Cystic fibrosis in Arabs: a prototype from Jordan

Clinical and genetic risk factors for cystic fibrosis-related liver disease in Egyptian CF children: A single-center experience

BACKGROUND

Cystic fibrosis (CF) is an autosomal recessive disease. It affects multiple organ systems, including the liver, leading to CF-related liver disease (CFLD). It was noted that CFLD in Egyptian children with CF is more common than in non-Egyptian people with CF (pwCF). This study aimed to determine the incidence of CFLD and the potential risk factors for developing CFLD in Egyptian children. The correlation between CFLD and the various genotypes prevalent in Egyptian CF children will be discussed. In addition, comparison of CFLD in Egyptian and non-Egyptian CF patients will be presented.

METHODS

This cross-sectional study included 50 pwCF from Ain Sham University's Pediatric Pulmonology Clinic in Children's Hospital, Cairo, Egypt. The sweat chloride test and genetic studies were done at the time of diagnosis. Additionally, all subjects underwent detailed history taking, laboratory investigations, clinical assessment, and pelvic abdominal ultrasound for evaluation of hepatic involvement.

RESULTS

One-third of the Egyptian children with CF were found to have liver disease. The following independent risk factors for developing CFLD were identified as: male sex, severe genetic mutation (class I and II), long duration of CF disease, early onset of the CF, pancreatic insufficiency, as well as history of meconium ileus. In addition, diabetes mellitus and severe lung disease were proven to significantly increase the risk of developing CFLD.

CONCLUSION

CFLD is common in Egyptian pwCF. CFLD's risk factors are similar to other reported research from other countries in the region.

A comprehensive review of cystic fibrosis in Africa and Asia

Cystic fibrosis (CF) was earlier thought to be a disease prevalent in the West among Caucasians. However, quite a number of recent studies have uncovered CF cases outside of this region, and reported hundreds of unique and novel variant forms of CFTR. Here, we discuss the evidence of CF in parts of the world earlier considered to be rare; Africa, and Asia. This review also highlighted the CFTR mutation variations and new mutations discovered in these regions. This discovery implies that the CF data from these regions were earlier underestimated. The inadequate awareness of the disease in these regions might have contributed towards the poor diagnostic facilities, under-diagnosis or/and under-reporting, and the lack of CF associated health policies. Overall, these regions have a high rate of infant, childhood and early adulthood mortality due to CF. Therefore, there is a need for a thorough investigation of CF prevalence and to identify unique and novel variant mutations within these regions in order to formulate intervention plans, create awareness, develop mutation specific screening kits and therapies to keep CF mortality at bay.

A retrospective study of cases diagnosed with cystic fibrosis at a single care center in Syria

Background

Although there is relatively much information about the status of cystic fibrosis disease in different countries of the world, limited data are available on this disease among Syrian children. Therefore, we did a retrospective study that included 173 children diagnosed with cystic fibrosis according to the diagnostic criteria. This study was conducted to determine the diagnostic, clinical, and genetic characteristics of patients with cystic fibrosis in Syria and to assess the relationship between the genotype and the phenotype of disease in these patients.

Results

As a result of the early classical manifestations, CF diagnosis was established in the present study by the age of 1 year in 78.6%; the mortality rate was 23.1% (82.5% of them were in the first year of life). The prevalence of respiratory and gastrointestinal symptoms was 81.5% and 78.6%, respectively with an average age of 7.8 and 3.4 months. Consanguinity was reported in 75.7% of the families. The most common pathogenic variant in the sample was F508del (36%) followed by W1282X (17%). There was a statistical correlation between incidence of steatorrhea and the presence of class I pathogenic variants. A relationship between the mortality rate and the presence of class II pathogenic variants (pathogenic deletion variants) was also observed. There was no statistical relationship between other clinical manifestation and pathogenic variant classes. However, the incidence of most CF-related conditions was a little higher in the presence of classes I, II, and III pathogenic variants compared to their incidence in the presence of classes IV and V pathogenic variants.

Conclusions

The number of cases diagnosed with cystic fibrosis in Syria is less than the number of real cases, and there is a need to perform CFTR gene sequencing on large sample sizes, to determine all CFTR pathogenic variants that could exist in Syrian patients and to make a better evaluation of the relationship between genotype and phenotype of the disease.

Preliminary national report on cystic fibrosis epidemiology in Tunisia: the actual state of affairs

AIM

To establish a preliminary national report on clinical and genetic features of cystic fibrosis (CF) in Tunisian children as a first measure for a better health care organization.

METHODS

All children with CF diagnosed by positive sweat tests between 1996 and 2015 in children's departments of Tunisian university hospitals were included. Data was recorded at diagnosis and during the follow-up from patients' medical records.

RESULTS

In 12 departments, 123 CF children were collected. The median age at diagnosis was 5 months with a median diagnosis delay of 3 months. CF was revealed mostly by recurrent respiratory tract infections (69.9%), denutrition (55.2%), and/or chronic diarrhea (41.4%). The mean sweat chloride concentration was 110.9mmol/L. At least one mutation was found in 95 cases (77.2%). The most frequent mutations were Phe508del (n=58) and E1104X (n=15). Fifty-five patients had a Pseudomonas Aeruginosa chronic colonization at a median age of 30 months. Cirrhosis and diabetes appeared at a mean age of 5.5 and 12.5 years respectively in 4 patients each. Sixty-two patients died at a median age of 8 months. Phe508del mutation and hypotrophy were associated with death (p=0.002 and p<0.001, respectively).

CONCLUSION

CF is life-shortening in Tunisia. Setting-up appropriate management is urgent.

Spectrum of mutations of cystic fibrosis in the 22 Arab countries: A systematic review

Cystic fibrosis (CF) is an autosomal recessive genetic disease caused by mutations in the CFTR gene, with various clinical manifestations that affect pulmonary, digestive, exocrine and male reproductive functions as well as the bones and kidneys. This study aimed to reveal the spectrum of CFTR gene mutations in Arab CF patients and their corresponding clinical phenotypes among the 22 Arab countries. We searched four literature databases (PubMed, Science Direct, Web of Science and Scopus) from their times of inception to January 2018. All possible search terms were used to encompass the different clinical phenotypes, disease incidences, CFTR mutations, ages and consanguinity rates of CF patients in the 22 Arab countries. Our search strategy identified 678 articles; of these, 72 were eligible for this systematic review. We retrieved data from 18 Arab countries; only 1766 Arab patients with CF were identified, even after additional searches using Google and Google Scholar. The search uncovered a wide spectrum of mutations, some of which are shared with other ethnic groups and some unique to Arab patients. Although the clinical phenotypes of Arab patients were typical of CF, several distinct phenotypes were reported. Despite the rarity of genetic epidemiological studies of CF patients among the 22 Arab nations, the disease is frequently reported in Arab countries where consanguineous marriage is common. Therefore, significant attention should be paid to this problem by implementing carrier and premarital screening, newborn screening and genetic counselling.

Cystic fibrosis in Tunisian children: a review of 32 children

Background

Cystic fibrosis is rare in Tunisia. Its diagnosis requires experienced specialists. Its prognosis is poor in developing countries.

Objectives

To study the epidemiologic, clinical, genetic features and the therapeutic challenges of cystic fibrosis in Tunisian children.

Methods

Covering a period of 21 years, this retrospective study included all patients with a definite diagnosis of cystic fibrosis from the Pediatrics Department B of The Children's Hospital of Tunis.

Results

Data from 32 children (14 boys and 18 girls) were collected. The diagnosis was made during the first year of life in 28 cases. Meconium ileus was found in 5 cases, respiratory manifestations in 22 cases, chronic diarrhea in 19 cases, faltering growth in 17 cases and a pseudo Barter syndrome in 2 cases. The sweat chloride test was positive in all cases. The most frequent mutation was F508del (56% of cases). Respiratory complications marked the outcome. Among our 32 patients, 15 patients (50%) died at an average age of 5 years and 3 months, mainly due to respiratory failure. The mean age of the surviving patients was 5 years.

Conclusion

Cystic fibrosis prognosis is poor in our series compared to developed countries due to the longer diagnostic delay and the limited therapeutic options.

Epidemiology and genetics of cystic fibrosis in Asia: In preparation for the next-generation treatments

Cystic fibrosis (CF) in the Asian population is less frequently reported due to under-diagnosis and lack of centralized CF patient registries. Clinical studies on CF cases from Asia have documented a severe course of the disease. The spectrum of the cystic fibrosis transmembrane conductance regulator (CFTR) variants in this population is quite heterogeneous. In total, 166 variants have been reported on approximately 3700 Asian CF chromosomes. The frequency of F508del among Asians is low compared with Caucasians. Recent in vitro studies have shown promise of small molecule correction and potentiation of 45 different CFTR variants. Of these variants, 16 (including G551D and F508del) have also been observed among Asian CF individuals. We suggest undertaking molecular studies extensively to annotate CFTR variants that will help Asian CF individuals to benefit from the precision medicine gaining momentum in the Western countries.

The road for survival improvement of cystic fibrosis patients in Arab countries

Cystic fibrosis (CF) is a lethal, monogenic disorder that affects multiple organ systems of the body. The incidence has been described before in the Middle East to be 1 in 2000 to 1 in 5800 live births, and the median survival was estimated to be from 10 to 20 years of age. The present article attempts to revisit various facets of this disease and specifically highlights the most important lacunae that exist in treating CF. In addition, it also tries to emphasize the steps in improving the median survival of patients with CF, in these countries.

Next generation sequencing to determine the cystic fibrosis mutation spectrum in Palestinian population

An extensive molecular analysis of the CF transmembrane regulator (CFTR) gene was performed to establish the CFTR mutation spectrum and frequencies in the Palestinian population, which can be considered as an understudied population. We used a targeted Next Generation Sequencing approach to sequence the entire coding region and the adjacent sequences of the CFTR gene combined with MLPA analysis of 60 unrelated CF patients. Eighteen different CF-causing mutations, including one previously undescribed mutation p.(Gly1265Arg), were identified. The overall detection rate is up to 67%, and when we consider only CF patients with sweat chloride concentrations >70 mEq/L, we even have a pickup rate of 92%. Whereas p.(Phe508del) is the most frequent allele (35% of the positive cases), 3 other mutations c.2988+1Kbdel8.6Kb, c.1393-1G>A, and p.(Gly85Glu) showed frequencies higher than 5% and a total of 9 mutations account for 84% of the mutations. This limited spectrum of CF mutations is in agreement with the homozygous ethnic origin of the Palestinian population. The relative large portion of patients without a mutation is most likely due to clinical misdiagnosis. Our results will be important in the development of an adequate molecular diagnostic test for CF in Palestine.

Profile of cystic fibrosis in a single referral center in Egypt

It was generally believed that Cystic fibrosis (CF) is rare among Arabs; however, the few studies available from Egypt and other Arabic countries suggested the presence of many undiagnosed patients. The aim of the present study was to determine the frequency of CF patients out of the referred cases in a single referral hospital in Egypt. A total of 100 patients clinically suspected of having CF were recruited from the CF clinic of the Allergy and Pulmonology Unit, Children's Hospital, Cairo University, Egypt, throughout a 2 year period. Sweat chloride testing was done for all patients using the Wescor macroduct system for collection of sweat. Quantitative analysis for chloride was then done by the thiocyanate colorimetric method. Patients positive for sweat chloride (⩾60 mmol/L) were tested for the ΔF508 mutation using primer specific PCR for cystic fibrosis transmembrane conductance regulator (CFTR) gene. Thirty-six patients (36%) had a positive sweat chloride test. The main clinical presentations in patients were chronic cough in 32 (88.9%), failure to thrive in 27 (75%), steatorrhea in 24 (66.7%), and hepatobiliary involvement in 5 (13.9%). Positive consanguinity was reported in 50% of CF patients. Thirty-two patients were screened for ΔF508 mutation. Positive ΔF508 mutation was detected in 22 (68.8%) patients, 8 (25%) were homozygous, 14 (43.8%) were heterozygous, and 10 (31.3%) tested were negative. CF was diagnosed in more than third of patients suspected of having the disease on clinical grounds. This high frequency of CF among referred patients indicates that a high index of suspicion and an increasing availability of diagnostic tests lead to the identification of a higher number of affected individuals.

Changes in cystic fibrosis mortality in Australia, 1979-2005

OBJECTIVE

To assess mortality trends among people with cystic fibrosis (CF) in Australia.

DESIGN AND SETTING

We augmented Australian summary data for deaths from CF registered during 1979-2005 with information from Australian transplant centres on lung transplantation among CF patients for 1989-2005 to allow us to follow trends in all "mortality events" (death or lung transplantation).

MAIN OUTCOME MEASURE

Age at death or lung transplantation.

RESULTS

Between 1979 and 2005, the mean age at death increased from 12.2 years to 27.9 years for males and from 14.8 years to 25.3 years for females. Overall, female deaths in childhood (0-14 years) occurred at an age-standardised rate of 0.40 per 100,000 (95% CI, 0.34-0.45) during 1979-2005, which exceeded the corresponding rate for males of 0.24 (95% CI, 0.20-0.28) per 100,000. Among 0-14-year-old boys, event rates declined markedly after 1989, but they declined later and more gradually for girls, with the result that the age-standardised rate for girls was 2.38 times that of boys during 1989-2005 (95% CI, 1.69-3.36).

CONCLUSIONS

The pattern of CF mortality in Australia has changed substantially. Mortality rates continue to be higher for girls than for boys, but death in childhood has become uncommon. Survival has increased since 1979, but females continue to have reduced length of life.

Mutational spectrum of cystic fibrosis in the Lebanese population

BACKGROUND

Cystic fibrosis (CF) is the most common autosomal recessive disease in Caucasians; it is however, considered to be rare in the Arab populations. Reports of the cystic fibrosis transmembrane regulator (CFTR) mutations from Arabs, especially from the Lebanese population, are limited.

METHODS

Twenty-two unrelated Lebanese families, with at least one child with CF, were studied. DNA extracts from blood samples of patients and parents were screened for CFTR gene mutations.

RESULTS

Eleven different mutations were identified. Of the 44 alleles studied, the most common mutations were: F508del (34%), N1303K (27%), W1282X (7%), and S4X (7%). Five mutations - not previously reported in the Lebanese population - were identified; these are: S549N, G542X, 2043delG, 4016insG, and R117H-7T.

CONCLUSIONS

The most common CFTR mutations in addition to five mutations not previously described in the Lebanese population were identified. Identification of CFTR mutations in the Lebanese population is important for molecular investigations and genetic counseling.

Identification and characterization of CFTR gene mutations in Indian CF patients

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This study was performed on Indian CF patients (n = 50) to investigate the spectrum of mutations in the CFTR gene and their association with intragenic and extragenic marker haplotypes. We report identification of 14 previously known and eight novel mutations, namely 3986-3987delC, 876-6del4, 1792InsA, L69H, S158N, Q493L, I530L and E1329Q. The frequency of delta F508 was found to be 27%. Absolute linkage between delta F508 and the KM.19-GATT-TUB9-M470V-T854T haplotype (2-2-1-1-1) predicts a relatively recent appearance of delta F508 in Indian CF patients. Low frequency of delta F508 mutation and detection of eight novel and thirteen rare mutations reflect a heterogeneous spectrum of mutations in Indian CF patients. Failure to detect mutations in 34% of alleles indicates the possible presence of gross deletions involving one or more exons or may indicate the location of the molecular defects in either the noncoding parts of the gene or in the promoter region, which warrants analysis of those regions.

Jordan: communities and community genetics

The population in Jordan mounted from half a million in 1952 to 5.3 millions in 2004 and is composed of a variety of ethnic groups, the majority being Arabs. Couples nowadays tend to have fewer children, with the total fertility rate falling from 7.4 in 1976 to 3.7 in 2004. Consanguineous marriages are traditionally favored, with the preferred marriage partner being the offspring of the father's brother. First-cousin marriages declined from 28.5% for marriages contracted between 1950 and 1979 to 19.5% for marriages contracted after 1980. In the overall population, carrier rates for beta-thalassemia, alpha-thalassemia and sickle cell anemia are in the range of 2-4%, 3.2-12% of males have glucose-6-phosphate dehydrogenase deficiency, and the prevalences for familial Mediterranean fever and cystic fibrosis were estimated at around 0.04% each. A mandatory premarital screening program for beta-thalassemia carriers commenced in June 2004. The high consanguinity rate and the large family size in Jordan have contributed to the description of a number of rare and new autosomal recessive conditions. Genetic services in Jordan are still scarce and do not cover all the country due to the major impediments of a paucity of resources and trained health professionals in the area of medical genetics. The demographic data suggest that the health system in Jordan is capable of introducing some basic community genetic services into the primary health care program through comprehensive and cost-effective programs.

Cystic fibrosis detection in high-risk Egyptian children and CFTR mutation analysis

BACKGROUND

Knowledge about Cystic Fibrosis (CF) in Egypt is very limited. The objective of this study was to screen for CF in Egyptian children with suggestive clinical features and to identify causative genetic mutations.

METHODS

Sixty-one patients from the Chest Unit, Cairo University Children's Hospital, Egypt, were included. Subjects presented with persistent or recurrent respiratory symptoms, failure to thrive, diarrhea and/or steatorrhea and unexplained persistent jaundice. Patients were screened using the CF Indicatortrade mark sweat test system (PolyChrome Medical, Inc., Brooklyn Center, MN). A quantitative sweat testing was conducted on 10 of the 12 positive patients. Seven probands and one sibling underwent molecular analysis by direct DNA sequencing of the coding region and of the intronic sequences adjacent to the 27 exons of the CFTR gene.

RESULTS

Of 61 patients, 12 (20%) had positive sweat chloride screening. Ten of the 12 patients underwent quantitative sweat testing and were positive. Eight CFTR sequence changes were identified in seven affected probands and two were confirmed in one sibling by direct DNA sequencing.

CONCLUSION

The study results suggest that CF is more common in Egypt than previously anticipated. Larger studies are warranted to identify the incidence, molecular basis and clinical pattern of CF in the Egyptian population.

An Egyptian Infant with Cystic Fibrosis Mutation N1303K

An Egyptian infant with the common CFTR mutation N1303K in exon 21 developed alkalosis, electrolyte disturbance and pancreas insufficiency. The need is emphasized to consider the possibility of cystic fibrosis (CF) in the Arab world. The frequency of N1303K mutation in the Middle East and its distribution are both reviewed.

Cystic fibrosis in a child from Syria

We describe a Syrian child with typical features of severe cystic fibrosis (CF) phenotype and a positive sweat test. DNA analysis confirmed homozygosity for the delta F508 mutation on chromosome 7. This report stresses the need to draw attention to and consider CF in Arab populations. The frequency and distribution of delta F508 in the Middle East are reviewed.