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Biomedical subjects

C Oner

Publications and source records attributed to C Oner.

52 records · Page 3Linked to original sources
PubMed1990

Hb Icaria-Hb H disease: identification of the Hb Icaria mutation through analysis of amplified DNA.

Hb Icaria-Hb H disease was observed in a Yugoslavian teenager who exhibited moderate anaemia with severe microcytosis and hypochromia and 16% Hb H. Four of his relatives were Hb Icaria heterozygotes; their haematological data were comparable to those with a deletional type of alpha-thalassaemia-2. The patient also had an additional alpha-thalassaemia-1 deletion, an approximately 20.5 kb deletion, common among Mediterranean populations. The Hb Icaria mutation, i.e. the TAA----AAA mutation at codon 142, was identified by hybridization of amplified DNA with specific probes. The mutation is located on the alpha 2-globin gene; the one remaining alpha 1-globin gene is apparently able to compensate sufficiently for the loss of the three alpha-globin genes to maintain a haemoglobin level of 8-9 g/dl.

Adolescent↗
PubMedDate not supplied

Chronic hemolytic anemia associated with glucose 6-phosphate dehydrogenase (Guadalajara)1 159 C --> T (387 Arg --> Cys) deficiency associated with Gilbert syndrome in a Turkish patient.

The case of an 8-year-old male child with severe kernicterus sequelae is presented in this paper. The child's hemoglobin value varied between 6.0 and 10.8 g/dL and his reticulocyte count ranged between 3.4 and 46.0% during the steady-state condition and hyperhemolytic crisis, respectively. A chronic hemolytic type of red cell G6PD deficiency was diagnosed. DNA studies indicate that the mutation was G6PD Guadalajara 1159 C --> T (387 Arg --> Cys) that is situated at the NADP binding site. Additionally, extra nucleotides of (TA) in the A(TA)n TAA motif of the promoter region of the uridine diphosphate-glucuronosyltransferase gene (UGT-1 A) were found to be homozygous in the patient. The coexistence of Gilbert syndrome with a chronic type of G6PD deficiency was suggested as a cause of neonatal hyperbilirubinemia leading to kernicterus.

Anemia, Hemolytic↗
PubMedDate not supplied

Effect of alpha-gene numbers on the expression of beta-thalassemia intermedia, beta-thalassemia and (delta beta)0-thalassemia traits.

The effects of variations in alpha-gene numbers on phenotypical expression of beta-thalassemia are assessed in 11 subjects of 8 families. The study indicates that coexistence of alpha-thalassemia (-alpha3.7/alpha alpha) decreases the HbF in IVSI-6 homozygote and in delta beta thalassemia trait and may ameliorate the disease in beta-thalassemia compound heterozygotes associated with one mild and one severe beta-thalassemia mutation. Coexistence of alpha-gene triplication is associated with an increase in HbF value and may increase the severity of beta-trait or beta-thalassemia intermedia. The effects of alpha-gene triplication on phenotypic expression of beta-thalassemia trait may not be uniformly observed in every subject affected with a similar genotype.

Adolescent↗
PubMedDate not supplied

Genotype-phenotype analysis in HbS-beta-thalassemia.

Genotypes and phenotypes were studied in 31 Turkish HbS-beta-thalassemia patients. In 19 patients the beta-thalassemia mutations were beta+ and in 12 the beta 0 phenotype. The IVSI-110 mutation was found in 45% of the patients. IVSI-1, beta 39, IVSII-1 and FSC8 are the genotypes associated with beta 0-thalassemia. Hematological data were evaluated at the time of diagnosis and 4 years after diagnosis. The mean HbF value was 13 +/- 7.8% at diagnosis and 9.7 +/- 7.8% 4 years later. A significant negative correlation was observed between the age of the patients and the HbF value (p < 0.05). No statistically significant differences were observed between the mean of hematological parameters in beta(+)- and beta 0-thalassemia patients except for the mean HbF value which were 10.7 +/- 6.9 and 15.9 +/- 7.7% in beta(+)- and beta 0-thalassemia, respectively (p < 0.05). The study indicated that beta-thalassemia mutations in trans to the HbS mutation do not exert any beneficial effect on the manifestation of the disease.

Adolescent↗
PubMedDate not supplied

Hb Hakkari or alpha 2 beta 2 31(B13)Leu-->Arg, a severely unstable hemoglobin variant associated with numerous intra-erythroblastic inclusions and erythroid hyperplasia of the bone marrow.

A severely unstable hemoglobin variant, Hb Hakkari or alpha 2 beta 2 31 (B13)Leu-->Arg, has been observed in a 5-year-old Turkish girl with a severe hemolytic anemia without Heinz body formation. A modest increase in liver and spleen size was present and the level of Hb F was a high 33%. The variant could not be observed in red cells and was only detected through sequencing of the amplified beta-globin gene and also by hybridization with specific oligonucleotide probes. The parents were normal, and it is assumed that the variant occurred as a de novo mutation. Smears from bone marrow aspirates showed numerous inclusion bodies in the erythroblast and, as a result, a erythroid hyperplasia. It is suggested that the hemoglobin variant which is unstable and is readily losing its heme group because one of the heme binding sites has been lost, precipitates in the erythroblasts, thus interfering with the maturation process and causing the severe anemia.

Anemia, Hemolytic, Congenital↗
PubMedDate not supplied

Prenatal diagnosis of hemoglobinopathies in Turkey: Hacettepe experience.

Prenatal diagnosis of hemoglobinopathies was performed in 250 fetuses at risk for hemoglobinopathies. The main diagnostic procedures were in vitro hemoglobin synthesis analysis in fetal blood and analysis of DNA obtained from chorionic villus samples. Sixty-six percent of the fetuses were at risk for beta thalassemia major and 28% for sickle cell anemia. Beta thalassemia mutations were heterogenous, and 51 fetuses examined by the DNA technique were found to be at risk for at least 20 different combinations.

Anemia, Sickle Cell↗
PubMedDate not supplied

Vitamin d-receptor gene polymorphisms and vertebral bone density in men with idiopathic hypogonadotrophic hypogonadism.

BACKGROUND: Optimal peak bone mass is closely related to sufficient and appropriately timed androgen release. However, attainment of peak bone mass in men, as in women, is under genetic control, as well as being subject to hormonal and mutational effects. With increasing recognition of osteoporosis and related fractures in men, it is of interest to consider whether there is relationship between bone density and vitamin D receptor (VDR) polymorphisms, as described in women. MATERIAL AND METHODS: To assess the influence of allelic variation in the VDR gene on vertebral bone density in men with idiopathic hypogonadrotrophic hypogonadism (IHH), 27 patients (mean age 21.4 +/- 0.4 yrs) and 25 age-and-BMI matched healthy males (mean age 21.2 +/- 0.3) were genotyped using three restriction enzymes (Apa I, Bsm I, and Taq I). Vertebral bone mineral density was measured using dual energy X-ray absorptiometry (DEXA). RESULTS: As expected, vertebral bone density was reduced significantly in patients with IHH (p < 0.001). Despite weak evidence for an association between Apa I polymorphism and vertebral bone density in the IHH group (r = 0.454, p = 0.017 and r2 = 0.20), VDR genotype was not associated with vertebral bone density in either group. When analyzing homozygous haplotypes, the probability of carrying the favorable BAt haplotype was greater in the control group (OR = 2.000 vs. 0.500). CONCLUSION: We conclude that VDR genotype has no influence on vertebral bone density in men with IHH. Thus, allelic variation in the VDR cannot help define those at increased risk for osteoporosis and related fractures among such patients.

Absorptiometry, Photon↗
PubMedDate not supplied

Compound heterozygosity for hemoglobin Knossos [alpha 2 beta 2 27 (B9) Ala-Ser] and IVS I-1 mutation.

A three-year-old female with compound heterozygosity for Hb Knossos and IVS-I-1 mutation is presented. On physical examination she had no abnormality except for pallor. Hb was 6.9 g/dl, MCV 61 fl, Hb A2 2% and Hb F 38.5%. Acrylamidegel electrophoresis at a pH of 6 revealed the presence of Hb Knossos in the child and her father. DNA studies revealed that the child was compound heterozygous for Hb Knossos and the IVS I-1 mutation. When the clinical expression of this combination in a previously reported patient with Hb Knossos/FSC8 mutation is compared, it is shown that the newly presented patient has a more severe condition, indicating that the mutations in the trans of Hb Knossos may play a role in the phenotypical expression of the disease.

Anemia↗