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.

Carbonic anhydrase VA deficiency: a very rare case of hyperammonemic encephalopathy

Objectives Carbonic anhydrase VA (CAVA) deficiency is a rare autosomal recessive inborn error of metabolism that leads to acute metabolic crises, especially in the neonatal or infantile period. It is caused by a deficiency of the enzyme CAVA, which is encoded by the CA5A gene. Case presentation Fifteen patients with homozygous pathogenic CA5A mutations involving 10 different lesions have been reported in the literature up to date. Main clinical and biochemical features of CAVA deficiency include lethargy, hyperammonemic encephalopathy, metabolic acidosis, elevated lactate and hypoglycemia. In most patients reported so far, a single metabolic decompensation attack has been reported, and they have remained stable thereafter with no further crisis. Conclusions We report the 16th case of CAVA deficiency, who was diagnosed by whole-exome sequencing and showed a typical course of the disease with normal development at 18 months.

A novel homozygous nonsense mutation (p.Y78*) in TMPRSS6 gene causing iron-refractory iron deficiency anemia (IRIDA) in two siblings

Iron-refractory iron deficiency anemia (IRIDA) is an inherited iron metabolism disorder caused by mutations in TMPRSS6 gene encoding matriptase-2, which results in increased hepcidin synthesis. The hallmarks of the disease are hypochromic microcytic anemia, low transferrin saturation, slightly low or normal ferritin levels in contrast to classic iron deficiency anemia (IDA), inadequate response to oral iron, and only a partial response to parenteral iron. We report here a 6-year-old Syrian boy with unexplained microcytic anemia since one year of age. Genetic analysis of the TMPRSS6 gene revealed a novel homozygous nonsense mutation in exon 3 (c.234C > G; p.Y78* or p.Tyr78*). In the presence of hypochromic microcytic anemia accompanied by atypical iron parameters not in accordance with classic IDA, and inadequate response to iron therapy, IRIDA should be remembered in the differential diagnosis.

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.

Inherited coagulation disorders in Turkish children: A retrospective, single-center cohort study

OBJECTIVE

This study aims to investigate the distribution, clinical characteristics and outcome of inherited coagulation disorders (ICD) in Turkish children.

SUBJECTS AND METHODS

Data from all children (age<18 years) with ICD examined in our center were retrospectively reviewed.

RESULTS

There were 403 children with ICD (233 males and 170 females) with a median age of four years at diagnosis. The percentages of von Willebrand disease (vWd), hemophilia and rare bleeding disorders (RBD) were 40 %, 34 % and 26 %, type-1, type-2 and type-3 vWd were 63 % 17 % and 20 %, hemophilia A and B were 84 % and 16 %, and severe, moderate and mild hemophilia were 48 %, 30 % and 22 %, respectively. Factor VII and FXI deficiencies were the most prevalent, comprising 56 % and 22 % of all children with RBD, respectively. Parental consanguinity rates were 72 % in type-3 vWd and 61 % in severe RBD. The overall prevalence of gastrointestinal bleedings was 4.5 % (18/403), intracranial bleeding (ICB) was 4.96 % (20/403), mortality from ICB was 30 % (6/20) and the overall mortality rate was 1.49 % (6/403). No life-threatening bleeding was seen during regular prophylaxis. Chronic arthropathy prevalence in severe hemophilia was 8 % with primary prophylaxis and 53 % with demand therap. Inhibitor prevalence was 14 % in hemophilia-A and 5 % in hemophilia-B.

CONCLUSIONS

These data show that vWd is the most common ICD, type-3 vWd and RBD are prevalent due to frequent consanguineous marriages and diagnosis of ICD is substantially delayed in Turkish children. Prophylactic replacement therapy prevents occurrence of life-threatening bleedings and reduces the development of hemophilic arthropathy.

Iron-refractory iron deficiency anemia (IRIDA) cases with 2 novel TMPRSS6 mutations

Iron-refractory iron deficiency anemia (IRIDA) is a rarely diagnosed autosomal recessive disorder that presents with hypochromic, microcytic anemia due to mutations in TMPRSS6, which encodes matriptase-2. Contrary to classical iron deficiency anemia, serum hepcidin levels are found to be elevated in this disorder. Here, we report 5 cases from 4 unrelated families with inadequate response to iron therapy, who were consequently diagnosed as IRIDA. The mean age of the cases at diagnosis was 5.0 years (range: 0.7-11.3 years). All cases were either homozygous or compound heterozygous for missense or frameshift mutations in the TMPRSS6 gene, 2 of the mutations being novel (Cys410Ser and Leu689Pro). IRIDA should be considered in patients with findings of iron deficiency anemia unresponsive to oral iron therapy, whose serum ferritin levels are found normal or elevated.

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.

Severe vitamin B₁₂ deficiency in a 15-year-old boy: presentation with haemolysis and pancytopenia

A 15-year-old boy on a vegetarian diet presented with severe macrocytic anaemia (haemoglobin, 5.1 g/dL; mean corpuscular volume, 116 fL) in addition to leucopenia and thrombocytopaenia (pancytopenia), icterus secondary to haemolysis and splenomegaly. Laboratory investigations revealed severe vitamin B12 (cobalamin) deficiency. Following cobalamin replacement therapy, the patient reported increased well-being, including appetite and weight gain, and his icterus resolved. In the follow-up laboratory examinations, leucocyte and platelet counts in addition to serum bilirubin and lactate dehydrogenase levels normalised. At the end of 2 months, laboratory findings, including haemoglobin level, were all within the normal range. We present this case as a reminder that severe vitamin B12 deficiency may present with findings mimicking acute leukaemia (pancytopenia and splenomegaly) and findings suggestive of pseudothrombotic microangiopathy.

ALL-BFM 95 treatment in Turkish children with acute lymphoblastic leukemia--experience of a single center

Little is known about the likelihood of curing children with high-dose chemotherapy regimens for treatment of childhood acute lymphoblastic leukemia (ALL) in Turkey. The authors here report their 13 years' experience with original ALL-BFM (Berlin-Franfurt-Münster) 95 protocol in a cohort of 140 Turkish children with ALL. Complete remission rate was 97.7% with a relapse rate of 12.9% and death rate 17.9% during a median follow-up of 69 months. The event-free survival (EFS), disease-free survival (DFS), and overall survival (OS) in these patients at 12 years were 75.0%, 87.1%, and 80.6%, respectively. These results show that ALL-BFM 95 protocol is equally applicable in the experienced centers, even in developing countries without substantial treatment-related toxicity. High rate of infection deaths are to be reduced with correct policies.