Prevalence and determinants of consanguineous marriage and its types in India: evidence from the National Family Health Survey, 2015-2016

Exploring the clinical utility of exome sequencing/Mono, Duo, Trio in prenatal testing: a retrospective study in a tertiary care centre in South India

OBJECTIVES

With the availability of Next Generation Sequencing (NGS) diagnosis of genetic disorders has improved significantly. Its use is also applicable to ascertain diagnosis and management in a perinatal setting. The study aims to detect the genetic aetiology of various congenital structural and functional defects using NGS technology in the reproductive cohort at a tertiary centre. The secondary objective is to address challenges in the interpretation of variants.

METHODS

This was a retrospective study of couples who underwent exome sequencing (Mono-testing proband only or Duo-testing parents only or Trio-testing proband and parents) for suspected single gene disorders between years 2020-2022 at a tertiary care perinatal center in the South India. American College of Medical Genetics (ACMG) guidelines were followed to classify the pathogenicity of the variants identified by exome sequencing.

RESULTS

The overall diagnostic yield as defined by pathogenic/likely pathogenic variants obtained was (23/43) 53.4 %. The individual subsets have the following diagnostic yield viz., Mono 5/6 (83 %); Carrier 16/32 (50 %); Trio 2/5 (40 %). Diagnostic yield was significantly higher in consanguineous couples. However, miscarriage history, and organ system involvement did not have a significant effect on the diagnostic yield. Prenatal diagnosis was offered for seven patients based on the exome result. One fetus was confirmed with a compound heterozygous pathogenic variant.

CONCLUSIONS

Diagnostic yield of exome sequencing in our cohort was 53 %. The detection of pathogenic variants was maximum in those cases undergoing Mono exome sequencing. In places where there is a high prevalence of consanguinity and endogamy, NGS may be offered as first line test in the context of prenatal diagnosis.

Consanguineous marriage and associated diseases among their children and grandchildren in India: evidence from large-scale data

Worldwide, more than 130 million infants are born each year and a considerable number of 13.5 million of these children have inbred parents. The present study aimed to investigate the association between parents' consanguinity and chronic illness among their children and grandchildren in India. The nationally representative data, Longitudinal Aging Study in India, 2017-2018, Wave 1 was used for the present study. Bivariate analysis, a probit model, and propensity score estimation were employed to conduct the study. The study observed the highest prevalence of consanguinity marriage in the state of Andhra Pradesh (28%) and the lowest in Kerala (5%) among the south Indian States. People who lived in rural areas, belonged to the richer wealth quintile and Hindu religion were the significant predictors of consanguinity marriage in India. For individuals who were in consanguineous marriages, there was 0.85%, 0.84%, 1.57% 0.43%, 0.34%, and 0.14% chances of their children and grandchildren developing psychotic disorders, heart disease, hypertension stroke, cancer, and diabetes, respectively. Moreover, around 4.55% of the individuals have a history of birth defects or congenital disorders. To address the risk of complicated illnesses due to the consanguinity of marriage, medical, genetic, and social counselling services are required.

The association of hypertension among married Indian couples: a nationally representative cross-sectional study

Mounting evidence demonstrates that intimate partners sharing risk factors have similar propensities for chronic conditions such as hypertension. The objective was to study whether spousal hypertension was associated with one's own hypertension status independent of known risk factors, and stratified by socio-demographic subgroups (age, sex, wealth quintile, caste endogamy). Data were from heterosexual married couples (n = 50,023, women: 18-49 years, men: 21-54 years) who participated in the National Family Health Survey-V (2019-2021). Hypertension was defined as self-reported diagnosis of hypertension or average of three blood pressure measurements ≥ 140 systolic or 90 mmHg diastolic BP. Among married adults, the prevalence of hypertension among men (38.8 years [SD 8.3]) and women (33.9 years [SD 7.9]) were 29.1% [95% CI 28.5-29.8] and 20.6% [95% CI 20.0-21.1] respectively. The prevalence of hypertension among both partners was 8.4% [95% CI 8.0-8.8]. Women and men were more likely to have hypertension if their spouses had the condition (husband with hypertension: PR 1.37 [95% CI 1.30-1.44]; wife with hypertension: PR 1.32 [95% CI 1.26-1.38]), after adjusting for known risk factors. Spouse's hypertension status was consistently associated with own status across all socio-demographic subgroups examined. These findings present opportunities to consider married couples as a unit in efforts to diagnose and treat hypertension.

Consanguineous marriages, premarital screening, and genetic testing: a survey among Saudi university students

Background

Marriage among cousins or close relatives, i.e., consanguinity, is prevalent in many parts of the world, especially the Muslim world. Across civilizations, cultural norms, religious beliefs, and economic factors affect consanguineous marriages (CMs); however, such marriages have social, genetic, and health repercussions. The present study investigated the university students' attitudes regarding CMs and factors influencing their attitudes at King Abdulaziz University (KAU), Jeddah, Kingdom of Saudi Arabia (KSA).

Methods

This cross-sectional prospective study was conducted at KAU Jeddah in 2023. The questionnaire was distributed via electronic media (Emails, Facebook Messenger & WhatsApp). The convenience sampling technique was used to select participants, and descriptive and inferential statistics were used to analyze the data on SPSS-26.

Results

A total of 1707 university students were part of the study (females, 1,198, 70.2%; males, 509, 29.8%). Almost half of the participants, 819 (48.0%), had parents with CMs. Most of the participants, 1,391 (81.5%), had CMs in the family. Half of the participants disagreed that parents consider marriage stable due to high compatibility and the same social relationship before and after marriage. About one-third of respondents said parents believe family marriage transmits cultural values and continuity and keeps wealth in the family. More than three-fourths of the participants stated that if marriage is arranged with first cousins, they will opt for genetic analysis (82.5%) and premarital counseling (85.2%). The personal attitudes of females (p < 0.001), undergraduate (p = 0.02), and health sciences students (p = 0.02) were more positive than their counterparts. Males (OR = 0.41; p < 0.001) and non-health sciences students (OR = 0.68; p = 0.01) were less likely to have significant positive attitudes than their counterparts. Among participants who had CM parents, males (OR = 0.397; p < 0.001) and non-health sciences students (OR = 0.60; p = 0.01) and urban residents (OR = 0.59; p = 0.01) had significantly lower odds of having a positive attitude than their counterparts.

Conclusion

The practice of CMs is still prevalent in Saudi culture, with almost half of the participants having CM parents and the majority reporting these marriages in their families. Personal attitudes toward CMs were extremely positive. Most students prefer genetic testing and premarital counseling if marrying first cousins. Gender, faculty, parental income, and educational background influenced participants' attitudes.

The association of hypertension among married Indian couples: a nationally representative cross-sectional study

Mounting evidence demonstrates that intimate partners sharing risk factors have similar propensities for chronic conditions such as hypertension. The objective was to study whether spousal hypertension was associated with one's own hypertension status independent of known risk factors, and stratified by socio-demographic subgroups (age, sex, wealth quintile, caste endogamy). Data were from heterosexual married couples (n = 50,023, women: 18-49y, men: 21-54y) who participated in the National Family Health Survey-V (2019-21). Hypertension was defined as self-reported diagnosis of hypertension or average of three blood pressure measurements ≥ 140 systolic or 90 mmHg diastolic BP. Among married adults, the prevalence of hypertension among men (38.8 years [SD: 8.3]) and women (33.9 years [SD: 7.9]) were 29.1% [95%CI: 28.5-29.8] and 20.6% [95%CI: 20.0-21.1] respectively. The prevalence of hypertension among both partners was 8.4% [95%CI: 8.0-8.8]. Women and men were more likely to have hypertension if their spouses had the condition (husband with hypertension: PR = 1.37 [95%CI: 1.30-1.44]; wife with hypertension: PR = 1.32 [95%CI: 1.26-1.38]), after adjusting for known risk factors. Spouse's hypertension status was consistently associated with own status across all socio-demographic subgroups examined. These findings present opportunities to consider married couples as a unit in efforts to diagnose and treat hypertension.

Prevalence and socio-economic determinants of consanguineous marriages in Algeria according to Multiple Indicator Cluster Survey 2019 data (MICS6)

Consanguineous marriage is still a customary social phenomenon in Arab-Muslim communities. The aim of this study was to estimate the prevalence of consanguineous marriages in the Algerian population and to identify the socio-economic determinants associated with the practice of this form of union. This is a descriptive cross-sectional study included data for 21141 ever-married women aged 15-49 years, from the MICS6 Algeria (Multiple Indicator Cluster Survey database), conducted in 2019. Using a logistic regression model, we assessed the influence of socio-economic and geographical determinants on the practice of consanguineous marriages. The prevalence of consanguinity was 23.0% (95% CI: 22.4-23.6). According to multivariable binary logistic regression analysis, low level of education, early age at marriage (15-19; 20-30 years), rural area of residence, all geographical regions except the north-western territorial programming space, economic activity, and the lowest wealth index were the main determinants that assist in the prevalence of high rates of consanguineous marriages in Algeria. Considering these explanatory variables could help national health policy decision-makers to create and implement national preventive action plans that are intended alter behaviors attitudes toward preference of consanguineous marriages and, thus, reduce the burden of genetic disorders or congenital abnormalities associated with consanguinity.

The Impact of Increased Homozygosity on Human Fertility: A Comprehensive Review

This comprehensive review explores the multifaceted relationship between increased homozygosity and human fertility, delving into the genetic, ethical, cultural, and public health dimensions of this complex phenomenon. Homozygosity, characterized by identical alleles at specific gene loci, can result from consanguineous marriages, genetic drift, and population isolation. The review highlights key findings, including the heightened risk of recessive genetic disorders, the implications for immune system diversity, and the influence on complex traits and diseases. It underscores the critical role of genetic counseling in addressing these consequences, considering the ethical implications, and respecting cultural practices. The delicate balance between genetic diversity and cultural norms is emphasized, calling for increased awareness and community engagement. Looking ahead, the review suggests emerging technologies, longitudinal studies, and interdisciplinary research as crucial avenues for further exploration, with the ultimate goal of informing effective public health policies and interventions that safeguard genetic diversity and cultural traditions for future generations.

Whole-genome sequencing of 1029 Indian individuals reveals unique and rare structural variants

Structural variants contribute to genetic variability in human genomes and they can be presented in population-specific patterns. We aimed to understand the landscape of structural variants in the genomes of healthy Indian individuals and explore their potential implications in genetic disease conditions. For the identification of structural variants, a whole genome sequencing dataset of 1029 self-declared healthy Indian individuals from the IndiGen project was analysed. Further, these variants were evaluated for potential pathogenicity and their associations with genetic diseases. We also compared our identified variations with the existing global datasets. We generated a compendium of total 38,560 high-confident structural variants, comprising 28,393 deletions, 5030 duplications, 5038 insertions, and 99 inversions. Particularly, we identified around 55% of all these variants were found to be unique to the studied population. Further analysis revealed 134 deletions with predicted pathogenic/likely pathogenic effects and their affected genes were majorly enriched for neurological disease conditions, such as intellectual disability and neurodegenerative diseases. The IndiGenomes dataset helped us to understand the unique spectrum of structural variants in the Indian population. More than half of identified variants were not present in the publicly available global dataset on structural variants. Clinically important deletions identified in IndiGenomes might aid in improving the diagnosis of unsolved genetic diseases, particularly in neurological conditions. Along with basal allele frequency data and clinically important deletions, IndiGenomes data might serve as a baseline resource for future studies on genomic structural variant analysis in the Indian population.

Prevalence of Consanguineous Marriage among Saudi Citizens of Albaha, a Cross-Sectional Study

Consanguineous marriage (CM) is a prevalent kind of relationship in Muslim and Arab countries, and this type of relationship is linked to several health risks. This study was conducted to determine the prevalence of (CM), its associated hereditary diseases, and health-related issues among Saudi citizens in Albaha. This cross-sectional study was conducted between March 2021 to April 2021. Saudi citizens in Albaha who were aged ≥ 18 years and willing to participate were eligible for the study. A total of 1010 participants were included in this study. In total, 757 participants were married, widowed, or divorced. CM partnerships comprised 40% (N = 302) of the marriages among participants, of which first- and second-cousin marriages comprised 72% and 28%, respectively. The prevalence of CM among the participants' parents was lower than that among the participants (31% versus 40%, respectively). Children of participants in a CM were more likely to have cardiovascular diseases (p < 0.001), blood diseases (anaemia, thalassemia) (p < 0.001), cancer (p = 0.046), hearing loss and speech disorder (p = 0.003), and ophthalmic diseases (p = 0.037). Albaha showed a high percentage of consanguinity. An educational program must be established to enhance the population's knowledge of the consequences of CM. The current national premarital screening program should be extended to involve more screening tests for common hereditary diseases that result from CM.

The prevailing trend of consanguinity in the Arab society of Israel: is it still a challenge?

The aim of this study was to determine the trend of consanguineous marriage among the Arab population in Israel. Socio-demographic data for the Arab population were extracted from national health surveys conducted in Israel in 2007 and 2017. The prevalence of consanguineous marriage among the Arab population in Israel increased significantly from 36.3% to 41.6% in the decade from 2007 to 2017. First-cousin and closer marriages constituted about 50% of total consanguineous marriages in the two periods surveyed. Consanguinity was found to be significantly related to religion and place of residence. Thus, the prevalence of consanguineous marriage remains high among the Arab population in Israel, similar to other Arab societies. These findings affect the health of future generations and impose a challenge for health care professionals.

Congenital hypothyroidism in India: A systematic review and meta-analysis of prevalence, screen positivity rates, and etiology

Background

Congenital hypothyroidism (CH) is the leading cause of preventable mental retardation, which is currently not universally screened in India. Knowledge of the country-specific prevalence of the disease can guide in establishing a universal screening program.

Methods

We performed a systematic review and meta-analysis to assess the prevalence, screen positivity rates, compliance to recall and etiology of CH in India. The databases of PubMed, Embase, Google scholar and IMSEAR were searched on 1^st October 2021. All observational studies reporting at least one of the outcomes of interest were included. Two reviewers independently extracted the data and appraised the quality of studies using the Joanna Briggs tool for prevalence studies. Estimates were pooled using a random-effects model with double arcsine transformation (MetaXL software). PROSPERO database registration number was CRD42021277523.

Findings

Of the 2 073 unique articles retrieved, 70 studies were eligible for inclusion. The prevalence of CH (per 1 000 neonates screened) was 0·97 (95% confidence intervals/CI: 0·9, 1·04) in non-endemic areas (54 studies and 819 559 neonates), 79 (95% CI: 72, 86) in endemic areas (3 studies, 5 060 neonates), 50 (95% CI: 31, 72) in neonates born to mothers with thyroid disorders, and 14 (95% CI: 8, 22) in preterm neonates. At thyroid stimulation hormone cut-off of 20 mIU/L, the screen positivity rates were 5·6% (95% CI: 5·4%, 5·9%) for cord blood samples and 0·19% (95% CI: 0·18%, 0·2%) for postnatal sample. About 70% (95% CI: 70, 71) of screen positive neonates were retested with diagnostic tests. Among neonates with permanent hypothyroidism, thyroid dysgenesis 56·6% (95% CI: 50·9%, 62·2%) was more common than dyshormonogenesis 38·7% (95% CI: 33·2%, 44·3%).

Interpretation

The prevalence of congenital hypothyroidism in India is higher than global estimates. Screen positivity rate was higher for cord blood screening when compared to postnatal screening. Compliance with confirmatory testing was higher for cord blood screening.

Funding

The study was not funded by any source.

Consanguinity and ocular disorders in India: Electronic medical records driven big data analytics

Purpose:

To describe the distribution of ocular disorders in patients with a family history of consanguinity presenting to a multi-tier ophthalmology hospital network in India.

Methods:

This cross-sectional hospital-based study included 2,805,267 new patients presenting between August 2010 and April 2021. Patients with a family history of consanguinity were included as cases. The sociodemographic and clinical data were collected using an electronic medical record system.

Results:

Overall, 20,445 (0.73%) new patients were documented to have a family history of consanguinity. The prevalence rates were 4.04% in children (age: <16 years) and 0.21% in adults. The mean age of the patients was 11.87 ± 11.06 years. The majority of the patients were males (56.48%) and students (54.43%) by profession. The majority (93.05%) of the patients were in the 0–30-years age bracket, with over half of them (53.71%) presenting in the first decade of life. A significant number of patients were from higher socioeconomic status (73.48%) and the rural region (47.62%). The most common degree of consanguinity documented was second degree (3.95%). The most common ocular disorders associated with a high proportion of consanguinity were congenital hereditary endothelial dystrophy (CHED) (100%), corneal macular dystrophy (83.78%), xeroderma pigmentosum (80.95%), and ocular albinism (73.59%). A tenth of the patients (9.8%) reported a similar history of ocular disorders among the family members and more commonly among the siblings (70.4%).

Conclusion:

Consanguineous marriages are not uncommon in India. They cause ocular disorders that cause visual impairment in a significant majority of those affected in their early decades of life. Genetic counseling plays a role in prevention.

Inborn error of metabolism precipitated by COVID-19: challenges in the absence of an expanded newborn screening as state health programmes

Inborn errors of metabolism constitute a differential diagnosis in infants presenting with encephalopathy in developing countries where expanded newborn screening is not a state health programme. Acute neurological presentation with encephalopathy is documented in paediatric COVID-19. The pandemic has also altered parents' healthcare-seeking behaviour, leading to delays in emergency care. We illustrate the challenges faced in diagnosing and managing an 18-month-old child who presented with acute metabolic crisis due to methylmalonic acidaemia on the background of the COVID-19 pandemic. We discuss the current global status of expanded newborn screening services for inborn error of metabolism and the impact of the pandemic on the healthcare of children.

Is consanguineous marriage related to spousal violence in India? Evidence from the National Family Health Survey, 2015-16

Violence against women is a global phenomenon, and intimate partner violence is the most common form of violence faced by women in the world. Around 30% of women in the world, on average, and 33% in India experience intimate partner violence during their lifetime. The main aim of this study was to investigate whether consanguinity protects women from spousal violence. National Family Health Survey 2015-16 (NFHS-4) data were used. The study sample comprised 60,824 currently married women aged 15-49 years. The results of the logistic regression model showed that the likelihood of all types of spousal violence against women was higher among consanguineous unions compared with non-consanguineous unions in India. The association between consanguineous marriage and spousal violence was found to be positive and significant in the southern and eastern regions of India and among Scheduled Castes and Scheduled Tribes. The association was not significant among Muslims. Differences in socio-cultural norms and practices across the regions of India, and among different socio-cultural groups, can perhaps explain these variations. Women belonging in higher age groups, from Other Backward Castes, those who were working and those with a low level of educational attainment and socioeconomic standing had a higher risk of experiencing intimate partner violence. Couples in a consanguineous marriage should be given adequate counselling to reduce intimate partner violence in India, and similarly culturally diverse countries. This would also help reach Target 5.2 of the Sustainable Development Goals by 2030.