Consanguinity profile in the Gaza Strip of Palestine: Large-scale community-based study

Distribution of pathogenic variants in the CFTR gene in a representative cohort of people with cystic fibrosis in the Kingdom of Bahrain

BACKGROUND

Cystic fibrosis (CF) is a rare multi-systemic recessive disorder. The spectrum and the frequencies of CFTR mutations causing CF vary amongst different populations in Europe and the Middle East. In this study, we characterised the distribution of CF-causing mutations (i.e. pathogenic variants in the  CFTR gene) in a representative CF cohort from the Kingdom of Bahrain based on a three-decade-long analysis at a single tertiary centre. We aim to improve CF genetic diagnostics, introduce of CF neonatal screening and provide CFTR modulator therapy (CFTRm).

METHODS

CFTR genotyping  and associated clinical information were drawn from a longitudinal cohort. We sequenced 56 people with CF (pwCF) that had one or both CFTR mutations unidentified and carried out comprehensive bioinformatic- and family-based segregation analyses of detected variants, including genotype-phenotype correlations and disease incidence estimates. The study methodology could serve as a basis for other non-European CF populations with a high degree of consanguinity.

RESULTS

Altogether 18 CF-causing mutations  were identified, 15 of which were not previously detected in Bahrain, accounting for close to 100% of all population-specific alleles. The most common alleles comprise c.1911delG [2043delG; 22.8%], c.2988+1G > A [3120+1G>A; 16.3%], c.2989-1G>A [3121-1G>A; 14.1%], c.3909C>G [N1303K; 13.0%], and c.1521_1523delCTT [p.PheF508del; 7.6%]. Although the proportion of 1st cousin marriages has decreased to 50%, the frequency of homozygosity in our pwCF is 67.4%, thereby indicating that CF still occurs in large, often related, families. pwCF in Bahrain present with faltering growth, pancreatic insufficiency and classical sino-pulmonary manifestations. Interestingly, two pwCF also suffer from sickle cell disease. The estimated incidence of CF in Bahrain based on data from the last three decades is 1 in 9,880 live births.

CONCLUSION

The most commonCF-causing  mutations in Bahraini pwCF were identified, enabling more precise diagnosis, introduction of two-tier neonatal screening and fostering administration of CFTRm.

Assessment of genetic familiarity and genetic knowledge among Palestinian university students

BACKGROUND AND AIMS

Genetic knowledge and familiarity among the population represent the lane toward effective participation in social decisions regarding genetic issues. This cross sectional research aimed to assess genetic knowledge and familiarity among university students in Palestine.

METHODS

The familiarity with genetics was evaluated using the Genetic Literacy and Comprehension instrument (GLAC), and genetic knowledge was measured using a 16-item scale of prevalent genetic concepts.

RESULTS

Among the 624 participants, 59.5% were females. 38.8% reported family history of genetic diseases. The genetic familiarity mean score was 4.83 and the genetic knowledge mean total score was 11.5. Students' genetic familiarity was high for the terms chromosome and genetic while it was low for the terms sporadic and vulnerability. Genetic knowledge was highest for gene definition while it was the lowest regarding the number of human genes. The age group, year of study, and learning genetic courses were the significant predictors of familiarity among medical students. The year of study, family history of genetic diseases, parental consanguinity, and learning genetic courses were the significant variables associated with genetic knowledge among medical students. Regarding the non-medical group of participants, all study variables were significant for both familiarity and knowledge scores except for age group with familiarity.

CONCLUSION

Genetic familiarity and knowledge among Palestinian university students are inadequate. Consanguinity and hereditary disorders are prevalent in Palestine. These findings encourage university stakeholders to take action to improve genetic knowledge and familiarity among students through both appropriate pedagogical and non-pedagogical interventions.

Assessment of Perceptions and Predictors Towards Consanguinity: A Cross-Sectional Study from Palestine

Background/Aim

Consanguinity represents a biological relationship between two individuals. In clinical genetics, it specifically refers to the marriage between individuals who are second cousins or closer. The aim of the study is to assess perceptions and their predictors among the Palestinian population towards consanguinity.

Methods

A survey-based cross-sectional study was conducted. The sample was collected using convenience and snowball sampling methods, yielding a sample of 1008 participants. The perceptions towards consanguinity and its predictors were assessed using Chi-square test.

Results

The prevalence of consanguinity among married participants was 18.7% (N = 81/432), while it was 28.8% among their parents. Consanguinity rate was significantly low among the young age group (ie, <47 years old) and among participants whose mothers have undergraduate educational levels (P < 0.05). Other factors like parental consanguinity, educational level of participants, their father's educational level, and residency place showed no significant associations (P > 0.05). Rejection of consanguinity was significantly noted among young age participants, absence of parental consanguinity, the presence of children or family members with genetic disorders and female gender (P < 0.001). Furthermore, participants who indicated that they are governmental employees, those with 2000-5000 ILS monthly income, those who are married (P < 0.01), and those who indicated that their mothers are holders of postgraduate degree were significantly more likely to reject the idea of consanguinity (P < 0.05). Also, medical and/or scientific reasons were significantly associated with rejecting the idea of consanguinity (P < 0.001).

Conclusion

Consanguinity prevalence has decreased among recent generations in Palestine, but it remains a significant challenge in Palestine. Therefore, educational and awareness programs about consanguinity and its health effects are effective strategies for reducing the consanguinity rate, especially for persons who are at the age of marriage.

The Palestinian primary ciliary dyskinesia population: first results of the diagnostic and genetic spectrum

Background

Diagnostic testing for primary ciliary dyskinesia (PCD) started in 2013 in Palestine. We aimed to describe the diagnostic, genetic and clinical spectrum of the Palestinian PCD population.

Methods

Individuals with symptoms suggestive of PCD were opportunistically considered for diagnostic testing: nasal nitric oxide (nNO) measurement, transmission electron microscopy (TEM) and/or PCD genetic panel or whole-exome testing. Clinical characteristics of those with a positive diagnosis were collected close to testing including forced expiratory volume in 1 s (FEV₁) Global Lung Index z-scores and body mass index z-scores.

Results

68 individuals had a definite positive PCD diagnosis, 31 confirmed by genetic and TEM results, 23 by TEM results alone, and 14 by genetic variants alone. 45 individuals from 40 families had 17 clinically actionable variants and four had variants of unknown significance in 14 PCD genes. CCDC39, DNAH11 and DNAAF11 were the most commonly mutated genes. 100% of variants were homozygous. Patients had a median age of 10.0 years at diagnosis, were highly consanguineous (93%) and 100% were of Arabic descent. Clinical features included persistent wet cough (99%), neonatal respiratory distress (84%) and situs inversus (43%). Lung function at diagnosis was already impaired (FEV₁ z-score median -1.90 (-5.0-1.32)) and growth was mostly within the normal range (z-score mean -0.36 (-3.03-2.57). 19% individuals had finger clubbing.

Conclusions

Despite limited local resources in Palestine, detailed geno- and phenotyping forms the basis of one of the largest national PCD populations globally. There was notable familial homozygosity within the context of significant population heterogeneity.

One person can make a difference: identification of people with a rare genetic lung disease

To improve access to care for rare conditions in resource-restricted regions, a concerted effort to establish centres of excellence and training of local physicians is needed https://bit.ly/3ZTBvaj.

Mapping the Diverse Genetic Disorders and Rare Diseases Among the Syrian Population: Implications on Refugee Health and Health Services in Host Countries

The aim of this systematic review is to provide physicians and researchers with a comprehensive list of reported genetic disorders in patients of Syrian origin-those who have become part of the largest displaced population globally-and to highlight the need to consider migrant population-based risk for the development of genetic disease control and prevention programs. This review was performed based on the 2015 PRISMA and the international prospective register of systematic reviews. The present review reports on a total of 166 genetic disorders (only 128 reported on OMIM) identified in the Syrian population. Of these disorders, 27% are endocrine-, nutritional- and metabolic-related diseases. Second to metabolic disorders are congenital malformations, deformations and chromosomal abnormalities. Diseases of the blood and the blood-forming organs accounted for 13% of the total genetic disorders. The majority of the genetic disorders reported in Syrian patients followed an autosomal recessive mode of inheritance. These findings are a reflection of the high rates of consanguineous marriages that favor the increase in incidence of these diseases. From the diseases that followed an autosomal recessive mode of inheritance, 22% are reported to be only present in Syria and other regional countries. Twelve of these genetic diseases were identified to be strictly diagnosed in individuals of Syrian origin. The present systematic review highlights the need to develop programs that target genetic disorders affecting Syrian migrants in host countries. These programs would have potential financial and economic benefits, as well as a positive impact on the physical and mental health of members of the Syrian refugee community and those of their host societies. In turn, this would decrease the burden on the health systems in host countries.

Molecular Understanding of Severe Cases of β-Thalassemia in the Nablus Region, West Bank, Palestine

Hemoglobinopathies are common inherited monogenic diseases that are likely to remain a serious regional health problem where thalassemias and sickle cell disease are prevalent. In regions where recessive alleles for hemoglobinopathy disorders are present with high consanguinity rates, such as in Palestine, coinheritance of two different genetic defects becomes anticipated and prevalent. In this report, we characterize the molecular variants of the HBB gene for 16 patients with transfusion-dependent anemia registered at the Thalassemia Patient Friends Society in Nablus governorate, West Bank, Palestine. Analysis revealed that 63.0% (10/16) of the patients were homozygous for β-thalassemia (β-thal), IVS-I-6 (T>C) (HBB: c.92+6T>C) or IVS-I-110 (G>A) (HBB: c.93-21G>A); 19.0% (3/16) homozygous for sickle cell disease or Hb S (HBB: c.20A>T, p.Glu6Val); 13.0% (2/16) were double heterozygotes for Hb S/β-thal, (HBB: c.20A>T/HBB: c.92G>C) and HBB: c.20A>T/HBB: c.321_322insG; and one case was a compound heterozygote for β-thal, codon 39 (C>T) (HBB: c.118C>T) and IVS-I-110. The most common mutation reported in the 16 patients was IVS-I-6 (0.38), followed by IVS-I-110 (0.28) Hb S (0.25) and 0.03 each for codon 39, codons 106/107 (HBB: c.321_322insG) and Hb Monroe (HBB: c.92G>C). In conclusion, in Palestine, a variety of intricate inheritance patterns are encountered in clinical practice.

Has the long-predicted decline in consanguineous marriage in India occurred?

To an extent the question posed in the title of this paper can simply be answered in the affirmative. Based on the extensive data available from the National Family Health Survey-1 (NFHS-1) conducted in 1992-93 and NFHS-4 in 2015-16 there has been a significant overall decline of some 19% in the prevalence of consanguineous marriage in India. However, when examined at state level the picture is more complex, with large reductions in consanguinity in southern states where intra-familial marriage previously has been strongly favoured, whereas in some northern states in which close kin unions traditionally have been proscribed small increases were recorded. In a country such as India, comprising an estimated 18% of the current world population and with multiple ethnic, religious, geographical and social sub-divisions, apparently contrary findings of this nature are not unexpected - especially given the major shifts that are underway in family sizes, in education and employment, and with rapid urbanization. The changing health profile of the population also is an important factor, with non-communicable diseases now responsible for a majority of morbidity and premature mortality in adulthood. The degree to which future alterations in the prevalence and profile of consanguineous marriage occur, and at what rate, is difficult to predict - the more so given the markedly diverse cultural identities that remain extant across the Sub-Continent, and ongoing intra-community endogamy.

Hemoglobinopathies in the North of Morocco: Consanguinity Pilot Study

Consanguinity is a social behavior characterized by the arrangement of marriages between relatives. It coincides generally with the geographic distribution of recessive genetic diseases as it increases the likelihood of homozygosis and, consequently, the incidence of their pathologies in the population. In this pilot study, we assess the effect of inbreeding on the burden of hemoglobinopathies in Northern Morocco. From January 2016 to December 2018, 197 children born in the studied region to three ancestral generations and diagnosed with hemoglobinopathies were subject to investigation. The rate of consanguinity in the parents' generation of children with hemoglobinopathies was 50.25%, with first cousin marriages accounting for 68.69% of consanguineous unions (FI = 0.02). The corresponding rates in the general population, based on a sample of N = 900, were 29.67% and 82.02%, respectively. The marriages between first cousins are the most common among the other types of consanguineous unions. Our study propounds that consanguinity substantially contributes to the hemoglobinopathy burden in the studied region and has changed little over time. Refraining from consanguineous marriages and detecting couples at risk could contribute to the reduction of the incidence of genetic diseases in our country.

The Influence of Consanguinity on Familial Clefting Among Palestinians

INTRODUCTION

Orofacial clefts (OFC) are the most common congenital craniofacial anomaly. The relationship between intermarriage (consanguinity) and positive family history for OFC is not well described. Consanguinity rates in developed countries are <1% but are considerably higher in the Middle East (45%). Familial clefting rates in developed countries are under 20% but in the Middle East are reported at 30% or higher.

OBJECTIVE

To determine OFC demographics and to clarify the relationship between consanguinity and familial clefting among Palestinians.

DESIGN

The Palestinian Congenial Anomalies Database is based on a 700-question survey administered to mothers of children with congenital anomalies. Orofacial clefts were diagnosed in 540 children. All demographic data were analyzed using χ² tests with a level of significance at α < .05.

RESULTS

Demographics for OFC among Palestinians were similar to other published reports. Overall consanguinity rate was 53% and familial clefting rate was 49%. Parental rates of consanguinity were significantly different for patients with cleft palate. Patients with consanguineous parents had a higher rate of positive family history of clefting (67%). Recurrence of clefts in siblings was significantly higher among those born to consanguineous parents (73%) when compared to nonconsanguineous parents.

CONCLUSION

Consanguinity rates for Palestinians with OFC were higher than those reported in the Middle East. Familial clefting and sibling recurrence rates were also higher than expected. The risk of OFC may be mitigated with improved education about anticipated genetic consequences of consanguinity in high-risk populations such as the southern West Bank.

Genetic analysis of osteogenesis imperfecta in the Palestinian population: molecular screening of 49 affected families

BACKGROUND

Osteogenesis imperfecta (OI) is a heterogeneous hereditary connective tissue disorder clinically hallmarked by increased susceptibility to bone fractures.

METHODS

We analyzed a cohort of 77 diagnosed OI patients from 49 unrelated Palestinian families. Next-generation sequencing technology was used to screen a panel of known OI genes.

RESULTS

In 41 probands, we identified 28 different disease-causing variants of 9 different known OI genes. Eleven of the variants are novel. Ten of the 28 variants are located in COL1A1, five in COL1A2, three in BMP1, three in FKBP10, two in TMEM38B, two in P3H1, and one each in CRTAP, SERPINF1, and SERPINH1. The absence of disease-causing variants in the remaining eight probands suggests further genetic heterogeneity in OI. In general, most OI patients (90%) harbor mainly variants in type I collagen resulting in an autosomal dominant inheritance pattern. However, in our cohort almost 61% (25/41) were affected with autosomal recessive OI. Moreover, we document a 21-kb genomic deletion in the TMEM38B gene identified in 29% (12/41) of the tested probands, making it the most frequent OI-causing variant in the Palestinian population.

CONCLUSION

This is the first genetic screening of an OI cohort from the Palestinian population. Our data are important for genetic counseling of OI patients and families in highly consanguineous populations.

Mutations in TRAPPC12 Manifest in Progressive Childhood Encephalopathy and Golgi Dysfunction

Progressive childhood encephalopathy is an etiologically heterogeneous condition characterized by progressive central nervous system dysfunction in association with a broad range of morbidity and mortality. The causes of encephalopathy can be either non-genetic or genetic. Identifying the genetic causes and dissecting the underlying mechanisms are critical to understanding brain development and improving treatments. Here, we report that variants in TRAPPC12 result in progressive childhood encephalopathy. Three individuals from two unrelated families have either a homozygous deleterious variant (c.145delG [p.Glu49Argfs^∗14]) or compound-heterozygous variants (c.360dupC [p.Glu121Argfs^∗7] and c.1880C>T [p. Ala627Val]). The clinical phenotypes of the three individuals are strikingly similar: severe disability, microcephaly, hearing loss, spasticity, and characteristic brain imaging findings. Fibroblasts derived from all three individuals showed a fragmented Golgi that could be rescued by expression of wild-type TRAPPC12. Protein transport from the endoplasmic reticulum to and through the Golgi was delayed. TRAPPC12 is a member of the TRAPP protein complex, which functions in membrane trafficking. Variants in several other genes encoding members of the TRAPP complex have been associated with overlapping clinical presentations, indicating shared and distinct functions for each complex member. Detailed understanding of the TRAPP-opathies will illuminate the role of membrane protein transport in human disease.

tRNA N6-adenosine threonylcarbamoyltransferase defect due to KAE1/TCS3 (OSGEP) mutation manifest by neurodegeneration and renal tubulopathy

Post-transcriptional tRNA modifications are numerous and require a large set of highly conserved enzymes in humans and other organisms. In yeast, the loss of many modifications is tolerated under unstressed conditions; one exception is the N⁶-threonyl-carbamoyl-adenosine (t⁶A) modification, loss of which causes a severe growth phenotype. Here we aimed at a molecular diagnosis in a brother and sister from a consanguineous family who presented with global developmental delay, failure to thrive and a renal defect manifesting in proteinuria and hypomagnesemia. Using exome sequencing, the patients were found to be homozygous for the c.974G>A (p.(Arg325Gln)) variant of the KAE1 gene. KAE1 is a constituent of the KEOPS complex, a five-subunit complex that catalyzes the second biosynthetic step of t⁶A in the cytosol. The yeast KAE1 allele carrying the equivalent mutation did not rescue the t⁶A deficiency of the kae1Δ yeast strain as efficiently as the WT allele; furthermore, t⁶A levels quantified by LC-MS/MS were lower in the kae1Δ strain which was complemented by the mutation than in the kae1Δ strain, which was complemented by the WT allele. We conclude that homozygosity for c.974G>A (p.(Arg325Gln)) in KAE1 likely exerts its pathogenic effect by perturbing t⁶A synthesis, thereby interfering with global protein production. This is the first report of t⁶A biosynthesis defect in human. KAE1 joins the growing list of cytoplasmic tRNA modification enzymes, all associated with severe neurological disorders.

National G6PD neonatal screening program in Gaza Strip of Palestine: rationale, challenges and recommendations

Congenital genetic disorders affecting neonates or young children can have serious clinical consequences if undiagnosed and left untreated. Early detection and an accurate diagnosis are, therefore, of major importance for preventing negative patient outcomes. Even though the occurrence of each specific metabolic disorder may be rare, their collective impact of preventable complications may be of considerable importance to the public health. Our previous studies showed that glucose-6-phosphate dehydrogenase (G6PD) deficiency is a problem of public health importance that has been shown to be a predominant cause of acute hemolytic anemia requiring hospitalization in Palestinian young children in Gaza Strip. Intriguingly, the majority of these children had one of the three variants, Mediterranean(c.) (563T) , African G6PD A-(c.) (202A) (/c.) (376G) and heretofore unrecognized as a common G6PD-deficient variant G6PD Cairo(c.) (404C) . The high prevalence of G6PD deficiency, as well as dietary factors in the region that precipitate anemia, argues for a need to protect the Palestinian children from a treatable and manageable genetic and metabolic disorder. This work reviews and discusses rationales and challenges of G6PD screening program in Gaza Strip. We advocate adopting a national neonatal G6PD screening program in Gaza Strip to identify children at risk and promote wellness and health for Palestine.