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Biomedical subjects

C Altay

Publications and source records attributed to C Altay.

At least 55 records · Page 3Linked to original sources
PubMed1993

Hb Adana or alpha 2(59)(E8)Gly-->Asp beta 2, a severely unstable alpha 1-globin variant, observed in combination with the -(alpha)20.5 Kb alpha-thal-1 deletion in two Turkish patients.

We have identified a severely unstable hemoglobin variant through sequencing of amplified DNA involving the alpha 1-globin gene; the mutation is located in codon 59 (CCG CAG) and results in a Gly-->Asp replacement. This amino acid substitution concerns a glycine residue at an internal position in the E helix, which is in close contact with a glycine residue of the B helix; introduction of the larger and charged aspartic acid residue greatly affects the stability of the molecule. This variant was present in association with a common alpha-thalassemia-1 deletion [-(alpha)20.5 kb] in two adults and caused a severe type of Hb H disease with anemia, low levels of Hb A2, increased zeta chain, and Hb Bart's. In vitro chain synthesis in reticulocytes showed a high specific activity of the variant alpha chain. Only a minute quantity of Hb H was present but instead about 10% of Hb Bart's was observed. The increased synthesis of gamma chains was likely due to specific characteristics of a chromosome with haplotype #3, which was present in both patients. The same family was studied 18 years ago; the improved methodology presently available has led to a corrected diagnosis for these patients.

Adult↗
PubMed1993

Ghosal haemato-diaphyseal dysplasia: a new disorder.

We describe two siblings, products of a first cousin marriage, with diaphyseal dysplasia, severe anaemia, leukopenia, and thrombocytopenia. Radiologically, both had wide medullary cavities with discrete cortical hyperosthosis. Bone marrow was hypocellular. These, and six similar cases in the literature [6], suggest that they represent a form of diaphyseal dysplasia differing from Camurati-Engelmann disease by their radiological appearance, associated haematological abnormalities and autosomal recessive inheritance.

Anemia↗
PubMed1993

Gallbladder pathology in pediatric beta-thalassemic patients. A prospective ultrasonographic study.

Eighty-three beta-thalassemic patients, aged 1.5-19 years, were prospectively studied for evidence of gallbladder pathology by real-time, high-resolution ultrasound. Cholelithiasis was present in 7 patients (8.4%). Sludge, a clinical entity that, when it persists, can be a predisposing factor for cholelithiasis and cholecystitis, was detected in 29 patients (34.9%). Prevalence of sludge to this extent has not been reported in the literature and we believe this is due to better technology offered by modern ultrasound equipment. Pseudo-sludge, a condition that is created by a beam averaging effect (partial-volume phenomenon), at the diverging portion of the ultrasound beam, has always been confusing and a source of difficulties in the ultrasound examination of the gallbladder. For the first time, a method is described, to easily differentiate between true sludge and pseudo-sludge.

Adolescent↗
PubMed1992

Sequence variations in the 5' hypersensitive site-2 of the locus control region of beta S chromosomes are associated with different levels of fetal globin in hemoglobin S homozygotes.

We have compared the sequence of the 5' hypersensitive site-2 (5'-HS-2) of the locus control region (LCR) from a sickle cell anemia (SS) patient homozygous for haplotype 19 and with low levels of fetal hemoglobin (HbF), with the same sequence from an SS patient homozygous for haplotype 3 and with high levels of HbF. Several nucleotide variations were present in the 5'HS-2 of the haplotype 19 individual. One is the A----G at position -10905 that creates an Sp1 binding site GCCCC (A----G)CCCC. A second is the T----G at position -10924 in a sequence that binds both erythroid and ubiquitous factors and exhibits high homology to the long terminal repeat of the Moloney leukemia viruses and Friend murine leukemia virus. Other differences were in the two AT-rich stretches of DNA, and an A----T substitution at position -10390. Dot-blot analyses of amplified DNA from several SS patients showed that these variations are specific for beta S chromosomes with haplotype 19. We also examined the 5'HS-2 sequence from an SS patient who is homozygous for haplotype 19, but has abnormally high levels of HbF (greater than 20%). We observed a cross-over that has placed sequences similar to the 5'HS-2 of haplotype 3 in juxtaposition to the 5' flanking regions of haplotype 19. Thus, a beta S chromosome with haplotype 19 but having a 5'HS-2 (LCR) characteristic for haplotype 3 is associated with high gamma-chain expression. We postulate that factors produced under conditions of hematopoietic stress, together with genetic determinants on the haplotype 3-like LCR sequences, allow for high level expression of gamma-globin genes.

Base Sequence↗
PubMed1992

Beta S haplotypes in various world populations.

We have determined the beta S haplotypes in 709 patients with sickle cell anemia, 30 with SC disease, 91 with S-beta-thalassemia, and in 322 Hb S heterozygotes from different countries. The methodology concerned the detection of mutations in the promoter sequences of the G gamma- and A gamma-globin genes through dot blot analysis of amplified DNA with 32P-labeled probes, and an analysis of isolated Hb F by reversed phase high performance liquid chromatography to detect the presence of the A gamma T chain [A gamma 75(E19)Ile----Thr] that is characteristic for haplotype 17 (Cameroon). The results support previously published data obtained with conventional methodology that indicates that the beta S gene arose separately in different locations. The present methodology has the advantage of being relatively inexpensive and fast, allowing the collection of a vast body of data in a short period of time. It also offers the opportunity of identifying unusual beta S haplotypes that may be associated with a milder expression of the disease. The numerous blood samples obtained from many SS patients living in different countries made it possible to compare their hematological data. Such information is included (as average values) for 395 SS patients with haplotype 19/19, for 2 with haplotype 17/17, for 50 with haplotype 20/20, for 2 with haplotype 3/3, and for 37 with haplotype 31/31. Some information on haplotype characteristics of normal beta A chromosomes is also presented.

Africa↗
PubMed1992

Homozygosity for dominant form of hereditary spherocytosis.

A 6-month-old male infant with hereditary spherocytosis (HS) who was the first child of a cousin marriage is presented. The patient had splenomegaly and severe anaemia. Examination of the peripheral blood smear revealed spherocytes and the osmotic fragility of red blood cells was greatly increased. Physical examination of the parents revealed that both parents had mild anaemia, jaundice and splenomegaly. Their peripheral blood smears showed spherocytes and a few acanthocytes. Osmotic fragility of red blood cells of both parents were increased. Red cell membrane electrophoresis indicated a deficiency of ankyrin in the propositus; mild deficiency was also detected in both parents. Electrophoretic patterns of red cell membrane proteins suggested that the child was homozygous for the dominant form of HS associated with ankyrin deficiency, while both parents had the simple dominant form of the disease. Red blood cell transfusions were given to the patient starting at the age of 1 month until splenectomy was performed at the age of 1 year that resulted in complete haematological response. This observation indicates that homozygosity for dominant type of HS associated with ankyrin deficiency is life compatible and splenectomy may cure the anaemia.

Ankyrins↗
PubMed1992

Hb H disease caused by a homozygosity for the AATAAA-->AATAAG mutation in the polyadenylation site of the alpha 2-globin gene: hematological observations.

We have identified 7 patients with Hb H disease as homozygotes for a mutation in the polyadenylation site (AATAAA-->AATAAG) and have compared their hematological data with those of Hb H patients having other types of alpha-thalassemia determinants. All 7 patients exhibited moderate anemia with microcytosis and hypochromia being similar to that observed in the other patients. Relatives with a heterozygosity for this mutation are borderline microcytic and hypochromic without a significant anemia but with a low in vitro alpha/beta chain synthesis ratio. Analyses of the hemoglobin components identified low levels of Hb A2 and Hb H that were comparable to those found in other patients with Hb H disease; the level of the zeta-chain was low (average 0.14%).

Adolescent↗
PubMed1992

Pearson's marrow-pancreas syndrome in 2 Turkish children.

Two unrelated infants, 1 female and 1 male, with Pearson's syndrome are presented. Both patients presented with severe macrocytic refractory anemia starting early in infancy. Investigation of the mitochondrial (mt), DNA showed that one of the patients had a 4,977 bp deletion, and the other had a 4.5 kb mtDNA deletion. It is concluded that Pearson's syndrome should be borne in mind in the differential diagnosis of refractory anemia especially when there are accompanying gastrointestinal disturbances and metabolic acidosis.

Anemia, Refractory↗
PubMed1991

Quantities of adult, fetal and embryonic globin chains in the blood of eighteen- to twenty-week-old human fetuses.

The prenatal diagnostic program, established at Hacettepe University in Ankara for the purpose of detecting beta-thalassemia (beta-thal), sickle cell anemia (SS), and Hb S-beta-thal, offered the opportunity of evaluating the relative quantities of adult (beta A, beta S), fetal (G gamma, A gamma, A gamma T), and embryonic (epsilon, zeta) chains in 26 fetuses, aged 18-20 weeks. Methodology involved micro high-performance liquid chromatographic (HPLC) procedures and immunology using an mAb, specific for the embryonic epsilon chain. A good correlation was observed between the beta/gamma in vitro chain synthesis ratio and the level of beta A and/or beta S chains determined by reversed-phase HPLC; the combination of these two sets of data strengthens the prenatal diagnostic approach of detecting beta-thal major but not beta-thal trait. The levels of the different gamma chains were about as observed in newborn babies; the frequency of the A gamma T variant in the 26 fetuses was the same as observed for a larger group of Turkish newborn babies. The level of the embryonic zeta chain was higher than seen in full-term babies and varied between 0 and 1.3%; 5 of the 26 fetuses showed the complete absence of zeta. The embryonic epsilon chain was not detectable, not even in babies with beta-thal major. These data indicate that the synthesis of epsilon is completely turned off in fetuses at the age of 18-20 weeks, while that of zeta continues, albeit at a low level.

Adult↗
PubMed1991

The G----A mutation at position +22 3' to the Cap site of the beta-globin gene as a possible cause for a beta-thalassemia.

We describe the occurrence of a chromosome with a G----A mutation at position +22 relative to the Cap site that was found in five patients with beta-thalassemia. All patients had a common type of beta-thalassemia mutation on the second chromosome, namely the frameshift at codon 8 (-AA), the IVS-I-110 (G----A) and the IVS-II-1 (G----A) mutations. The beta genes of two patients, including the 5' and 3' untranslated regions, were completely sequenced and no other mutations, except a few polymorphic sites, were observed. Dot-blot analyses failed to demonstrate this G----A mutation at +22 in nearly 400 beta-thalassemia chromosomes and 180 normal chromosomes. Heterozygotes have the features of a high Hb A2-beta-thalassemia heterozygosity, although the hematological parameters might be less abnormal than observed in heterozygotes for the more common beta-thalassemia mutations. The possibility has been presented suggesting that this mutation might impair the binding of mRNA to ribosomes. Another mutation in this segment of DNA, i.e. a C----G mutation at position +20, is observed exclusively on a chromosome which also carries the C----G mutation at IVS-II-745. It is postulated that the +20 C----G mutation accentuates the beta-thalassemia condition caused by the IVS-II-745 mutation; the mechanism might be similar to that suggested for the G----A at +22 mutation.

Alleles↗
PubMed1990

Variation in the level of fetal hemoglobin in (delta beta) (0)-thalassemia heterozygotes with different numbers of alpha-globin genes.

The Sicilian type of (delta beta) (0)-thalassemia characterized by a approximately 13 kb deletion, was present in a Turkish boy who is a homozygote and in his heterozygous parents who are first cousins. The father with approximately 21% Hb F had five alpha-globin genes (alpha alpha/alpha alpha alpha) and the mother with approximately 10% Hb F had an alpha-thal-2 heterozygosity (alpha alpha/-alpha). The difference in Hb F level is explained by a decreased formation of alpha 2 gamma 2 tetramers in the mother with an alpha-chain deficiency while the extra alpha-globin gene in the father will promote Hb F production.

Child, Preschool↗
PubMed1990

Beta-thalassemia intermedia in Turkey.

DNA data have been collected for 41 patients with beta-thalassemia intermedia without transfusion dependency. They belonged to 33 families, and 45 of their parents were included in the study. Eight patients were homozygous for the frameshift at codon 8 (-AA), and nine were homozygous for the IVS-2 nt 1 (G----A) mutation; haplotypes IV and III, respectively, were associated with these mutations. Three patients had a G gamma A gamma(delta beta)0-thalassemia homozygosity, characterized by a deletion of 13 kb. Of the remaining subjects, ten had a homozygosity for the IVS-1 nt 6 (T----C) mutation, and five were compound heterozygotes for one mild and one severe thalassemia determinant. Combinations with Hb Knossos, the T----A mutation at nt -30, the C----T mutation at nt -101, the G----A and G----C mutations at IVS-1 nt 5, and the G----A mutation at IVS-1 nt 110 were the other thalassemia determinants resulting in beta-thalassemia intermedia in the six remaining patients. Haplotypes IV and IX were associated with the latter three mutations. The C----T mutation at nt -158 5' to the G gamma gene was characteristic for haplotypes III, IV, and IX. Genotype and phenotype correlation indicated significant differences in some of the hematological parameters among patients with the frameshift at codon 8 (-AA) or with the IVS-2 nt 1 (G----A) mutation, with both the frameshift at codon 8 and the T----C mutation at IVS-1 nt 6, and with both the IVS-2 nt 1 (G----A) and IVS-1 nt 6 (T----C) mutations. Statistically significant differences were found in the mean values for hemoglobin (Hb) A2 in heterozygotes with the frameshift at codon 8 (-AA) and the IVS-1 nt 5 (G----A) mutation. Variations in the number of alpha-globin genes resulted in modifications of the phenotypical expression of the beta-thalassemia intermedia determinants.

Chromosome Deletion↗
PubMed1990

Beta-thalassemia in Turkey.

A review is presented of the various beta-thalassemia alleles observed in nearly 191 patients with beta-thalassemia major and their 182 heterozygous relatives. Determination was by gene amplification and dot-blot hybridization with synthetic probes, specific for 27 different mutations. Eighteen mutations have been observed; six of these account for nearly 83% of all thalassemia abnormalities. A new mutation, i.e. a G----C mutation at the acceptor splice site of IVS-I, was found in one teenager who was homozygous for this disease. The high consanguinity among the families was considered the main reason for the high number of patients with a homozygosity for the IVS-I-110 (G----A) mutation. Combinations of different mutations were present in many patients; some were mildly affected because of the specific mutation present on one chromosome. Combinations of classical beta-thalassemia and an abnormal hemoglobin mainly concerned Hb S. Hbs Knossos and Lepore were rare occurrences. A comparison of hematological data for adults with heterozygosities for some of the common alleles confirmed the low Hb A2 values in IVS-I-6 (T----C) heterozygotes and the high Hb F values for codon 8 (-AA), IVS-II-1 (G----A), and IVS-I-1 (G----A) heterozygotes.

Adolescent↗
PubMed1989

A C----T substitution at nt--101 in a conserved DNA sequence of the promotor region of the beta-globin gene is associated with "silent" beta-thalassemia.

Sequence analyses and dot-blot analyses with synthetic oligonucleotide probes have identified eight individuals in three Turkish families and one Bulgarian family with one chromosome having a C----T mutation at nucleotide position--101 relative to the Cap site of the beta-globin gene. This nucleotide is part of one of the conserved blocks of nucleotides within the promoter region; in vitro expression analyses with the chloramphenicol acetyltransferase system showed that this substitution will decrease the effectiveness of transcription. Five subjects had a thalassemia intermedia due to the additional presence of a known classical high hemoglobin (Hb) A2 beta-thalassemia mutation on the second chromosome; their hematologic condition was relatively mild. The three persons with a heterozygosity for the--101 C----T mutation had normal hematologic data without microcytosis but with high-normal levels of Hb A2 and a mild imbalance in chain synthesis. The newly discovered mutation is considered one of the silent types of beta-thalassemia. It is relatively rare because it was absent among several hundred normal and beta-thalassemia chromosomes.

Base Sequence↗
PubMed1989

The levels of zeta, gamma, and delta chains in patients with Hb H disease.

Details are given of a study of blood samples from 24 patients with Hb H disease from different Mediterranean countries and from the Far East. Four different types of alpha-thal-1 (--) were observed, namely -(alpha) (approximately 20.5-kb deletion); --MED-I (approximately 17.5-kb deletion); --MED-II (greater than 26.5-kb deletion); and --SEA (approximately 18-kb deletion, in Orientals only). The alpha-thal-2 was mainly of the deletion type (16 with the 3.7-kb deletion; 1 with the 4.2-kb deletion), while 4 of the 7 patients with a nondeletional type had the five-nucleotide deletion at the donor splice site of the first intron of the alpha 2 gene. All patients had a mild-to-moderate hemolytic anemia; no significant differences in hematology were observed between the groups. Hb A2 was decreased to about one-third of the normal level. The Hb H formation varied considerably and its quantitation was not always satisfactory. Patients with Hb H disease due to any alpha-thal-1 combined with a nondeletional alpha-thal-2 had the highest Hb H levels and a more marked anemia. The zeta chain production was small and absent in patients with the MED-II type of alpha-thal-1 because this deletion included the zeta and psi zeta genes. The highest zeta chain levels were present in the four patients with the SEA type of alpha-thal-1. The gamma chain production was increased, particularly in patients with a mutation of C----T at position -158 to the G gamma globin gene. This gamma chain was primarily present as Hb Bart's (or gamma 4) and only about 15% was recovered as Hb F or alpha 2 gamma 2. The evaluation of the rate of gamma chains produced in these patients was greatly facilitated by data from one patient who had Hb H disease and a heterozygosity for the A gamma-beta+-HPFH. The low levels of Hb A2 and of Hb F (relative to Hb Bart's) can be explained by a decreased affinity of alpha chains for delta and gamma chains as compared with beta chains in conditions of severe alpha chain deficiency.

Adolescent↗
PubMed1989

Role of protein C in childhood cerebrovascular occlusive accidents.

A group of 23 children with cerebrovascular occlusion of unknown etiology were re-evaluated 6 months-2 years later. Plasma protein C levels were determined with the coagulation method and were low in 10 cases. The role of this deficiency and the necessity of this test in cerebrovascular occlusion is discussed.

Adolescent↗
PubMed1989

Molecular heterogeneity of beta-thalassemia intermedia in Turkey.

A total of 38 patients with beta-thalassemia intermedia from 30 families were were studied. Twelve of the thirty unrelated patients had beta zero-thalassemia which was due to a homozygosity for one of two different thalassemia defects, namely the frameshift at codon 8, and the IVS-II-1 G----A mutation. Another mild variation, a beta +-thalassemia, was a homozygosity for the mutation of T----C at position 6 of IVS-1 (10 patients). Compound heterozygosities for mild thalassemic determinants or for one mild and one severe beta-thalassemic determinant were also found in some patients with beta-thalassemia intermedia. The mutations at beta-39 and IVS-I-110 were the most commonly occurring thalassemic determinants in these patients. Correlations between genotype and phenotype indicated significant differences in some of the hematological parameters among patients with the IVS-I-6 and the frameshift at codon 8, IVS-I-6 and IVS-II-1, and the frameshift at codon 8 and IVS-II-1 mutations.

Adolescent↗