Ebru Yilmaz Keskin

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.

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.

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

ABSTRACT 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.

Evaluation of Pediatric Bleeding Questionnaire in Turkish Children With Von Willebrand Disease and Platelet Function Disorders

The diagnosis of mild bleeding disorders is not easy as most of the “healthy” individuals also report bleeding symptoms. In order to get a precise bleeding history, Pediatric Bleeding Questionnaire (PBQ) has been developed. In our study, Turkish children diagnosed with Von Willebrand disease (VWD), platelet function defect (PFD), and healthy children without any symptoms (control group 1) and healthy children with symptoms but found hemostatically normal (control group 2) were analyzed with PBQ. The cut off level for “positive bleeding score” was found to be ≥2 (area under the curve [AUC]: 0.785, 95% confidence interval [CI]: 0.718-0.852). The sensitivity, specificity, positive predictive value, and negative predictive value of PBQ to define VWD versus control group 1 was 100%, 97.4%, 96.4%, and 100%; VWD versus control group 2 was 100%, 53.1%, 64.3%, and 100%; PFD versus control group 1 was 93.3%, 53.1%, 73.7%, and 85%; and PFD versus control group 2 was 93.3%, 53.1%, 73.7%, and 85%, respectively.

First report of an SH2D1A mutation associated with X-linked lymphoproliferative disease in Turkey

X-linked lymphoproliferative disease (XLP) is a rare disorder characterized by an extreme vulnerability to EpsteinBarr virus (EBV) infection, frequently resulting in hemophagocytic lymphohistiocytosis (HLH) [1]. XLP-1, its more common subtype, is caused by defects in the SH2D1A gene that encodes the signaling lymphocyte activation molecule-associated protein (SAP), which regulates the activation of T lymphocytes [2], whereas XLP-2 is caused by mutations in the XIAP gene, also known as BIRC4 [3].

First Observation of Hemoglobin San Diego, a High Oxygen Affinity Hemoglobin Variant, in Turkey

Figure 1. A) Pedigree of the family with erythrocytosis and hemoglobin (Hb) San Diego, illustrating dominant mode of inheritance of erythrocytosis. The propositus is indicated with an arrow; B) high-performance liquid chromatography (premier Hb9210 resolution) showing the presence of Hb San Diego. Ebru Yılmaz Keskin1, Ali Fettah2, Ana Catarina Oliveira3, Şule Toprak2, Andreia Lopes3, Celeste Bento3,4

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.

Parathyroid adenoma and chondrosarcoma after treatment of pediatric Hodgkin disease.

Treatment of Hodgkin disease (HD) with chemoradiotherapy in children is associated with increased risk for developing secondary neoplasms. Parathyroid adenoma (PTA) and chondrosarcoma (CS) are quite rare types of secondary neoplasms after HD. We describe a 5-year-old boy with stage IV HD, successfully treated with MOPP (mechlorethamine, vincristine, procarbazine, and prednisone)/ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) chemotherapy followed by 35 Gy mantle radiotherapy who developed primary hyperparathyroidism because of benign PTA at the age of 20 years, and died of CS in thoracic vertebrae at the age of 22 years. Consecutive occurrence of PTA and CS after treatment of pediatric HD, to the best of our knowledge, has not been reported earlier.