The association between consanguineous marriage and offspring with congenital hearing loss

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.

Hearing Screening in High-Risk Neonates Using Distortion Product Oto-Acoustic Emission

The prevalence of hearing loss is 0.09-2.3% in low risk neonates, and 0.3-14.1% in the high-risk population. The treatment requires early identification by neonatal hearing screening and early rehabilitation. OAE (oto-acoustic emission) and ABR (Auditory Brain Response) are the two objective tests used to evaluate hearing loss in neonates. OAE tests the biological response of the cochlea to auditory stimuli. ABR tests the auditory pathway. The aim is to estimate hearing loss in high-risk neonates using the Distortion Product Oto- acoustic emission (DP OAE) and to correlate the associated high-risk factors. This was a cross-sectional study conducted between March 2021 to September 2022. Newborns satisfying the inclusion criteria were included in the study. DP- OAE is performed to screen for hearing loss within 48 h of birth. Infants failing the first screening test are then examined for treatable causes and then repeated at 2 weeks. Newborns who fail the second DP-OAE are subjected to ABR for confirmation of hearing loss. A total of 100 high risk neonates underwent hearing screen using DP-OAE. Most common risk factors seen in our study are prematurity (22%), Low birth weight (< 2.5 kg) (20%), Neonatal Hyperbilirubinemia (17%), Maternal risk factors (GDM) (14%). Most neonates with prematurity failed the hearing test with significant p-value of 0.05. DP- OAE test can be successfully implemented as newborn hearing screening method, for early detection of hearing impairment to achieve the high quality standard of screening programs.

Hearing Loss Among Families with 2 and More Affected Members in Golestan Province, Iran: A Cross-Sectional Study of 320 Families

BACKGROUND

Our study centers on various aspects of families who have 2 or more members with hearing loss (HL) and are living in Golestan province in Iran. We aimed to identify those families with the highest probability of hereditary HL and also to examine the impact of consanguinity among them.

METHODS

The families included in the study underwent a comprehensive screening process that involved their prenatal and postnatal histories as well as family medical histories. Additionally, each patient received a thorough clinical ear examination. The evaluation also took into account factors such as patterns of inheritance, consanguinity, a 3-generation pedigree, and physical examination. Following this initial assessment, patients were referred for a complete hearing evaluation, which included pure-tone audiometry, speech recognition threshold, otoacoustic emission, and auditory brainstem response tests.

RESULTS

We identified a total of 8553 individuals living in Golestan province who are hearing impaired. Among those, our records indicate that 320 families had at least 2 affected members. The rate of consanguinity marriage in non-syndromic families was 64.43%. Also, a significant number (88.12%, or n=282) of the families exhibited hereditary HL, among which a substantial proportion (89.72%, or n=253) presented with nonsyndromic forms of HL. Furthermore, bilateral, stable, and prelingual HL were the most frequently observed types, and a majority of the patients were diagnosed with sensorineural and profound HL.

CONCLUSION

This study revealed a correlation between consanguinity and the incidence of familial HL, with more probability of bilateral, prelingual, sensorineural, and profound forms.

Autosomal Dominant Non-Syndromic Hearing Loss (DFNA): A Comprehensive Narrative Review

Autosomal dominant non-syndromic hearing loss (HL) typically occurs when only one dominant allele within the disease gene is sufficient to express the phenotype. Therefore, most patients diagnosed with autosomal dominant non-syndromic HL have a hearing-impaired parent, although de novo mutations should be considered in all cases of negative family history. To date, more than 50 genes and 80 loci have been identified for autosomal dominant non-syndromic HL. DFNA22 (MYO6 gene), DFNA8/12 (TECTA gene), DFNA20/26 (ACTG1 gene), DFNA6/14/38 (WFS1 gene), DFNA15 (POU4F3 gene), DFNA2A (KCNQ4 gene), and DFNA10 (EYA4 gene) are some of the most common forms of autosomal dominant non-syndromic HL. The characteristics of autosomal dominant non-syndromic HL are heterogenous. However, in most cases, HL tends to be bilateral, post-lingual in onset (childhood to early adulthood), high-frequency (sloping audiometric configuration), progressive, and variable in severity (mild to profound degree). DFNA1 (DIAPH1 gene) and DFNA6/14/38 (WFS1 gene) are the most common forms of autosomal dominant non-syndromic HL affecting low frequencies, while DFNA16 (unknown gene) is characterized by fluctuating HL. A long audiological follow-up is of paramount importance to identify hearing threshold deteriorations early and ensure prompt treatment with hearing aids or cochlear implants.

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.

Parental Consanguinity and Risk for Childhood Hearing Loss: A Retrospective Cohort Study

INTRODUCTION

Genetic causes are responsible for half of the cases of hearing loss, most of them being the result of non-syndromic genetic changes resulting from autosomal recessive inheritance. Parental consanguinity might be an indicator to consider in the diagnosis of these cases. The aim of this study was to assess its importance as a risk factor for childhood hearing loss.

MATERIAL AND METHODS

A retrospective cohort study conducted in a district hospital, between 2014 and 2018. We included all live births born during this period and excluded those with risk factors for childhood hearing loss other than parental consanguinity and those without hearing screening. We formed two study groups: newborns with parental consanguinity and newborns without risk factors. All the participants underwent hearing screening with the primary outcome of this study being the result of the screening. Those with a not normal result or with parental consanguinity also underwent diagnostic audiological evaluation.

RESULTS

Among 8513 live births, we studied 96 newborns with first-degree parental consanguinity and 96 newborns without risk factors. We found a statistically significant difference (p = 0.007) between the groups, with a 'refer' screening result rate of 24% in the group with parental consanguinity and 9.4% in the group without risk factors. We diagnosed one case of sensorineural hearing loss and another of mixed hearing loss in the first group and none of these cases in the second.

CONCLUSION

Parental consanguinity was associated with a higher risk of a refer screening result in newborns, which suggests the need to consider this as a risk factor for childhood hearing loss.

Prevalence, risk factors, and audiological characteristics of auditory neuropathy

OBJECTIVE

The objective of this study was to determine the prevalence, risk factors, and audiological characteristics of auditory neuropathy spectrum disorder (ANSD) in the pediatric population.

DESIGN

A retrospective review of medical charts was conducted for children visiting two hospitals in Saudi Arabia.

STUDY SAMPLE

Medical records of 1025 patients with sensorineural hearing loss (SNHL) were reviewed. We analyzed the databases for results of audiological examinations, risk factors, and outcomes of intervention including hearing aid (HA) and cochlear implantation (CI).

RESULTS

Out of 1025 children with SNHL, 101 patients (9.85%) were identified to have ANSD. Audiological characteristics of the ANSD group revealed a severe-to-profound degree of hearing loss, all showed type A tympanogram and absent reflexes, absent auditory brainstem response (ABR) findings with present cochlear microphonic while otoacoustic emissions were absent in 54.5% of patients. The most prevalent risk factors for ANSD in this group were family history of hearing loss, consanguinity, hyperbilirubinemia, and low birth weight. Pure tone and speech detection thresholds improved significantly with CI compared to HA use in this sample of patients with ANSD.

CONCLUSION

This study shows that ANSD is not extremely rare among Saudi children with severe to profound hearing loss, with a prevalence of 9.85%.