COVID-19-associated multisystem inflammatory syndrome in children: Experiences of three centres in Turkey.

BACKGROUND: The pathogenesis and clinical manifestations of the multisystem inflammatory syndrome in children (MIS-C) has not yet been fully elucidated and there is no clear consensus on its treatment yet. OBJECTIVES: To evaluate our patients diagnosed with MIS-C and present them to the literature in order to contribute to the better understanding of this new disease, which entered paediatric practice with the SARS-CoV-2 peak. METHODS: In this study, 17 MIS-C cases diagnosed according to the Centers for Disease Control and Prevention criteria were included. RESULTS: Of the patients, 7 (41.2%) had a comorbidity. Gastrointestinal system involvement was the most prominent in the patients (70.6%). Laparotomy was performed in 3 patients due to acute abdomen. Two patients had neurological involvement. Of the patients, 15 (88.2%) received intravenous immunoglobulin and 13 (76.5%) received both intravenous immunoglobulin and methylprednisolone. Two patients received invasive mechanical ventilation and 4 patients received high flow rate nasal cannula oxygen therapy. One of our patients who needed invasive mechanical ventilation and high vasoactive-inotrope support died despite all supportive treatments including plasmapheresis and extracorporeal membrane oxygenation. CONCLUSIONS: MIS-C picture can have a fatal course and may present with severe gastrointestinal and neurological signs. Unnecessary laparotomy should be avoided.

Missed Diagnosis of ß-Thalassemia Trait in Premarital Screening Due to Accompanying HbA2-Yialousa (HBD: c.82G>T).

The diagnosis of ß-thalassemia (ß-thal) trait is usually based on an elevated HbA2 fraction (3.5% to 8%). Co-inheritance of a δ-globin variant along with ß-globin gene defects can interfere with the diagnosis of ß-thal trait by causing normal HbA2 levels. In this report, we present an infant with ß-thal major whose mother's ß-thal trait was missed twice before due to an accompanying δ-globin mutation (HbA2-Yialousa; HBD: c.82G>T), resulting in a borderline HbA2 level. In an individual with microcytosis and hypochromia but an apparently normal HbA2 level, compound heterozygosity for a δ-globin mutation and a ß-thal mutation should be remembered in the differential diagnosis.

Association of CYP3A5 Expression and Vincristine Neurotoxicity in Pediatric Malignancies in Turkish Population.

Vincristine is a widely used chemotherapeutic agent in the treatment of childhood malignancies. Neuropathy is the most common adverse effect. CYP3A4 and CYP3A5 enzymes of cytochrome p450 enzyme system are responsible in vincristine metabolism. Genetic polymorphism may alter the vincristine metabolism and the neurotoxicity rate. In this study, distribution of CYP3A5 alleles among Turkish children with malignancies, relation between CYP3A5 genotype and neurotoxicity rates, as well as severity and duration of neuropathy and total vincristine doses were investigated. Patient group consisted of 115 patients (age, 1 to 17 y) with acute lymphoblastic leukemia and solid tumors, who were treated with vincristine consisting chemotherapy protocols. Control group consisted of 50 children without any neurological symptom or disorders. All patient files were reviewed for presence and severeness of neurotoxicity symptoms. Blood samples were obtained and CYP3A5 genotypes were analyzed. Neurotoxicity occurred in 20.8% of patients. Although it was found to occur more frequently after 4 doses of vincristine, and rates were higher in the low-dose vincristine group suggesting other contributing factors. Although neurotoxicity rate in the CYP3A5*1/*3 genotype was 17.6%, it was 21.6% in the CYP3A5*3/*3 genotype and the difference was not statistically significant (P<0.05). This study suggested that vincristine-related neurotoxicity is dose-independent and genotype is not the only causative factor in the occurrence of neurotoxicity in these patients.

Iron-refractory iron deficiency anemia.

Iron is essential for life because it is indispensable for several biological reactions, such as oxygen transport, DNA synthesis, and cell proliferation. Over the past few years, our understanding of iron metabolism and its regulation has changed dramatically. New disorders of iron metabolism have emerged, and the role of iron as a cofactor in other disorders has begun to be recognized. The study of genetic conditions such as hemochromatosis and iron-refractory iron deficiency anemia (IRIDA) has provided crucial insights into the molecular mechanisms controlling iron homeostasis. In the future, these advances may be exploited to improve treatment of both genetic and acquired iron disorders. IRIDA is caused by mutations in TMPRSS6, the gene encoding matriptase-2, which downregulates hepcidin expression under conditions of iron deficiency. The typical features of this disorder are hypochromic, microcytic anemia with a very low mean corpuscular volume of erythrocytes, low transferrin saturation, no (or inadequate) response to oral iron, and only a partial response to parenteral iron. In contrast to classic iron deficiency anemia, serum ferritin levels are usually low-normal, and serum or urinary hepcidin levels are inappropriately high for the degree of anemia. Although the number of cases reported thus far in the literature does not exceed 100, this disorder is considered the most common of the "atypical" microcytic anemias. The aim of this review is to share the current knowledge on IRIDA and increase awareness in this field.

Functional and clinical impact of novel TMPRSS6 variants in iron-refractory iron-deficiency anemia patients and genotype-phenotype studies.

Iron-refractory iron-deficiency anemia (IRIDA) is a rare autosomal-recessive disorder characterized by hypochromic microcytic anemia, low transferrin saturation, and inappropriate high levels of the iron hormone hepcidin. The disease is caused by variants in the transmembrane protease serine 6 (TMPRSS6) gene that encodes the type II serine protease matriptase-2, a negative regulator of hepcidin transcription. Sequencing analysis of the TMPRSS6 gene in 21 new IRIDA patients from 16 families with different ethnic origin reveal 17 novel mutations, including the most frequent mutation in Southern Italy (p.W590R). Eight missense mutations were analyzed in vitro. All but the p.T287N variant impair matriptase-2 autoproteotylic activation, decrease the ability to cleave membrane HJV and inhibit the HJV-dependent hepcidin activation. Genotype-phenotype studies in IRIDA patients have been so far limited due to the relatively low number of described patients. Our genotype-phenotype correlation analysis demonstrates that patients carrying two nonsense mutations present a more severe anemia and microcytosis and higher hepcidin levels than the other patients. We confirm that TMPRSS6 mutations are spread along the gene and that mechanistically they fully or partially abrogate hepcidin inhibition. Genotyping IRIDA patients help in predicting IRIDA severity and may be useful for predicting response to iron treatment.

Factor 8 Gene Mutation Spectrum of 270 Patients with Hemophilia A: Identification of 36 Novel Mutations

Objective: Hemophilia A (HA) is the most severe X-linked inherited bleeding disorder caused by hemizygous mutations in the factor 8 (F8) gene. The aim of this study is to determine the mutation spectrum of the F8 gene in a large HA cohort from Turkey, and then to establish a phenotype-genotype correlation. Materials and Methods: All HA cases (270 patients) analyzed molecularly in the Ege University Pediatric Genetics Molecular Laboratory between March 2017 and March 2018 were included in this study. To identify intron 22 inversion (Inv22), intron 1 inversion (Inv1), small deletion/insertions, and point mutations, molecular analyses of F8 were performed using a sequential application of molecular techniques. Results: The mutation detection success rate was 95.2%. Positive Inv22 was found in 106 patients (39.3%), Inv1 was found in 4 patients (1.5%), and 106 different disease-causing sequence variants were identified in 137 patients (50.6%). In 10 patients (3.7%), amplification failures involving one or more exonic regions, considered to be large intragenic deletions, were identified. Of 106 different F8 mutations, 36 were novel. The relationship between F8 genotype and inhibitor development was considered significant. Conclusion: A high mutation detection rate was achieved via the broad molecular techniques applied in this study, including 36 novel mutations. With regard to mutation types, mutation distribution and their impact on clinical severity and inhibitor development were found to be similar to those previously reported in other hemophilia population studies.

Fatal Epstein-Barr virus infection in a case of familial hemophagocytic lymphohistiocytosis with syntaxin-11 mutation.

Familial hemophagocytic lymphohistiocytosis (FHL) is a fatal disease of early infancy caused by defective natural killer cell activity and is characterized by fever, organomegaly, pancytopenia, and coagulopathy. Disease-causing mutations have been found in perforin, Munc 13-4 and syntaxin-11 genes. We herein describe a case of late-onset FHL with syntaxin-11 mutation in a six-year-old boy in whom only partial response was obtained by immunochemotherapy (HLH-94 protocol) and who died with persistent Epstein-Barr virus (EBV) infection. The role of EBV infection in the prognosis of FHL is discussed.

An infant with an extremely rare cobalamin disorder: Methionine synthase deficiency and importance of early diagnosis and treatment.

Kasapkara ÇS, Yilmaz-Keskin E, Özbay-Hosnut F, Akçaboy M, Polat E, Olgaç A, Zorlu P. An infant with an extremely rare cobalamin disorder: Methionine synthase deficiency and importance of early diagnosis and treatment. Turk J Pediatr 2019; 61: 282-285. Functional methionine synthase deficiency can be separated into two classes, cobalamin (Cbl) deficiency type E (CblE) and type G (CblG), which are the result of mutations that affect methionine synthase reductase or methionine synthase, respectively. Deficiency of methionine synthase activity may result in megaloblastic anemia without methylmalonic aciduria and neuromuscular abnormality of varying severity. Delayed milestones, ataxia, cerebral atrophy, muscular hypotonia, neonatal seizures, and blindness have been reported as the associated clinical findings. Early diagnosis and treatment are crucial for a more favorable diagnosis of the affected cases. Herein we report a three-month-old boy with CblG disease who presented with failure to thrive, chronic diarrhea, feeding intolerance, oral ulcers, microcephaly and hypotonia, and showed a dramatic response to treatment. In the first few months of life, megaloblastic anemia accompanied by apparent neurological involvement should direct physicians to order examinations like measurement of total homocysteine and methylmalonic acid levels to detect possible forms of inherited Cbl intracellular metabolism disorders.

Hemolytic Uremic Syndrome in an Infant with Primary Hyperoxaluria Type II: An Unreported Clinical Association.

A 6-month-old boy presented with acute renal failure, thrombocytopenia, and severe non-immune hemolytic anemia. Infection by Shiga-like toxin-producing Escherichia coli and other causes of microangiopathic hemolysis were ruled out, leading to a diagnosis of atypical hemolytic uremic syndrome (aHUS). Neither pathogenic variants in HUS-associated genes nor anti-factor H antibodies were identified. Copy number variation analysis uncovered 4 copies of complement factor H related genes, CFHR1-CFHR4, conceivably leading to higher than normal levels of the corresponding proteins. However, this abnormality was also found in the healthy relatives, neither explaining the disease nor the excessive complement deposition on endothelial cells detected by an ex-vivo test. Whole-exome sequencing revealed a pathogenic homozygous variant in GRHPR encoding the glyoxylate and hydroxypyruvate reductase. Recessive GRHPR mutations cause primary hyperoxaluria type 2 (PH2). The presence of renal calculi in the patient and elevated oxalate levels in the urine were consistent with the genetic diagnosis of PH2. We hypothesize that, in this patient, hyperoxaluria caused by the GRHPR genetic defect triggered endothelial perturbation and complement activation, which was amplified by impaired factor H regulatory activity due to the increased -CFHR1-CFHR4 copy numbers, resulting in aHUS.

Neonatal tetanus in Turkey; what has changed in the last decade?

BACKGROUND: Neonatal tetanus (NT) is still considered as one of the major causes of neonatal death in many developing countries. The aim of the present study was to assess the characteristics of sixty-seven infants with the diagnosis of neonatal tetanus followed-up in the Pediatric Infectious Diseases Ward of Dicle University Hospital, Diyarbakir, between 1991 and 2006, and to draw attention to factors that may contribute (or may have contributed) to the elimination of the disease in Diyarbakir. METHODS: The data of sixty-seven infants whose epidemiological and clinical findings were compatible with neonatal tetanus were reviewed. Patients were stratified into two groups according to whether they survived or not to assess the effect of certain factors in the prognosis. Factors having a contribution to the higher rate of tetanus among newborn infants were discussed. RESULTS: A total of 55 cases of NT had been hospitalized between 1991 and 1996 whereas only 12 patients admitted in the last decade. All of the infants had been delivered at home by untrained traditional birth attendants (TBA), and none of the mothers had been immunized with tetanus toxoid during her pregnancy. Twenty-eight (41.8%) of the infants died during their follow-up. Lower birth weight, younger age at onset of symptoms and at the time admission, the presence of opisthotonus, risus sardonicus and were associated with a higher mortality rate. CONCLUSION: Although the number of neonatal tetanus cases admitted to our clinic in recent years is lower than in the last decade efforts including appropriate health education of the masses, ensurement of access to antenatal sevices and increasing the rate of tetanus immunization among mothers still should be made in our region to achieve the goal of neonatal tetanus elimination.

Association between Maternal and Infantile Markers of Cobalamin Status During the First Month Post-Delivery.

OBJECTIVE: Exclusively breast-fed infants born to vitamin B12 (cobalamin, cbl)-deficient mothers can develop symptoms within a few months following delivery. The authors aimed to assess the relationship between maternal and infantile markers of cbl status. METHODS: In 240 full-term infants (age, 2-30 d) admitted to Samsun Maternity and Child Health Hospital and their mothers, complete blood count testing and serum cbl, folate and plasma total homocysteine (tHcy) measurements were performed. In the mothers, serum ferritin and holotranscobalamin (holoTC) levels were measured additionally. RESULTS: Among the infants, 146 (60.8%) had cbl deficiency (serum cbl <259 pg/mL), whereas 184 (76.7%) mothers had a low cbl level (serum cbl <300 pg/mL). When cbl deficiency was defined as a serum holoTC level < 40 pmol/L, 152 (63.3%) mothers were found as deficient. In addition, 147 (61.3%) infants had an elevated tHcy level (>10 µmol/L), in 35 (23.8%) of these 147 infants tHcy level being markedly elevated (>20 µmol/L). None of the infants had folate deficiency. In the correlational analysis between maternal and infantile markers associated with cbl status, the strongest correlation was observed between maternal holoTC and infantile tHcy (r = -0.49, p < 0.001), followed by the correlation between maternal tHcy and infantile tHcy (r = 0.47, p < 0.001). The weakest correlations were found between maternal cbl and infantile cbl (r = 0.28, p < 0.001), and between maternal cbl and infantile tHcy (r = -0.25, p < 0.001). CONCLUSIONS: Maternal cbl status is an important determinant of infantile cbl status. Both maternal holoTC and tHcy may assist in predicting infantile cbl status. The finding of high prevalence of maternal and infantile cbl deficiency in this study points towards the need for effective strategies to prevent cbl deficiency in women prior to getting pregnant.

Is the acronym IRIDA acceptable for slow responders to iron in the presence of TMPRSS6 mutations?

Iron refractory iron deficiency anemia (IRIDA) is a recently described autosomal recessive disorder caused by mutations in TMPRSS6, the gene encoding matriptase-2. Patients have inappropriately high levels of hepcidin. Hypochromic microcytic anemia refractory to oral iron and only partially responsive to parenteral iron is the hallmark of this disorder. We report six patients from three unrelated families with mutations in the TMPRSS6 gene, with three of the four identified mutations being novel. Although response to oral iron in IRIDA patients has been reported rarely before, all of our five patients receiving oral iron and our one patient supplemented with vitamin C responded to therapy at least to some extent. We think that IRIDA should be considered in the differential diagnosis of patients with findings of iron deficiency anemia responding inadequately to oral iron, particularly in countries with a high rate of consanguineous marriages like Turkey.