Genetic Testing in Egyptian Patients with Inborn Errors of Immunity: a Single-Center Experience.

BACKGROUND: Inborn errors of immunity (IEI) are a group of heterogeneous disorders with geographic and ethnic diversities. Although IEI are common in Egypt, genetic diagnosis is limited due to financial restrictions. This study aims to characterize the genetic spectrum of IEI patients in Egypt and highlights the adaptation of the molecular diagnostic methods to a resource-limited setting. METHODS: Genetic material from 504 patients was studied, and proper diagnosis was achieved in 282 patients from 246 families. Mutational analysis was done by Sanger sequencing, next-generation sequencing (NGS) targeting customized genes panels, and whole-exome sequencing (WES) according to the patients' phenotypes and availability of genetic testing. RESULTS: A total of 194 variants involving 72 different genes were detected with RAG1/2 genes being the most encountered followed by DOCK8, CYBA, LRBA, NCF1, and JAK3. Autosomal recessive (AR) inheritance was detected in 233/282 patients (82.6%), X-linked (XL) recessive inheritance in 32/282 patients (11.3%), and autosomal dominant (AD) inheritance in 18/282 patients (6.4%), reflecting the impact of consanguineous marriages on the prevalence of different modes of inheritance and the distribution of the various IEI disorders. CONCLUSION: The study showed that a combination of Sanger sequencing in selected patients associated with targeted NGS or WES in other patients is an effective diagnostic strategy for IEI diagnosis in countries with limited diagnostic resources. Molecular testing can be used to validate other nonexpensive laboratory techniques that help to reach definitive diagnosis and help in genetic counseling and taking proper therapeutic decisions including stem cell transplantation or gene therapy.

MHC-II Deficiency Among Egyptians: Novel Mutations and Unique Phenotypes.

BACKGROUND: MHC class II deficiency leads to defective CD4+ T-cell function that results from impaired antigen presentation. A genetic disorder in 1 of 4 genes results in this syndrome that is associated with the clinical phenotype of combined immunodeficiency. OBJECTIVE: To describe the clinical, immunological, and molecular characteristics of 10 Egyptian patients from 9 different families having presented with MHC class II deficiency between 2012 and 2017. METHODS: An initial diagnosis based on the combination of clinical features and low HLA-DR expression by flow cytometry was confirmed by genetic analyses. RESULTS: Symptoms included failure to thrive (n = 9), persistent diarrhea (n = 5), and pneumonia (n = 8). Septicemia due to coagulase-negative staphylococci (n = 1) and Candida krusei (n = 1) was diagnosed. Nine patients orally received the live attenuated polio vaccine, of whom 3 developed acute flaccid paralysis thereafter. Nine patients received the BCG vaccine and none developed obvious signs of BCGitis. Four patients carried RFXANK gene mutations, 3 carried RFX5 gene mutations, 1 carried a CIITA gene mutation, and none carried RFXAP gene mutations. Six of the 7 detected mutations were previously unreported mutations: c.431T>C, c.247_250delTCAG, and c.600delG in the RFXANK gene; c.116+1G>A and c.715C>T in the RFX5 gene; and c.929delA in the CIITA gene. CONCLUSIONS: Given that Egypt is a North African country with a high rate of consanguinity, MHC class II deficiency is not rare. However, the molecular defects differ from those reported in nearby countries. Early diagnosis must be based on suspicious clinical signs and laboratory diagnosis because the defect can be missed by T-cell receptor excision circles based on neonatal screening.

Diagnosis of DOCK8 deficiency using Flow cytometry Biomarkers: an Egyptian Center experience.

In the past few years, several genes were shown to be implicated in various forms of the Hyper Immunoglobulin E syndrome. The present study is the first to describe a cohort of DOCK8 deficiency patients from Egypt. The study included 15 patients with features of combined immunodeficiency (CID) suggestive of DOCK8 deficiency. Flow cytometry was used for evaluation of DOCK8 expression and studying different immunological characteristics of those patients including evaluation of Th17, Tregs, T and B lymphocytes differentiation and the effect of the DOCK8 deficiency on the activation of the STAT3. Diagnosis was confirmed by mutational analysis. Profound defects in Th17 cells and Tregs were observed in all patients with impaired STAT3 phosphorylation, indicating that DOCK8 plays a pivotal role in the STAT3 signaling pathway. These findings together with decrease in memory B cells and defective DOCK8 expression by flow cytometry can confirm the diagnosis.

Genetic Counseling in Primary Immunodeficiency Disorders: An Emerging Experience in Egypt.

BACKGROUND: Primary immunodeficiency disorders (PIDs) are a heterogeneous group of diseases of the immune system leading to life-threatening infections, and, unless urgently treated with immune reconstitution, patients do not usually survive. With the continuing progress in molecular diagnosis, many mutations have been described in more than 300 genes. Genetic counseling has recently been considered an essential part of the management of PIDs. This study presents the experience of genetic counseling services in the largest PID center in Egypt, and reports on our management plan and the impact of prenatal diagnosis (PND) on families. METHODS: Based on the biochemical and molecular diagnosis of index cases, PND was offered for 10 families in 12 subsequent pregnancies. Five different genes were sequenced by Sanger sequencing in fetal samples. RESULTS: Seven fetuses were either normal or were carriers, while five fetuses were affected and human leukocyte antigen typing was performed, seeking a suitably related donor for stem cell transplantation. CONCLUSION: In spite of the genetic heterogeneity behind PIDs, genetic counseling should play a critical role in the management and future decisions of affected families.