Consanguineous marriage and congenital heart defects: a case-control study in the neonatal period

Analysis of perinatal outcomes of pregnancies from consanguineous marriages in a tertiary hospital in Bursa, Turkey

Aim: In this article, we aimed to contribute to the outcomes of the consanguineous marriage literature by analyzing fetal results in this population. Material and Method: We included 185 patients in this retrospective research. Demographic, clinical, ultrasonographic and delivery data were received from electronic patient records. Also, we recorded the postnatal results, and findings of the infants. By combining all the data, we reported a descriptive analysis of the results of our consanguineous marriage cases with perinatology follow-up. Results: We had 231 pregnant women in the study, and their mean age was 28.9 years. 117 (50.6%) of the pregnant women had first-degree, and 114 (50.4%) had second-degree consanguineous marriages. Fetal findings were evaluated as usual in 157 (68%) of the pregnant in the ultrasonographic scans performed between prenatal 20-24 weeks of gestation. When we look at the first postnatal examinations of the babies, no abnormal findings were in 134 babies (58.8%). Twenty-two infants (9.6%) were followed up in the neonatal intensive care unit with the diagnosis of transient tachypnea of the newborn, and phototherapy was required in 14 infants (6.1%) due to hyperbilirubinemia. The number of cases requiring surgical intervention after delivery or with significant life-threatening anomalies included 56 findings in 32 infants. There were spina bifida cases in 8 infants and hydrocephalus in 9 infants. Conclusion: There was an increased level of congenital anomalies associated with consanguineous marriages. Health care centers should educate individuals regarding the negative role of cousin marriages leading to abnormalities in children.

Recurrence pattern of non-syndromic familial congenital heart diseases among a large cohort of families from Egypt

Background

Congenital heart diseases (CHD) are the commonest congenital anomalies with increased risk in children born from families with affected members. However, various recurrence patterns of CHDs have been reported in different populations. Therefore, this work aimed to assess the recurrence patterns of CHDs in a large sample of Egyptian families.

Methods

From January 2020 to October 2021, non-syndromic children with confirmed CHDs were recruited. Data were collected from guardians of the recruited children and hospital records, including the index case’s cardiac diagnosis and CHD diagnosis of other affected family members with to determine their recurrence pattern, consanguinity, and multi-gestation status.

Results

A total of 130 recurrent cases with CHD were documented in 1960 families of children with CHD, including 66,989 members. Most recurrences were detected among first-degree relatives 50/130 (38.46%), especially siblings. Discordant recurrence was the most detected pattern (45.38%), followed by concordant recurrence (42.31%), and the least was group concordance. Recurrence rate was the highest for septal defects with left ventricular outflow tract obstruction (LVOTO) (11.8%) and anomalous venous drainage (11.1%), followed by septal defect with right ventricular outflow tract obstruction (RVOTO) (9.4%), isolated ventricular septal defect (VSD) category (8.2%) and LVOTO (8%). Familial recurrence was significant in consanguineous marriages [p = 0.0001; OR (95%CI) = 4.5 (2.25–9.01)] and in multi-gestations siblings: [p = 0.036; OR (95%CI) = 12.5(1.03–6.04)].

Conclusion

The recurrence of non-syndromic CHD is evident among first-degree relatives in Egyptian families, with mostly a discordant recurrence pattern. Recurrence was more notable in septal defects with LVOTO, anomalous venous drainage, septal defect with RVOTO, isolated VSD, and isolated LVOTO diagnostic categories. This finding will significantly impact family counseling, emphasizing higher recurrence in consanguineous parents.

Supplementary information

The online version contains supplementary material available at 10.1186/s12887-022-03640-4.

Congenital heart diseases trends in São Paulo State, Brazil: a national live birth data bank analysis

BACKGROUND

Congenital heart diseases (CHD) are the most common type of birth defects, affecting millions of newborns every year; no prevalence data are available in São Paulo State, Brazil's most populous state. The objective is to identify trends in prevalence and risk factors for CHD in São Paulo State, Brazil.

METHODS

We developed a population-based study to estimate the CHD trend of prevalence in recent years, stratified by maternal age and geographical clusters, using all cases of CHD identified by the Live Births Information System (SINASC-Sistema de Informação Sobre Nascidos Vivos) from January 1, 2005, to December 31, 2018. We calculated the trends of prevalence, the regression coefficient (β), the annual percent change (APC), and 95% confidence interval using the Prais-Winsten regression model, with the Durbin-Watson test.

RESULTS

We found 10,594 cases of CHD among 8,536,101 live births (LB), a prevalence of 12.4/10,000 LB. There was no difference in the sex distribution; they are primarily Caucasian (60.2%), 75.2% born at term, and 74.4% weight > 2500 g, 66.9% of births were by cesarean section. São Paulo State presented an increasing CHD trend of prevalence (APC = 18.9%). The highest CHD prevalence rate was in mothers aged ≥ 35 years (22.2/10,000 LB). There were 12,271 specific congenital heart defects among 10,594 patients (1.16 CHD/patient). Atrial septal defect has the highest number of cases (3835), with a prevalence of 4.49/10,000 LB, corresponding to 31.3% of all CHD.

CONCLUSION

CHD had an increasing prevalence trend in recent years, being highest in São Paulo City and ≥ 35-year mothers.

Mutation spectrum of congenital heart disease in a consanguineous Turkish population

BACKGROUNDS

While many studies agree that consanguinity increases the rate of congenital heart disease (CHD), few genome analyses have been conducted with consanguineous CHD cohorts.

METHODS

We recruited 73 CHD probands from consanguineous families in Turkey and used whole-exome sequencing (WES) to identify genetic lesions in these patients.

RESULTS

On average, each patient had 6.95 rare damaging homozygous variants, 0.68 of which are loss-of-function (LoF) variants. Seven patients (9.6%) carried damaging homozygous variants in five causal CHD genes. Six of those patients exhibited laterality defects (six HTX and one D-TGA). Three additional patients (4.1%) harbored other types of CHD-associated genomic alterations, which overall explained 13.7% (10/73) of the cohort. The contribution from recessive variants in our cohort is higher than 1.8% reported from a cohort of 2871 CHD subjects where 5.6% of subjects met the criteria for consanguinity.

CONCLUSIONS

Our WES screen of a Turkish consanguineous population with structural CHD revealed its unique genetic architecture. Six of seven damaging homozygous variants in CHD causal genes occur in the setting of laterality defects implies a strong contribution from consanguinity to these defects specifically. Our study thus provided valuable information about the genetic landscape of CHD in consanguineous families in Turkey.

Risk factors for transposition of the great arteries in Saudi population

Objectives:

To assess potential risk factors and their effect on the development of transposition of the great arteries (TGA).

Methods:

A retrospective case-control study of all patients diagnosed with TGA between 1999 to 2016 at King Abdulaziz Medical City, Riyadh, Saudi Arabia. Age and gender-matched controls were selected. Risk factors, including consanguinity, gestational diabetes, family history of congenital heart disease, parental age, and maternal parity, were collected. Regression modeling was used to analyze the effects of risk factors on the development of TGA.

Results:

A total of 206 patients with transposition of the great arteries were enrolled in the study. Transposition of the great arteries cases were divided into simple and complex TGA. Selected healthy controls were 446. In the studied cases, consanguinity was found in 95 (46%) of cases, gestational diabetes was diagnosed in 36 (17.5%) mothers, and 35 (17%) had a confirmed family history of congenital heart disease. When risk factors of the cases were compared to the controls, consanguinity, gestational diabetes, maternal age, and parity were found to significantly increase the incidence of TGA.

Conclusion:

Our study revealed significant risk factors for the development of transposition of great arteries including first degree consanguineous marriages, gestational diabetes, family history of congenital cardiac anomalies, and increasing maternal age and parity. These factors increased the risk by at least 2 folds.

Genetic and reproductive consequences of consanguineous marriage in Bangladesh

Introduction

This study aimed to assess the prevalence, sociodemographic factors, reproductive consequences, and heritable disease burdens associated with consanguineous marriage (CM) in Bangladesh.

Methods

A total of 7,312 families, including 3,694 CM-families, were recruited from 102 locales of 58 districts of Bangladesh. Using a standard questionnaire, we collected medical history and background sociodemographic data of these families. Family history was assessed by pedigree analysis. Fertility, mortality, secondary sex ratio, selection intensity, lethal equivalents were measured using standard methods.

Results

The mean prevalence of CM in our studied population was 6.64%. Gross fertility was higher among CM families, as compared to the non-CM families (p < 0.05). The rate of under-5 child (U5) mortality was significantly higher among CM families (16.6%) in comparison with the non-CM families (5.8%) (p < 0.01). We observed a persuasive rise of abortion/miscarriage and U5 mortality rates with the increasing level of inbreeding. The value of lethal equivalents per gamete found elevated for autosomal inheritances as compared to sex-linked inheritance. CM was associated with the incidence of several single-gene and multifactorial diseases, and congenital malformations, including bronchial asthma, hearing defect, heart diseases, sickle cell anemia (p < 0.05). The general attitude and perception toward CM were rather indifferent, and very few people were concerned about its genetic burden.

Conclusion

This study highlights the harmful consequences of CM on reproductive behavior and the incidence of hereditary conditions. It essences the need for genetic counseling from premarital to postnatal levels in Bangladesh.

An interspecies heart-to-heart: Using Xenopus to uncover the genetic basis of congenital heart disease

PURPOSE OF REVIEW

Given the enormous impact congenital heart disease has on child health, it is imperative that we improve our understanding of the disease mechanisms that underlie patient phenotypes and clinical outcomes. This review will outline the merits of using the frog model, Xenopus, as a tool to study human cardiac development and left-right patterning mechanisms associated with congenital heart disease.

RECENT FINDINGS

Patient-driven gene discovery continues to provide new insight into the mechanisms of congenital heart disease, and by extension, patient phenotypes and outcomes. By identifying gene variants in CHD patients, studies in Xenopus have elucidated the molecular mechanisms of how these candidate genes affect cardiac development, both cardiogenesis as well as left-right patterning, which can have a major impact on cardiac morphogenesis. Xenopus has also proved to be a useful screening tool for the biological relevance of identified patient-mutations, and ongoing investigations continue to illuminate disease mechanisms.

SUMMARY

Analyses in model organisms can help to elucidate the disease mechanisms underlying CHD patient phenotypes. Using Xenopus to disentangle the genotype-phenotype relationships of well-known and novel disease genes could enhance the ability of physicians to efficaciously treat patients and predict clinical outcomes, ultimately improving quality of life and survival rates of patients born with congenital heart disease.

NKX2-5 molecular screening and assessment of variant rate and risk factors of secundum atrial septal defect in a Moroccan population

OBJECTIVE

Secundum atrial septal defect (ASDII) has multifactorial etiology that is combination of environmental (e.g., mother's exposure to toxicity, ethnicity) and genetic causes. Aim of the present study was to screen a Moroccan population with ASDII for NKX2-5 variants and to assess risk factors that may contribute to emergence of the disorder.

METHODS

Thirty-two non-syndromic ASDII patients were screened for NKX2-5 variants using direct sequencing of polymerase chain reactionamplified coding regions. Risk factor rates were compared to general population and assessed using Fisher's exact and chi-square tests. In this retrospective study, criteria of exclusion were suggestive or confirmed syndrome association.

RESULTS

Three heterozygous variants were detected in 4 patients. NKX2-5 variant rate in present cohort is estimated to be about 9.4%. Two prominent risk factors in the Moroccan population were highlighted: consanguinity, rate of which was significantly high at 30.8%, and previous maternal miscarriage or sibling sudden death, observed in 34.6% of cohort.

CONCLUSION

Impact of identified variants was discussed and possible disease-predisposing effect is suggested. Findings indicate that ASD may be favored by consanguineous marriage and that NKX2-5 variant rate in ASD patients may be affected by ethnicity. High level of maternal miscarriage and sibling sudden death suggests potential non-sporadic nature as result of putative genetic defect.

Genetic testing and genomic analysis: a debate on ethical, social and legal issues in the Arab world with a focus on Qatar

In 2013 both Saudi Arabia and Qatar launched genome projects with the aim of providing information for better diagnosis, treatment and prevention of diseases and, ultimately to realize personalized medicine by sequencing hundred thousands samples. These population based genome activities raise a series of relevant ethical, legal and social issues general, related to the specific population structure as well as to the Islamic perspective on genomic analysis and genetic testing. To contribute to the debate, the Authors after reviewing the existing literature and taking advantage of their professional experience in the field and in the geographic area, discuss and provide their opinions. In particular, the Authors focus on the impact of consanguinity on population structure and disease frequency in the Arab world, on genetic testing and genomic analysis (i.e. technical aspects, impact, etc.) and on their regulations. A comparison between the Islamic perspective and the ethical, social and legal issues raised in other population contexts is also carried. In conclusion, this opinion article with an up-to-date contribution to the discussion on the relevance and impact of genomic analysis and genetic testing in the Arab world, might help in producing specific national guidelines on genetic testing and genomic analysis and help accelerate the implementation and roll out of genome projects in Muslim countries and more specifically in Qatar, and other countries of the Gulf.

[The prevalence of symptomatic infantile heart disease at Louga Regional Hospital, Senegal]

La prise en charge des cardiopathies infantiles congénitales ou acquises dans les pays d’Afrique au sud du Sahara posent encore d’énormes difficultés de diagnostic et d’accès au traitement notamment chirurgical. Les objectifs de ce travail rétrospectif étaient de déterminer la prévalence des cardiopathies observées en milieu pédiatrique au Centre Hospitalier Régional (CHR) de Louga, de décrire les différents types observés et de rapporter leur évolution à court terme.

Durant la période d’étude, 1 Juillet 2009 au 31 Décembre 2012, 82 enfants sur 18 815 enfants présentaient une cardiopathie, soit une prévalence de 4.3/1 000. On note une prédominance du sexe féminin avec un sexe ratio de 1.2. Les circonstances de découverte les plus fréquentes sont représentées par la dyspnée 47.5% suivie du souffle cardiaque 35.3% et de l’insuffisance cardiaque congestive 13.4%. Les cardiopathies congénitales sont les plus fréquentes avec 69.5% des cas suivi des cardiopathies acquises avec 29.3% des cas et des formes mixtes avec 1.2%. Les principales cardiopathies congénitales retrouvées sont la communication inter ventriculaire (24.3%) suivie des canaux atrio-ventriculaires (12.1%), de la tétralogie de Fallot (9.7%) et de la persistance du canal artériel (7.3%). Les cardiopathies rhumatismales retrouvées dans 25.6% des cas et les péricardites tuberculeuses dans 3.7% des cas représentent les formes acquises. La mortalité est élevée avec 20 enfants décédés (24.4%) pendant la période d’étude. Seuls 13 patients sur 82 (15.9%) présentant une indication opératoire ont été opérés en France grâce à une prise en charge par l’association humanitaire Mécénat Chirurgie Cardiaque.

Ainsi donc les cardiopathies infantiles sont peu fréquentes dans le service de pédiatrie du CHR de Louga. Les formes congénitales sont plus fréquentes que les formes acquises. Leur mortalité est élevée et l’accès à la chirurgie reste faible.

Tetralogy of Fallot and Hypoplastic Left Heart Syndrome - Complex Clinical Phenotypes Meet Complex Genetic Networks

In many cases congenital heart disease (CHD) is represented by a complex phenotype and an array of several functional and morphological cardiac disorders. These malformations will be briefly summarized in the first part focusing on two severe CHD phenotypes, hypoplastic left heart syndrome (HLHS) and tetralogy of Fallot (TOF). In most cases of CHD the genetic origin remains largely unknown, though the complexity of the clinical picture strongly argues against a dysregulation which can be attributed to a single candidate gene but rather suggests a multifaceted polygenetic origin with elaborate interactions. Consistent with this idea, genome-wide approaches using whole exome sequencing, comparative sequence analysis of multiplex families to identify de novo mutations and global technologies to identify single nucleotide polymorphisms, copy number variants, dysregulation of the transcriptome and epigenetic variations have been conducted to obtain information about genetic alterations and potential predispositions possibly linked to the occurrence of a CHD phenotype. In the second part of this review we will summarize and discuss the available literature on identified genetic alterations linked to TOF and HLHS.

Complex genetics and the etiology of human congenital heart disease

Congenital heart disease (CHD) is the most common birth defect. Despite considerable advances in care, CHD remains a major contributor to newborn mortality and is associated with substantial morbidities and premature death. Genetic abnormalities appear to be the primary cause of CHD, but identifying precise defects has proven challenging, principally because CHD is a complex genetic trait. Mainly because of recent advances in genomic technology such as next-generation DNA sequencing, scientists have begun to identify the genetic variants underlying CHD. In this article, the roles of modifier genes, de novo mutations, copy number variants, common variants, and noncoding mutations in the pathogenesis of CHD are reviewed.

Consanguinity and isolated atrial septal defect in North East of Iran

BACKGROUND AND OBJECTIVES

The rate of consanguineous marriage is high in Middle Eastern countries such as Iran. The relationship between consanguineous marriage and congenital heart disease is discussed in some studies, but there is not much data for relationship between atrial septal defect (ASD) and consanguineous marriage. The aim of this study was to evaluate the relationship between consanguineous marriage and ASD echocardiographic characteristics.

DESIGN AND SETTINGS

This was a cross-sectional study approved by Mashhad University of Medical Sciences ethics committee and took place in Mashhad, Iran, for a period of 3 years from August 2008 till September 2011.

METHODS

In this cross-sectional study, 113 ASD patients participated and they were categorized into 3 groups on the basis of family relationship between their parents: first group-"no relationship," second group- "third degree relationship," and third group- "far relationship."

RESULTS

Among the 54 male and 59 female ASD patients, the most prevalent type of ASD was ASD secundum (85.0%) followed by sinus venosus (8.8%). A total of 56% patients were present in the first group and 15% and 29% in the second group and the third group, respectively." The relationship between consanguinity and type of ASD (P < .001) and gender (P < .001 each) was observed. The relationship between the age of onset of disease and consanguinity (P=.003) was also observed.

CONCLUSION

Considering the fact that there is a high prevalence of ASD and consanguineous marriage in Iran and bearing in mind the results of the present study, we recommend educating couples about the outcomes of consanguineous marriage in pre-marriage counseling.

The Congenital Heart Disease Genetic Network Study: rationale, design, and early results

Congenital heart defects (CHD) are the leading cause of infant mortality among birth defects, and later morbidities and premature mortality remain problematic. Although genetic factors contribute significantly to cause CHD, specific genetic lesions are unknown for most patients. The National Heart, Lung, and Blood Institute-funded Pediatric Cardiac Genomics Consortium established the Congenital Heart Disease Genetic Network Study to investigate relationships between genetic factors, clinical features, and outcomes in CHD. The Pediatric Cardiac Genomics Consortium comprises 6 main and 4 satellite sites at which subjects are recruited, and medical data and biospecimens (blood, saliva, cardiovascular tissue) are collected. Core infrastructure includes an administrative/data-coordinating center, biorepository, data hub, and core laboratories (genotyping, whole-exome sequencing, candidate gene evaluation, and variant confirmation). Eligibility includes all forms of CHD. Annual follow-up is obtained for probands <1-year-old. Parents are enrolled whenever available. Enrollment from December 2010 to June 2012 comprised 3772 probands. One or both parents were enrolled for 72% of probands. Proband median age is 5.5 years. The one third enrolled at age <1 year are contacted annually for follow-up information. The distribution of CHD favors more complex lesions. Approximately, 11% of probands have a genetic diagnosis. Adequate DNA is available from 97% and 91% of blood and saliva samples, respectively. Genomic analyses of probands with heterotaxy, atrial septal defects, conotruncal, and left ventricular outflow tract obstructive lesions are underway. The scientific community's use of Pediatric Cardiac Genomics Consortium resources is welcome.

Consanguinity and the risk of congenital heart disease

Consanguineous unions have been associated with an increased susceptibility to various forms of inherited disease. Although consanguinity is known to contribute to recessive diseases, the potential role of consanguinity in certain common birth defects is less clear, particularly since the disease pathophysiology may involve genetic and environmental/epigenetic factors. In this study, we ask whether consanguinity affects one of the most common birth defects, congenital heart disease, and identify areas for further research into these birth defects, since consanguinity may now impact health on a near-global basis. A systematic review of consanguinity in congenital heart disease was performed, focusing on non-syndromic disease, with the methodologies and results from studies of different ethnic populations compared. The risks for congenital heart disease have been assessed and summarized collectively and by individual lesion. The majority of studies support the view that consanguinity increases the prevalence of congenital heart disease, however, the study designs differed dramatically. Only a few (n = 3) population-based studies that controlled for potential sociodemographic confounding were identified, and data on individual cardiac lesions were limited by case numbers. Overall the results suggest that the risk for congenital heart disease is increased in consanguineous unions in the studied populations, principally at first-cousin level and closer, a factor that should be considered in empiric risk estimates in genetic counseling. However, for more precise risk estimates a better understanding of the underlying disease factors is needed.

Assessing the influence of consanguinity on congenital heart disease

Numerous articles have been published linking consanguineous marriage to an elevated prevalence of congenital heart disease, with ventricular septal defects and atrial septal defects the most commonly cited disorders. While initially persuasive, on closer examination many of these studies have fundamental shortcomings in their design and in the recruitment of study subjects and controls. Improved matching of cases and controls, to include recognition of the long-established community boundaries within which most marriages are contracted, and the assessment of consanguinity within specific levels and types of marital union would improve and help to focus the study outcomes. At the same time, major discrepancies between studies in their reported prevalence and types of congenital heart disease suggest an urgent need for greater standardization in the classification and reporting of these disorders.

Evolution in health and medicine Sackler colloquium: Consanguinity, human evolution, and complex diseases

There is little information on inbreeding during the critical early years of human existence. However, given the small founding group sizes and restricted mate choices it seems inevitable that intrafamilial reproduction occurred and the resultant levels of inbreeding would have been substantial. Currently, couples related as second cousins or closer (F >or= 0.0156) and their progeny account for an estimated 10.4% of the global population. The highest rates of consanguineous marriage occur in north and sub-Saharan Africa, the Middle East, and west, central, and south Asia. In these regions even couples who regard themselves as unrelated may exhibit high levels of homozygosity, because marriage within clan, tribe, caste, or biraderi boundaries has been a long-established tradition. Mortality in first-cousin progeny is approximately 3.5% higher than in nonconsanguineous offspring, although demographic, social, and economic factors can significantly influence the outcome. Improving socioeconomic conditions and better access to health care will impact the effects of consanguinity, with a shift from infant and childhood mortality to extended morbidity. At the same time, a range of primarily social factors, including urbanization, improved female education, and smaller family sizes indicate that the global prevalence of consanguineous unions will decline. This shift in marriage patterns will initially result in decreased homozygosity, accompanied by a reduction in the expression of recessive single-gene disorders. Although the roles of common and rare gene variants in the etiology of complex disease remain contentious, it would be expected that declining consanguinity would also be reflected in reduced prevalence of complex diseases, especially in population isolates.

Consanguinity and reproductive health among Arabs

Consanguineous marriages have been practiced since the early existence of modern humans. Until now consanguinity is widely practiced in several global communities with variable rates depending on religion, culture, and geography. Arab populations have a long tradition of consanguinity due to socio-cultural factors. Many Arab countries display some of the highest rates of consanguineous marriages in the world, and specifically first cousin marriages which may reach 25-30% of all marriages. In some countries like Qatar, Yemen, and UAE, consanguinity rates are increasing in the current generation. Research among Arabs and worldwide has indicated that consanguinity could have an effect on some reproductive health parameters such as postnatal mortality and rates of congenital malformations. The association of consanguinity with other reproductive health parameters, such as fertility and fetal wastage, is controversial. The main impact of consanguinity, however, is an increase in the rate of homozygotes for autosomal recessive genetic disorders. Worldwide, known dominant disorders are more numerous than known recessive disorders. However, data on genetic disorders in Arab populations as extracted from the Catalogue of Transmission Genetics in Arabs (CTGA) database indicate a relative abundance of recessive disorders in the region that is clearly associated with the practice of consanguinity.

Consanguinity and adverse pregnancy outcomes: the north of Jordan experience

This cross-sectional study was carried out to assess the association between consanguineous marriages and adverse pregnancy outcome in the north of Jordan. Women delivered in four major hospitals in the north of Jordan between April 2007 and May 2007 were included in the study. Non-Jordanian women and women with multiple pregnancies were excluded. Mothers answered a pilot-tested structured questionnaire administered by trained personnel in the maternity ward. Data regarding pregnancy outcomes were obtained from the patients' individual records. A total of 3,269 women with a mean age of 27.2 (SD 6.6) years were included. About 49% of women had consanguineous marriages. Consanguineous marriages were significantly associated with low birth weight delivery (13.9% vs. 10.1%), preterm delivery (19.9% vs. 12.3%), and births with congenital anomalies (4.1% vs. 0.8%) compared with non-consanguineous marriages. In the multivariate analysis, consanguinity was significantly associated with preterm delivery (OR = 1.5, 95% CI 1.2, 1.9), and congenital malformations (OR = 6.5, 95% CI 2.8, 15.3). In conclusions, this study supports the association between consanguinity and some adverse pregnancy outcomes.

Consanguinity and major genetic disorders in Saudi children: a community-based cross-sectional study

BACKGROUND AND OBJECTIVES

There is a high rate of consanguinity in Saudi Arabia; however, information on its relationship with genetic disorders is limited. The objective of this cross-sectional study was to explore the role of consanguinity in genetic disorders.

SUBJECTS AND METHODS

The study sample was determined by a multistage probability random sampling procedure. Consanguinity status was obtained during household visits. Primary care physicians performed a history and physical examination of all children and adolescents younger than 19 years, and all cases of genetic diseases were recorded. The chi-square test was used to compare proportions.

RESULTS

During the two-year study period (2004-2005), 11 554 of 11 874 (97%) mothers answered the question on consanguinity, and 6470 of 11 554 (56%) were consanguineous. There was no significant association between first-cousin consanguinity and Down syndrome (P=.55). Similarly, there was no significant association with either sickle cell disease (P=.97) or glucose-6-phosphate dehydrogenase deficiency (P=.67) for first-cousin consanguinity. A borderline statistical significance was found for major congenital malformations (P=.05). However, the most significant association with first-cousin consanguinity was congenital heart disease (CHD) (P=.01). Finally, no significant association was found for type 1 diabetes mellitus (P=.92). For all types of consanguinity, similar trends of association were found, with a definite statistically significant association only with CHD (P=.003).

CONCLUSION

The data suggest a significant role of parental consanguinity in CHD. However, a relationship between consanguinity and other genetic diseases could not be established. The effect of consanguinity on genetic diseases is not uniform and this should be taken into consideration in genetic counseling.

Familial muscular ventricular septal defects and aneurysms of the muscular interventricular septum

We describe 3 siblings with muscular ventricular septal defects, two requiring surgical closure. One of their offspring had a rare congenital aneurysm of the muscular ventricular septum, also requiring surgery. Another had a small muscular ventricular septal defect which closed spontaneously. Their father had echocardiographic evidence suggestive of a closed muscular defect. Paternal cousins have had ventricular septal defect, hypertrophic cardiomyopathy, and tetralogy of Fallot. There was no evidence of 22q11 deletion. Although ventricular septal defects are the most common congenital heart defect, such familial clustering is uncommon. The distribution of cases in this family suggests autosomal dominant inheritance. With echocardiography, and more precise diagnosis of defects which close, a larger genetic component may be revealed in other families.