Phenotypic and Genotypic Characterization of Hereditary Angioedema in Saudi Arabia.

Hereditary angioedema (HAE) is a potentially life-threatening autosomal dominant disorder affecting roughly 1:50,000 individuals. It is commonly characterized by swelling of the larynx, gastrointestinal tract, extremities, and skin. There is growing genetic heterogeneity associated with this disease but more than 95% of mutations are found in SERPING1, the gene which encodes complement 1 inhibitor (C1-INH). HAE cohorts from several populations have been published but no large scale study has been reported from the Arab world to date. Here we document the clinical and genetic findings of HAE patients from a single Saudi institution, which is a major referral center at the national level. A total of 51 patients across 17 unrelated families were recruited including two large multi-generational families, of which one contained an in-frame exonic deletion that was resolved through MLPA. Two cases were negative for all the genes we tested (including F12, PLG, ANGPT1, MYOF, KNG1, and HS3ST6). The predominant HAE subtype in our cohort was type I, at 76%. We were able to uncover a mutation in 49 patients (96%). No type III (normal C1-INH) patients were encountered in the clinic, suggesting that this subtype does not play a major role in HAE pathogenesis in Saudi Arabia. Additionally, the existence of four patients with consistently normal complement 4 (C4) levels alongside abnormal C1-INH profiles highlights the utility of dual screening for both proteins in suspected patients.

Loss of NHEJ1 Protein Due to a Novel Splice Site Mutation in a Family Presenting with Combined Immunodeficiency, Microcephaly, and Growth Retardation and Literature Review.

INTRODUCTION: Non-homologous end joining gene 1 (NHEJ1) defect is a rare form of primary immune deficiency. Very few cases have been described from around the world. PURPOSE: We are reporting the first family from the Arabian Gulf with three siblings presenting with combined immunodeficiency (CID), microcephaly, and growth retardation due to a novel NHEJ1 splice site mutation, in addition to a review of the previously published literature on this subject. METHODS: Patients' clinical, immunological, and laboratory features were examined. Samples were subjected to targeted next-generation sequencing (NGS). The pathogenic change in NHEJ1 was confirmed by Sanger sequencing, then further assessed at the RNA and protein levels. RESULTS: Patients were found to have a homozygous splice site mutation immediately downstream of exon 3 in NHEJ1 (c.390 + 1G > C). This led to two distinct mRNA products, one of which demonstrated skipping of the last 69 basepairs (bp) of exon 3 while the other showed complete skipping of the entire exon. Although both deletions were in-frame, immunoblotting did not reveal any NHEJ1 protein products in patient cells, indicating a null phenotype. CONCLUSION: Patients presenting with CID, microcephaly, and growth retardation should be screened for NHEJ1 gene mutations. We discuss our data in the context of one of our patients who is still alive at the age of 30 years, without transplantation, and who is the longest known survivor of this disease.

Novel mutation in DOCK8-HIES with severe phenotype and successful transplantation.

BACKGROUND: Hyper-IgE syndrome (HIES) due to DOCK8 deficiency is an autosomal recessive (AR) primary combined immunodeficiency which results in significant morbidity and mortality at a young age. Different mutations in the DOCK8 gene can lead to variable severity of the disease. OBJECTIVE: We evaluated the genetic mutations in three related patients with severe clinical manifestations suggestive of AR HIES. We also explored whether treatment with stem cell transplantation could lead to complete disease resolution. METHOD: We examined the clinical manifestations and immunological workup of these patients. Their DNA was also screened for causative mutation. Post transplantation, clinical and immunological data for the transplanted patient was also collected. RESULTS: All patients had a severe course of the disease with rarely reported severe complications in HIES. One patient died with lymphoma while another died with progressive multifocal leukoencephalopathy (PML) due to a slow virus. All our patients had two novel mutations in the DOCK8 gene. One of these mutations was a novel pathogenic mutation and explains the severity of the disease (homozygous splice site mutation at position 5 after the end of exon 45), while the other mutation was mostly non-pathogenic. Hematopoietic stem cell transplantation (HSCT) was performed in the youngest patient with excellent engraftment and full reversibility of the clinical manifestations. CONCLUSION: We report 3 patients from a consanguineous family diagnosed with AR-HIES due to a novel pathogenic mutation in DOCK8 gene leading to fatal outcome in 2 patients and complete resolution of the clinical and immunological features in the third patient by HSCT.

Unbiased targeted next-generation sequencing molecular approach for primary immunodeficiency diseases.

BACKGROUND: Molecular genetics techniques are an essential diagnostic tool for primary immunodeficiency diseases (PIDs). The use of next-generation sequencing (NGS) provides a comprehensive way of concurrently screening a large number of PID genes. However, its validity and cost-effectiveness require verification. OBJECTIVES: We sought to identify and overcome complications associated with the use of NGS in a comprehensive gene panel incorporating 162 PID genes. We aimed to ascertain the specificity, sensitivity, and clinical sensitivity of the gene panel and its utility as a diagnostic tool for PIDs. METHODS: A total of 162 PID genes were screened in 261 patients by using the Ion Torrent Proton NGS sequencing platform. Of the 261 patients, 122 had at least 1 known causal mutation at the onset of the study and were used to assess the specificity and sensitivity of the assay. The remaining samples were from unsolved cases that were biased toward more phenotypically and genotypically complicated cases. RESULTS: The assay was able to detect the mutation in 117 (96%) of 122 positive control subjects with known causal mutations. For the unsolved cases, our assay resulted in a molecular genetic diagnosis for 35 of 139 patients. Interestingly, most of these cases represented atypical clinical presentations of known PIDs. CONCLUSIONS: The targeted NGS PID gene panel is a sensitive and cost-effective diagnostic tool that can be used as a first-line molecular assay in patients with PIDs. The assay is an alternative choice to the complex and costly candidate gene approach, particularly for patients with atypical presentation of known PID genes.

First study of pattern of anaphylaxis in a large tertiary care hospital in Saudi Arabia.

BACKGROUND: Anaphylaxis is a serious allergic reaction that may cause death. The signs and symptoms of anaphylaxis have not been examined in the Saudi population before. OBJECTIVE: The present study examined the signs, symptoms, triggers, and demographic patterns of patients treated for anaphylaxis at a large tertiary care hospital in Riyadh, Saudi Arabia. METHODS: All the patients who were prescribed new prescriptions of adrenaline auto-injectors (AAs) between February 1, 2010 and December 31, 2011 were included in this study. Information was collected using a standardized form. RESULTS: There were 238 patients who were analyzed. The median age at the time of first AA prescription was 15.5 years. Female to male ratio was 52:48 and 54% of the subjects were more than 18 years of age. There were some differences in the presenting signs and symptoms observed in our study compared with similar studies from around the world. Urticaria and angioedema were the most common at about 70% across all ages, followed by shortness of breath at 28%. Some triggers were found to be more common in our region. Food was the commonest trigger for anaphylaxis including tree nuts, egg, and sesame. Drug allergy was also a common trigger, with penicillins and nonsteroidal anti-inflammatory drugs being the commonest. Regarding insect allergy, samsam ant was the commonest trigger in our study. CONCLUSION: To our knowledge, this is the first study on anaphylaxis in Saudi Arabia. Some of the manifestations of anaphylaxis are significantly different in our population study compared to previously published data from other parts of the world. While managing anaphylaxis, we should be mindful of these differences. This improved understanding should help reduce the morbidity and mortality associated with anaphylaxis in our region.

Primary Immunodeficiency Diseases in Saudi Arabia: a Tertiary Care Hospital Experience over a Period of Three Years (2010-2013).

PURPOSE: Primary immunodeficiencies (PID) are a group of heterogeneous diseases. Epidemiological studies from databases worldwide show geographical variation. In this study the objective is to determine the spectrum of PID in Saudi Arabia by analyzing the database in a referral tertiary hospital. METHODS: This is a prospective data collection by interviews and medical chart review for all PID patients followed at the King Faisal Specialist Hospital & Research Center (KFSH&RC) from May 2010 to April 2013. RESULTS: A total of 502 patients presented (53 % male and 47 % female). Combined immunodeficiencies were the most common (59.7 %), followed by predominantly antibody deficiencies (12.3 %), congenital defects of phagocyte (9.4 %), combined immunodeficiencies with associated or syndromic features (6.2 %), disease of immune dysregulation (6 %), complement deficiencies (5.8), and defects in innate immunity (0.6 %). The most common combined immunodeficiencies phenotype was T-B-SCID (17 %). The patients' ages ranged from less than 1 year old to 78 years, and 394 patients (78.2 %) are in the paediatrics age group (<14 years). The overall mean age of symptoms onset was 17 months and the overall mean delay in diagnosis was 21.6 months. Recurrent infections were the most common occurring clinical presentation (66 %), followed by family history (26 %). Consanguinity was found in 75 % of the patients. A total of 308 (61 %) patients had undergone stem cell transplantation (SCT). CONCLUSION: The study revealed that combined immunodeficiencies are not uncommon and are the most frequent occurring diagnosis in our patient population. This study is a prerequisite to establish a national registry of primary immunodeficiency in Saudi Arabia.

Autoimmune polyglandular syndrome type 1 in Saudi children.

OBJECTIVE: To describe the clinical, biochemical, and immunological manifestations of autoimmune polyglandular syndrome type 1 (APS-1) in a Saudi population. METHODS: The medical files of 7 consanguineous Saudi families with 20 affected siblings were retrospectively reviewed. They were followed at the Pediatric Endocrinology Clinic, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia for a mean duration of 6 years (January 2000 to December 2009). The age of the affected children ranged from 2-17 years. The included patients had at least 2 out of the 3 major clinical diagnostic criteria of APS-1. RESULTS: Fourteen children had neonatal chronic mucocutaneous candidiasis affecting the nails and mouth. The most commonly presenting endocrine disease among APS-1 patients was hypoparathyroidism. Eight patients had autoimmune Addison's disease. Hypothyroidism was diagnosed in 3 patients, and 9 patients had alopecia universalis. Other endocrine and autoimmune disorders were infrequently seen including type 1 diabetes, growth hormone deficiency, celiac disease, autoimmune hepatitis, and keratoconjuctivitis. CONCLUSION: Autoimmune polyglandular syndrome type 1, although an uncommon disorder in Saudi children affects multiple endocrine glands, and is associated with several autoimmune diseases where alopecia universalis is a common finding.

Novel and recurrent mutations in the C1NH gene of Arab patients affected with hereditary angioedema.

BACKGROUND: Autosomal dominant hereditary angioedema (HAE) results in episodes of subcutaneous edema in any body part and/or submucosal edema of the upper respiratory or gastrointestinal tracts. This disorder is caused by mutations in the C1NH gene, many of which have been described primarily in European patients. However, the genetic cause of HAE in Middle Eastern Arab patients has not yet been determined. METHODS: Four unrelated Arab families, in which 15 patients were diagnosed with HAE, were studied. DNA from 13 patients was analyzed for mutations in the C1NH gene by DNA sequencing. RESULTS: Three novel and 2 recurrent mutations were identified in the C1NH gene of HAE patients. In family 1, the patient was heterozygous for a novel c.856C>T and a recurrent c.1361T>A missense mutation encoding for p.Arg264Cys and p.Val432Glu, respectively. In patients from family 2, a novel c.509C>T missense mutation encoding for a p.Ser148Phe was identified. In patients from family 3, a novel c.1142delC nonsense mutation encoding for a p.Ala359AlafsX15 was discovered. In family 4, a recurrent c.1397G>A missense mutation encoding for a p.Arg444His was present. CONCLUSION: This is the first ever report of C1NH gene mutations in Middle Eastern Arab patients. Our study suggests that, despite the numerous existing mutations in the C1NH gene, there are novel and recurrent mutations in HAE patients of non-European origin. We conclude that the spectrum of C1NH gene mutations in HAE patients is wider due to the likely presence of novel and recurrent mutations in patients of other ethnicities.