Genomic testing identifies monogenic causes in patients with very early-onset inflammatory bowel disease: a multicenter survey in an Iranian cohort.

Patients with very early-onset inflammatory bowel disease (VEO-IBD) may present because of underlying monogenic inborn errors of immunity (IEI). Strong differences have been observed in the causes of monogenic IBD among ethnic populations. This multicenter study was carried out on 16 Iranian patients with VEO-IBD. We reviewed clinical and basic immunologic evaluation including flow cytometry and immunoglobulin levels. All patients underwent clinical whole exome sequencing (WES). Sixteen patients (8 females and 8 males) with a median age of 43.5 months were enrolled. The median age at the onset of symptoms was 4 months. Most patients (12, 75%) had consanguineous parents. Chronic non-bloody diarrhea (13, 81.3%) and perianal diseases including perianal abscess (6, 37.5%), anal fissure (6, 37.5%), or anal fistula (2, 12.5%) were the most common manifestations. WES identified a spectrum of genetic variants in 13 patients (81.3%): IL10RB (6, 37.5%), MVK (3, 18.8%), and CASP8, SLC35C1, G6PC3, and IKBKB in 1 patient, respectively. In 3 patients (18.7%), no variant was identified. Flow cytometry identified a spectrum of abnormalities that helped to assess the evidence of genetic diagnosis. At the end of the survey, 3 (18.8%) patients were deceased. This high rate of monogenic defects with a broad spectrum of genes reiterates the importance of investigating IEI in patients with infantile-onset IBD.

Allogenic hematopoietic stem cell transplantation in an Iranian patient with osteopetrosis caused by carbonic anhydrase II deficiency: A case report.

BACKGROUND: Osteopetrosis is a group of geneticall heterogeneous disorders resulting from impaired osteoclast function and bone resorption. The identification of specific genetic mutations can yield important prognostic and therapeutic implications. Herein, we present the diagnosis and successful application of hematopoietic stem cell transplantation (HSCT) in a patient with osteopetrosis caused by carbonic anhydrase II deficiency (Intermediate osteopetrosis). CASE PRESENTATION: Herein, we describe a 2.5-year-old male patient born to consanguineous parents who presented at 8-month-old with hydrocephaly, brain shunt, and developmental delay. Later at 9 months old, he was found to have eye disorder such as nystagmus, fracture of the elbow, abnormal skeletal survey, normal cell blood count (CBC), and severe hypocellularity in the bone marrow. Further evaluation showed renal tubular acidosis type 2. Whole-exome sequencing revealed a pathogenic homozygous variant in intron 2 of the carbonic anhydrase 2 gene (CA2) gene (c.232 + 1 G>T). The diagnosis of intermediate autosomal recessive osteopetrosis was established, and allogenic HSCT from his mother, a full-matched related donor (MRD), was planned. The conditioning regimen included Busulfan, Fludarabine, and Rabbit anti-thymocyte globulin. Cyclosporine and Mycophenolate Mofetil were used for graft-versus-host-disease prophylaxis. He Engrafted on day +13, and 95% chimerism was achieved. He is currently doing well without immunosuppressive therapy, now 12 months post HSCT, with normal calcium level and improving visual quality and FISH analysis revealed complete donor chimerism. DISCUSSION: HSCT could be a promising curative treatment for intermediate osteopetrosis and can provide long-term survival. Ongoing challenges in various aspects of HSCT remain to be addressed.

Molecular characterization of a large cohort of mucopolysaccharidosis patients: Iran Mucopolysaccharidosis RE-diagnosis study (IMPRESsion).

Mucopolysaccharidoses (MPSs) are rare, heterogeneous inborn errors of metabolism (IEM) diagnosed through a combination of clinical, biochemical, and genetic investigations. The aim of this study was molecular characterization of the largest cohort of Iranian MPS patients (302 patients from 289 unrelated families), along with tracking their ethnicity and geographical origins. 185/289 patients were studied using an IEM-targeted NGS panel followed by complementary Sanger sequencing, which led to the diagnosis of 154 MPS patients and 5 non-MPS IEMs (diagnostic yield: 85.9%). Furthermore, 106/289 patients who were referred with positive findings went through reanalysis and confirmatory tests which confirmed MPS diagnosis in 104. Among the total of 258 MPS patients, 225 were homozygous, 90 harbored novel variants, and 9 had copy number variations. MPS IV was the most common type (34.8%) followed by MPS I (22.7%) and MPS VI (22.5%). Geographical origin analysis unveiled a pattern of distribution for frequent variants in ARSB (c.430G>A, c.962T>C [p.Leu321Pro], c.281C>A [p.Ser94*]), GALNS (c.319G>A [p.Ala107Thr], c.860C>T [p.Ser287Leu], c.1042A>G [p.Thr348Ala]), and IDUA (c.1A>C [p.Met1Leu], c.1598C>G [p.Pro533Arg], c.1562_1563insC [p.Gly522Argfs*50]). Our extensive patient cohort reveals the genetic and geographic landscape of MPS in Iran, which provides insight into genetic epidemiology of MPS and can facilitate a more cost-effective, time-efficient diagnostic approach based on the region-specific variants.

Clinical, immunological, molecular and therapeutic findings in monogenic immune dysregulation diseases: Middle East and North Africa registry.

Monogenic immune dysregulation diseases (MIDD) are caused by defective immunotolerance. This study was designed to increase knowledge on the prevalence and spectrum of MIDDs, genetic patterns, and outcomes in Middle East and North Africa (MENA). MIDD patients from 11 MENA countries (Iran, Turkey, Kuwait, Oman, Algeria, Egypt, United Arab Emirates, Tunisia, Jordan, Qatar, and Azerbaijan) were retrospectively evaluated. 343 MIDD patients (58% males and 42% female) at a median (IQR) age of 101 (42-192) months were enrolled. The most common defective genes were LRBA (23.9%), LYST (8.2%), and RAB27A (7.9%). The most prevalent initial and overall manifestations were infections (32.2% and 75.1%), autoimmunity (18.6% and 41%), and organomegaly (13.3% and 53.8%), respectively. Treatments included immunoglobulin replacement therapy (53%), hematopoietic stem cell transplantation (HSCT) (14.3%), immunosuppressives (36.7%), and surgery (3.5%). Twenty-nine (59.2%) patients survived HSCT. Along with infectious complications, autoimmunity and organomegaly may be the initial or predominant manifestations of MIDD.

Identifying Novel Mutations in Iranian Patients with LPS-responsive Beige-like Anchor Protein (LRBA) Deficiency.

LPS-responsive beige-like anchor protein (LRBA) deficiency is a monogenic primary immunodeficiency characterized by a heterogeneous spectrum of clinical manifestations associated with immune dysregulation. In this study, we reported clinical, immunologic, and genetic evaluation of two Iranian patients from unrelated families, both suffering from recurrent respiratory tract infections, failure to thrive, interstitial lung disease, autoimmune cytopenia, and hypogammaglobulinemia. Pulmonary abscess in one patient and persistent enteropathy in another were also observed. Further investigations revealed causative mutations in the exon (c.2166_2766del) and intron (c.4730-3 T > G) of the LRBA gene. These results may provide further elucidation of the clinical phenotypes and responsible genetic factors of LRBA deficiency.

Case reports of juvenile GM1 gangliosidosisis type II caused by mutation in GLB1 gene.

BACKGROUND: Type II or juvenile GM1-gangliosidosis is an autosomal recessive lysosomal storage disorder, which is clinically distinct from infantile form of the disease by the lack of characteristic cherry-red spot and hepatosplenomegaly. The disease is characterized by slowly progressive neurodegeneration and mild skeletal changes. Due to the later age of onset and uncharacteristic presentation, diagnosis is frequently puzzled with other ataxic and purely neurological disorders. Up to now, 3-4 types of GM1-gangliosidosis have been reported and among them type I is the most common phenotype with the age of onset around 6 months. Various forms of GM1-gangliosidosis are caused by GLB1 gene mutations but severity of the disease and age of onset are directly related to the position and the nature of deleterious mutations. However, due to its unique genetic cause and overlapping clinical features, some researchers believe that GM1 gangliosidosis represents an overlapped disease spectrum instead of four distinct types. CASE PRESENTATION: Here, we report a less frequent type of autosomal recessive GM1 gangliosidosis with perplexing clinical presentation in three families in the southwest part of Iran, who are unrelated but all from "Lurs" ethnic background. To identify disease-causing mutations, Whole Exome Sequencing (WES) utilizing next generation sequencing was performed. Four patients from three families were investigated with the age of onset around 3 years old. Clinical presentations were ataxia, gate disturbances and dystonia leading to wheelchair-dependent disability, regression of intellectual abilities, and general developmental regression. They all were born in consanguineous families with no previous documented similar disease in their parents. A homozygote missense mutation in GLB1 gene (c. 601 G > A, p.R201C) was found in all patients. Using Sanger sequencing this identified mutation was confirmed in the proband, their parents, grandparents, and extended family members, confirming its autosomal recessive pattern of inheritance. CONCLUSIONS: Our study identified a rare pathogenic missense mutation in GLB1 gene in patients with complex neurodevelopmental findings, which can extend the list of differential diagnoses for childhood ataxia in Iranian patients.

Inflammatory myofibroblastic tumor of the pericardium in an 11-month-old infant: A case report.

Primary cardiac tumors are very rare in infants. Here we present an 11-month-old infant with a pericardial inflammatory myofibroblastic tumor who presented with symptoms of respiratory distress and cardiac tamponade. The tumor was surgically removed, and the patient received medical treatment; the patient had no problem with follow-up.

Successful Hematopoietic Stem Cell Transplant in a Patient with Omenn Syndrome: A Case Report.

Omenn syndrome is a rare subtype of severe combined immunodeficiency. Affected patients present recurrent infections, lymphadenopathy, skin eruptions, eosinophilia, hepatosplenomegaly, failure to thrive, and gastrointestinal complications with variable severity. A 3-month-old female infant, born to consanguineous healthy parents, presented with splenomegaly, erythroderma, failure to thrive, and history of recurrent otitis media, hypothyroidism, and Bacille Calmette-Guérin lymphadenitis following Bacille Calmette-Guérin vaccination.The immunologic workup showed lymphopenia; low levels of CD3+ T cells, CD4+ T cells, and CD8+ T cells; normal levels of CD19+ B cells and CD16+/CD56+ natural killer cells; hypogammaglobulinemia; and a high level of serum immunoglobulin E. She was clinically diagnosed with T-B+NK+ severe combined immunodeficiency. Genetic study revealed a missense homozygous alteration (c.617G>A, p.Arg206Gln) in exon 5 of the IL7R gene in the patient, as well as carrier states for the same variant in both parents. The patient received a peripheral blood stem cell transplant from a matched unrelated donor. A reduced intensity conditioning regimen was applied, including fludarabine, melphalan, rabbit antithymocyte globulin, and graft- versus-host disease prophylaxis by cyclosporine and mycophenolate mofetil. She clinically improved, and after engraftment the donor chimerism was 100% at 1 year after transplant. Hematopoietic stem cell transplantis a curative therapeutic option for patients with Omenn syndrome and, when combined with an early diagnosis, can prevent complications and improve patient survival.

Allogenic Hematopoietic Stem Cell Transplant in Iranian Patients With Congenital Sideroblastic Anemia: A Single-Center Experience.

Congenital sideroblastic anemia is characterized by anemia and intramitochondrial iron accumulation in erythroid precursors that form ring sideroblasts. The most common recessive forms are caused by sequence variations in the ALAS2 and SLC25A38 genes. In patients with transfusion-dependent and pyridoxine- resistant severe congenital sideroblastic anemia, hematopoietic stem celltransplantis the only curative option. Herein, we described successful implementations of allogeneic hematopoietic stem cell transplant in 4 Iranian children with congenital sideroblastic anemia. The patients had presented with clinical manifestations of anemia early in life, and the diagnoses of congenital sideroblastic anemia were established through blood tests and bone marrow aspiration. Congenital sideroblastic anemia was further confirmed by the identification of pathogenic variants in SLC25A38 in 2 patients. All 4 patients received allogeneic hematopoietic stem cell transplant with myeloablative conditioning regimen that included busulfan, cyclophosphamide, andrabbit antithymocyte globulin. A combination of cyclosporine A and methotrexate or mycophenolate mofetil was used for graft-versus-host disease prophylaxis. Bone marrow and peripheral blood from sibling or related donors with fully matched human leukocyte antigen profiles were applied. The outcomes of hematopoietic stem celltransplantin patients with congenital sideroblastic anemia were favorable. Three patients achieved full donor chimerism (>95%, 98%, and 100%), and the other patient showed mixed chimerism (75%). All patients remained transfusion independent. Hemato- poietic stem celltransplantis a curative treatmentthat can provide long-term survival for patients with congenital sideroblastic anemia, particularly when used in a timely manner. There remain ongoing challenges in various aspects of hematopoietic stem celltransplantin patients with congenital sideroblastic anemia, which remain to be elucidated.

Endogenous Bacteremia Caused by Intestinal Colonization of Carbapenem-Resistant Enterobacteriaceae (CRE) in Immunocompromised Children.

OBJECTIVE: Carbapenem-resistant Enterobacteriaceae (CRE) infection is life-threatening, especially for immunocompromised children. The source tracking of CRE could prevent bacteremia during hospitalization. In this study, the intestinal colonization of CRE and their translocation to blood were investigated. METHODS: Stool samples from immunocompromised pediatric patients were collected after admission, and secondary stool and blood samples were collected in case of fever. After CRE phonotypic detection, the OXA-48, NDM-1, VIM, IMP, and KPC genes were detected by PCR. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) was used to determine the phylogenic relatedness of the blood and fecal isolates. RESULTS: Bacteremia was recorded in 71.4% of the patients. Enterobacteriaceae spp. were recorded in 100% of the stool samples and 31% of the blood samples. The correlation between the length of stay (LOS), days of fever, chemotherapy regimens, and death rate was significant (p-value ≤ 0.05). OXA-48 was present in all CRE isolates in both the primary and the secondary stool samples and the blood samples. According to the phylogenetic data, 58.33% of the patients with bacteremia had identical blood and stool isolates. The death rate was 24.4% in children with CRE bacteremia. CONCLUSIONS: The primary intestinal colonization with CRE in immunocompromised pediatrics and their translocation to blood was established in this study. The implementation of infection control programs and the application of infection prevention strategies for immunocompromised children is necessary.

New Presentation of CD27 Deficiency; Coronary Ectasia and COVID-19.

CD27 is a costimulatory receptor involved in the maturation of the innate and adaptive immunity. CD27, through interaction with CD70, plays a role in the control of Epstein-Barr virus (EBV) infection. CD27 deficiency leads to an immune dysregulation disease characterized by EBV susceptibility. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might put patients with primary immunodeficiency at risk for adverse outcomes. Chromogenic in situ hybridization (CISH) study was performed to detect EBV in the lymphoma tissue. Genetic analysis of the patient was done with Whole Exome Sequencing and detected variant was confirmed with PCR-Sanger sequencing. Here we report a 20-month-old boy with CD27 deficiency who developed lymphoma and coronary artery ectasia and had been infected with SARS-CoV-2. Clinical and laboratory findings were incompatible with atypical Kawasaki syndrome or multisystem inflammatory syndrome in children (MIS-C). As CD27 deficiency is a rare immune defect, publishing clinical data about the identified patient(s) can shed light on our knowledge about the related phenotype and the spectrum of clinical manifestations associated with CD27 deficiency. Thus, our findings expanded the spectrum of manifestations beyond EBV infection, highlighting this unusual cardiac sequela that could be related to EBV infection, lymphoma, or an underlying disease.

Primary hemophagocytic lymphohistiocytosis in Iran: report from a single referral center.

Hemophagocytic lymphohistiocytosis (HLH) is a rare condition characterized by fever, hepatosplenomegaly, and cytopenia, and widespread accumulation of lymphocytes and histiocytes, sometimes with hemophagocytosis, primarily involving the spleen, lymph nodes, bone marrow, and liver. HLH can either occur sporadically (secondary HLH) or as part of a familial syndrome (primary HLH), including familial HLH and the distinct immunodeficiency syndromes. Herein the authors report 6 Iranian patients with primary HLH and their outcome from a single tertiary-care center.

Cernunnos defect in an Iranian patient with T- B+ NK+ severe combined immunodeficiency: A case report and review of the literature.

BACKGROUND: Defective Cernunnos gene in nonhomologous end-joining (NHEJ) pathway of the DNA repair is responsible for radiosensitive severe combined immunodeficiency (SCID). Herein, presented a new patient with Cernunnos deficiency and summarized the clinical, immunological, and molecular features of reported patients in the literature. CASE: The patient was a 6-month-old female born to consanguineous parents. She presented with long-lasting fever, diarrhea, poor feeding, and restlessness. She had suffered from recurrent fever of unknown origin and multiple episodes of oral candidiasis. In the physical examination, microcephaly, failure to thrive, oral candidiasis, pustular rash on fingers, and perianal ulcers, but no dysmorphic feature were observed. The immunologic workup revealed lymphopenia, neutropenia, normocytic anemia, low T- but normal B- and natural killer (NK)- cells, low immunoglobulin (Ig)G, and normal IgA, IgM, and IgE. The T-cell receptor excision circle (TREC) was low and the lymphocyte transformation test (LTT) was abnormal to mitogens and antigens. She was diagnosed with T- B+ NK+ SCID and improved by intravenous immunoglobulin along with antimicrobials. A homozygous splice site variant, c.390 + 1G > T, at the intron 3 of the NHEJ1, was identified and the diagnosis of Cernunnos deficiency was established. However, while a candidate for hematopoietic stem cell transplantation, she developed sepsis and died at 11 months of age. CONCLUSIONS: Cernunnos deficiency should be considered as a differential diagnosis in patients with microcephaly, growth retardation, recurrent infections, T-cell defects, and hypogammaglobulinemia. The normal B-cell level in the index patient is an unexpected finding in Cernunnos deficiency which requires further evaluation.

Case Report of a Novel NFkB Mutation in a Lymphoproliferative Disorder Patient.

BACKGROUND: Lymphoproliferative disorders include a heterogeneous list of conditions that commonly involve dysregulation of lymphocyte proliferation resulting in lymphadenopathy and bone marrow infiltration. These disorders have various presentations, most notably autoimmune manifestations, organomegaly, lymphadenopathy, dysgammaglobulinemia, and increased risk of chronic infections. CASE PRESENTATION: A young boy presented with symptoms overlapping different lymphoproliferative disorders, including episodes of chronic respiratory tract infections, dysgammaglobulinemia, lymphadenopathy-associated with splenomegaly as well as skin rashes. Genetic studies revealed multiple heterozygous variants, including a novel mutation in the NFκB1 gene. CONCLUSION: This novel mutation can reveal new aspects in the pathogenesis of lymphoproliferative disorders and propose new treatments for them.

Diversity of malignancies in patients with different types of inborn errors of immunity.

Genetic defects in the development, maturation, and/or function of the immune cells can lead to Inborn errors of immunity (IEI) which may predispose patients to malignancies. The overall risk for cancer in children with IEI ranges from 4 to 25% and the type of malignancy is highly dependent on the specific mutant gene underlying IEI. We investigated 3056 IEI patients registered in the Iranian national registry between the years 1999 and 2020 in this retrospective cohort study. The frequency of malignancy and its association with the type of IEI in these patients were evaluated. A total of 82 IEI patients with malignancy were enrolled in this study. Among them, predominantly lymphoma was the most common type of malignancy (67.1%), followed by leukemia (11%), and cancers of the head and neck (7.3%). Among identified lymphoma cancers, non-Hodgkin's lymphomas were the most frequent type (43.9%) followed by different subtypes of Hodgkin's lymphoma (23.2%). Solid tumors (18.3%) appeared to be very heterogeneous by type and localization. The correlation between the type of malignancy and survival status and the association between the type of malignancy and IEI entities were unremarkable. The awareness of the association between the presence of IEI and cancer highlights the importance of a synergistic effort by oncologists and immunologists in the early diagnosis of malignancy and personalized therapeutic strategies in IEI patients.

A 10-year single center survey of pediatric patients with histiocytic disorders in Iran.

Childhood histiocytosis is a rare and diverse group of proliferative disorders, characterized by accumulation and infiltration of antigen-presenting cells or antigen-processing cells, which can affect any tissue or organ. This study was performed in order to investigate the clinical characteristics of Iranian children with different types of histiocytic disorders. Thirty-five patients, with a median age of 3.5 years, who were referred and diagnosed with histiocytic disorders in a referral Children's Hospital in Iran from 1997-2006, were investigated in this study. According to the World Health Organization classification, 27 patients were in class 1, followed by 6 patients in class 2, and 1 patient in class 3. Moreover, 1 patient was diagnosed with sinus histiocytosis with massive lymphadenopathy. Bone lesions were the most common manifestation, which were detected in 15 cases, followed by skin lesions (11 cases) and fever (10 cases). Nonspecific findings like hepatomegaly and splenomegaly were found in 15 cases. Different types of treatment protocols were used according to the diverse groups of histiocytic disorders and different stages of disease, including surgical excision, radiotherapy, chemotherapy, and stem cell transplantation. Twelve patients did not respond well to the treatment and subsequently died due to complications of their disease. Although histiocytosis is considered a rare condition, it can be problematic for pediatric hematologists because of the unknown etiologies and pathogenesis, variable classifications and subtypes, diagnostic difficulties, poor therapeutic responses with high mortality, and some complications after different therapeutic protocols.

Development of secondary T-cell acute lymphoblastic leukemia in a child with hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a severe life-threatening disorder, characterized by hyperactivation of macrophages. A 12-year-old female was referred to our center; the diagnosis of HLH was made for the patient and immunosuppressive regimen was started. After a 2-year follow-up, the patient developed secondary T-cell acute lymphoblastic leukemia (T-ALL), confirmed by flow cytometric studies. Treatment was started based on T-ALL protocol, but the patient died because of relapse and sepsis. This case highlights the issue of secondary malignancy following HLH and demonstrates the need for continued follow-up in such patients.

Severe hypochromic microcytic anemia in a patient with congenital atransferrinemia.

Congenital atransferrinemia or hypotransferrinemia is a very rare autosomal recessive disorder, characterized by a deficiency of transferrin, resulting in hypochromic, microcytic anemia and hemosiderosis. The authors describe a 10-year-old Iranian girl with hypochromic microcytic anemia. The age presentation of anemia was 3 months. Further evaluations indicate severe hypochromic microcytic anemia with decreased serum levels of iron, TIBC, and increased serum level of ferritin in this patient. The serum level of transferrin was decreased. The diagnosis of atransferrinemia was confirmed. Although atransferrinemia is a rare condition, it should be considered in the cases with hypochromic microcytic anemia, decreased serum levels of iron, TIBC, and increased serum level of ferritin.

Rapid Desensitization for Hypersensitivity Reactions to Chemotherapeutic Drugs; A Case Series.

Usage of cancer chemotherapeutics drugs can be associated with adverse drug reactions. When IgE-mediated drug reactions are formed following administration of a chemotherapeutics drug that is a drug of choice, drug desensitization protocols can be helpful. HSR can be allergic or nonallergic, but the clinical manifestations are similar. RDD is effective when used appropriately, however it is often over utilized instead of performing a drug challenge. RDD is both an acceptable approach and a high-risk treatment modality in patients, in whom the offending agent is the first choice in chemotherapy. The safety of this modality has been acceptable in large studies. The side effects are often less frequent and less severe by repeating the protocol. We present 4 cases of successful desensitization in cancer patients, who have developed IgE- mediated reactions to their major chemotherapy drug.

Sensory neural hearing loss in beta-thalassemia major patients treated with deferoxamine.

This study evaluated the incidence of sensory neural hearing loss (SNHL) in beta-thalassemia major patients treated with deferoxamine in Mofid Children's Hospital. Based on the patients' file review, this descriptive and cross-sectional study was performed in all thalassemia patients older than 5 years old who were treated with regular blood transfusion and deferoxamine pump injection during the year 2006. The first visit with the otolaryngologist was performed in all patients to demarcate the presence of cerumen, otitis, and congenital abnormalities of ears. Then pure tone audiometery in frequency ranges of 250-8000 Hz was performed. Data statistical analysis was done by Mann-Whitney, chi square, and Fisher tests. There were 67 patients over 5 years old in our study. Five patients (7.4%), including 2 boys and 3 girls, in the age range of 7-24 years (mean:17.8 +/- 6.6 years) had SNHL. Their hearing loss was bilateral and in the frequency range of 2000-4000 Hz, with a mean of 3200 +/- 836.66 Hz. There were no significant differences between SNHL and non-SNHL patients in age, sex, serum ferritin level, age of the first transfusion, starting age of deferoxamine infusion, or duration and dosage of deferoxamine therapy. It seems that SNHL is not directly related to the serum ferritin level or deferoxamine dosage and other factors, including genetic or constitutional characteristics, may be also related. On the other hand, this complication may occur with doses lower than 50 mg/kg/day of deferoxamine, so no dosage can be considered safe for this drug. Despite the results of this study, hearing evaluation of beta-thalassemia major patients by audiometry is recommended because of the importance of this complication and the consequent disabilities.