperaldosteronism with normal blood pressure. Genetic testing showed that both were homozygotes for a novel missense mutation in exon 10 of the SLC12A3 gene [NM_000339.2, c.1276A > T; p.N426Y], which has not previously been reported in the literature in association with GS. Their mother was a heterozygous carrier for the same mutation. The father was not alive at the time of testing. This novel mutation extends the spectrum of known SLC12A3 gene mutations and further supports the allelic heterogeneity of GS. Interestingly both siblings had young onset Diabetes with strong family history. Conclusion These findings have implications in providing appropriate genetic counseling to the family with regard to the risk associated with inbreeding, the detection of carrier/presymptomatic relatives. It further expands the known spectrum of genotypic and phenotypic characteristics of Gitelman syndrome