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E Kanavakis

Publications and source records attributed to E Kanavakis.

At least 19 recordsLinked to original sources
PubMed2007

p53 codon 72 Pro homozygosity increases the risk of cutaneous melanoma in individuals with dark skin complexion and among noncarriers of melanocortin 1 receptor red hair variants.

BACKGROUND: p53 has a common polymorphism at amino acid 72, encoding either arginine or proline. p53Arg and p53Pro exhibit differences in various biological activities, such as cell-cycle arrest and induction of apoptosis. Numerous epidemiological studies have examined the role of this polymorphism in several human malignancies, including cutaneous cancers, with contradictory results. OBJECTIVES: To investigate the germline frequency of p53 codon 72 polymorphism in malignant melanoma in a Mediterranean population, and to examine possible associations with various clinicopathological factors. METHODS: In this hospital-based case-control study we used allele-specific polymerase chain reaction for p53 codon 72 genotyping in blood specimens from 107 Greek patients with sporadic cutaneous melanoma and 145 healthy controls. RESULTS: After adjustment for age, sex and phototype the Pro/Pro genotype was associated with increased risk for cutaneous melanoma compared with the Arg/Arg genotype (adjusted odds ratio, OR 3.17, 95% confidence interval, CI 1.03-9.78). This correlation was more pronounced in subjects with phototypes III or IV (adjusted OR 9.56, 95% CI 1.56-58.46), dark skin (adjusted OR 10.96, 95% CI 1.64-73.28), dark eyes (adjusted OR 8.86, 95% CI 1.69-46.52) and dark hair (adjusted OR 3.17, 95% CI 1.01-9.95), and among noncarriers of melanocortin 1 receptor gene (MC1R) red hair polymorphisms (adjusted OR 2.99, 95% CI 1.02-8.78). CONCLUSIONS: p53 codon 72 Pro/Pro genotype could be a risk factor for the development of melanoma in the Greek population, especially in subgroups with darker skin pigmentation, as well as among noncarriers of the MC1R red hair polymorphic variants.

Adult↗
PubMed2006

Clinical manifestations in 17 Greek patients with Goldenhar syndrome.

Goldenhar (GS) syndrome is a well-recognised developmental disorder involving first and second branchial arches and characterized by considerable phenotypic variability. The present study presents clinical data on the morphologic features, hearing, ophthalmologic, orthopaedic, neurological, cardiovascular, genitourinary and gastrointestinal evaluation of 17 Greek patients (one pair of monozygotic twins) aged 20 days to 23 years with the clinical diagnosis of GS and with a normal karyotype. The most consistent findings were auricular defects (94%), followed by facial (76%) and ocular anomalies (65%), 70% unilateral, mainly right-sided. In the majority of our patients (90%) mandibular hypoplasia was ipsilateral to the dysplastic ear or the most severely affected ear in bilateral cases. Hearing loss, mainly conductive, was noted in 76% of our patients. Skeletal defects were evident in 23%, while cardiovascular, genitourinary and gastrointestinal in 18%, 23% and 12% respectively. The most frequent neurological manifestation was facial nerve paralysis (12%), while the incidence of mental retardation was higher (23%) than reported in the literature, presumably attributed to the severe hearing and vision loss. In a pair of monozygotic twins of our study discordance of clinical findings was noted. Precise evaluation of GS patients and multidisciplinary care management is necessary to avoid possible complications of many systems and to offer appropriate genetic counselling to the family.

Abnormalities, Multiple↗
PubMed2005

Asporin and knee osteoarthritis in patients of Greek origin.

Ostearthritis (OA) is characterized by focal areas of loss of the articular cartilage in synovial joints, associated with varying degrees of osteophyte formation, subchondral bone change and synovitis. The Asporin (ASPN) gene which encodes a protein of the extracellular cartilage matrix contains a triplet repeat encoding for aspartic acid (D) within exon 2 The D14 allele was found associated with knee and hip osteoarthritis in case-control study in the Japanese population. Genotyping Greek knee OA patients for the D repeats we determined that the D15 allele could be considered a risk allele for our population.

Aged↗
PubMed2005

Birth of a healthy infant following trophectoderm biopsy from blastocysts for PGD of beta-thalassaemia major.

PGD is a well accepted reproductive choice for couples at genetic risk and involves the diagnosis and transfer of unaffected IVF embryos. PGD for monogenetic diseases is most commonly accomplished by the biopsy of one or two blastomeres from cleavage stage embryos, followed by PCR-based protocols. However, PCR-based DNA analysis of one or two cells is subject to several problems, including total PCR failure, or failure of one allele to amplify. Trophectoderm biopsy at the blastocyst stage enables the removal of more than two cells for diagnosis while being non-invasive to the inner cell mass which is destined for fetal development. The aim of this study was to develop a safe, reliable technique for the biopsy of trophectoderm cells from human blastocysts. This case report demonstrates that removal of trophectoderm cells prior to blastocyst transfer is compatible with implantation and development to term. Here we report successful PGD for beta-thalassaemia following trophectoderm cell biopsy from blastocysts and the birth of a healthy infant.

Adult↗
PubMed2004

Severe hypertriglyceridaemia in diabetic ketoacidosis: clinical and genetic study.

The lipoprotein lipase coding gene sequence was analysed on a 10-year-old girl with new-onset Type 1 diabetes mellitus (DM), ketoacidosis and severe hypertriglyceridaemia (TG > 112.9 mmol/l), revealing that the patient was a compound heterozygote for two mutations, D9N in exon 2 and S447X in exon 9. Although these two mutations usually do not considerably impair lipolytic enzyme activity, the combination of both in this patient may play a role in the development of severe hypertriglyceridaemia.

Child↗
PubMed2003

Cystic fibrosis in Greece: molecular diagnosis, haplotypes, prenatal diagnosis and carrier identification amongst high-risk individuals.

Cystic fibrosis (CF) mutation analysis on 437 CF patients, characterized 80 different mutations (20 so far specific to our population) accounting for 91% of CF genes and generating 103 different genotypes. Eight mutations were common [F508del (53.4%), 621+1G>T (5.7%), G542X (3.9%), N1303K (2.6%), 2789+5G>A (1.7%), 2183AA>G (1.4%), E822X (1.4%), R1158X (1%)], 12 showed frequencies between 0.5% and 1%, while the remaining (60) were very rare (1 to 3 alleles). Denaturing gradient gel electrophoresis (DGGE) screening of 12 exons (3, 4, 7, 10, 11, 13, 14b, 16, 17b 20 and 21) detected 85.5% of CF alleles. Haplotypes for eight diallelic and three microsatellite markers have been characterized for the common, a few rare and novel Greek mutations. Results of 165 prenatal diagnoses (including 49 due to bowel hyperechogenicity), testing a total of 41 different parental genotypes, are reported. One hundred and sixteen prenatal tests resulted in 22 affected, 59 heterozygous, 34 normal fetuses and one incomplete diagnosis. Of the 49 echogenic bowel fetuses, 3 were heterozygotes. Carrier screening was initiated, with emphasis on individuals and couples in high-risk groups - with a family history of CF, one partner with CF, and couples with male infertility seeking in vitro fertilization (IVF). Mutation analysis on 672 individuals (120 couples, 91 unaffected CF siblings, 283 CF family relatives and 58 general population subjects), identified a total of 176 heterozygotes and 7 couples where both partners were CF heterozygotes. Prenatal diagnosis was performed in 4 cases and 3 were counseled on the availability of a prenatal test.

Alleles↗
PubMed2002

Abnormal mRNA splicing resulting from consensus sequence splicing mutations of ATP7B.

More than 200 Wilson disease (WD) disease-causing mutations have been defined to date. Missense mutations are largely prevalent while splice-site mutations are limited in number. Most reside in the splice donor or acceptor sites and only a minority are detected in splicing consensus sequences. Furthermore, only a few splicing mutations have been studied at the RNA level to date. In this study, using the RT-PCR method we performed the molecular characterization of four consensus splice-site mutations identified by DNA analysis in patients with WD. One of them, previously described 1707+3insT, occurred at position 3 in the donor splice site of intron 4, while the other three, 2122-8T>G, 2866-6T>G, and 3061-12T>A, are novel and occurred in the acceptor splice sites of introns 7, 12, and 13, respectively. Analysis revealed a prevalently abnormal splicing in the samples carrying the mutations compared to the normal controls. Comparison of RNA splicing with normal controls in liver and lymphocytes further suggests that abnormal splicing of the WD gene is also present and differentially regulated in normal tissues. The results produced in this study strongly suggest that DNA mutations residing in the consensus sequence of WD gene splice sites result in the WD phenotype by interfering with the production of the normal WD protein. Further studies are necessary to better quantify the amount of different transcripts produced by these mutations, and establish their correlation with the disease phenotype.

Adenosine Triphosphatases↗
PubMed2002

Pregnancies following blastocyst stage transfer in PGD cycles at risk for beta-thalassaemic haemoglobinopathies.

BACKGROUND: Preimplantation genetic diagnosis (PGD) usually involves blastomere biopsy 3 days post-insemination (p.i.), followed by genetic analysis and transfer of unaffected embryos later on day 3 or 4. We evaluate a strategy involving embryo biopsy on day 3 p.i., genetic analysis on day 4 and, following culture in blastocyst sequential media, transfer of unaffected embryos on day 5 p.i. METHODS: PGD cycles were initiated in 15 couples at risk of transmitting beta-thalassaemia major. Oocyte retrieval and ICSI were performed according to standard protocols. Embryo culture used blastocyst sequential media. Embryos were biopsied on day 3 p.i. using acid Tyrode's for zona drilling, and the single blastomeres were genotyped by a protocol involving nested polymerase chain reaction and denaturing gradient gel electrophoresis analysis. RESULTS: Forty of 109 (37%) embryos biopsied on day 3 p.i. developed to blastocysts by day 5 p.i., with at least one blastocyst available for transfer in 12 cycles (80%). Genotype analysis characterized 51/109 (47%) embryos unaffected for beta-thalassaemia major, of which 28 were blastocysts. Transfer of 37 day 5 p.i. embryos (blastocysts and non blastocysts) initiated eight clinical pregnancies. Implantation rate per embryo transferred was 12/37 (32%). CONCLUSIONS: Embryo biopsy on day 3, followed by delayed transfer until day 5 p.i. offers a novel and effective strategy to overcome the time limit encountered when performing PGD, without compromising embryo implantation.

Biopsy↗
PubMed2002

Preimplantation genetic diagnosis in clinical practice.

Preimplantation genetic diagnosis (PGD) represents an alternative to prenatal diagnosis and allows selection of unaffected IVF embryos for establishing pregnancies in couples at risk for transmitting a genetic disorder.

Chromosome Disorders↗
PubMed2001

Qualitative and quantitative analysis of mRNA associated with four putative splicing mutations (621+3A-->G, 2751+2T-->A, 296+1G-->C, 1717-9T-->C-D565G) and one nonsense mutation (E822X) in the CFTR gene.

The effects of four splicing mutations and one nonsense mutation on cystic fibrosis transmembrane conductance regulator ( CFTR) gene expression were investigated by reverse transcription-polymerase chain reaction analysis of mRNA extracted from nasal epithelial cells harvested from patients harbouring the mutations. We studied four subjects with 621+3A-->G, two with 2751+2T-->A, one with 296+1G-->C, two with 1717-9T-->C-D565G and seven with E822X and compared the results with CFTR mRNA from normal subjects. Our results showed that mutations 621+3A-->G, 2751+2T-->A, and 296+1G-->C, which disrupt the 5' splice donor sites of introns 4, 14a, and 2, respectively, and 1717-9T-->C-D565G, which possibly disrupts the exonic splicing enhancer sequences of exon 12 (owing to the missense mutation in cis), lead to the production of aberrantly spliced mRNA in nasal epithelial cells. Three of the splicing mutations (621+3A-->G, 2751+2T-->A, and 296+1G-->C) result in severe deficiency of normal CFTR mRNA and severe phenotype in the patients. This information is especially useful for mutation 621+3A-->G, which is found in other populations as well, and was initially reported as a polymorphism. The complex allele 1717-9T-->C-D565G results in aberrant splicing of CFTR mRNA with production of transcripts lacking exon 12 (major product), with minor amounts of transcripts revealing joint exon 11 and 12 skipping. Nonsense mutation E822X results in a severe reduction in mRNA levels to about 6% of wild type. Patients with the mutation have a severe clinical phenotype, with both the pancreatic and the pulmonary function affected.

Adolescent↗
PubMed2001

Preimplantation genetic diagnosis (PGD), a collaborative activity of clinical genetic departments and IVF centres.

Preimplantation genetic diagnosis (PGD) requires the combined efforts of geneticists and workers in the field of reproductive medicine. This was studied on the basis of a questionnaire, sent to 35 members of the PGD Consortium of the European Society of Human Reproduction and Embryology (ESHRE). A reply was obtained from 20 centres. They represent the majority of activities in the field of PGD in the world. It is obvious that many of the activities (in vitro fertilisation, embryo culture and biopsy) take place in IVF units while others (counselling and diagnosis) are the responsibility of genetic diagnostic centres. The distances between both units vary considerably. In all but one centre sex determination is offered. Aneuploidy screening is offered in 13 out of 20 centres. PGD of translocations and other structural chromosome abnormalities is offered in all but one centre. The number of monogenic diseases offered varies considerably. In comparison to prenatal diagnosis PGD is more expensive. The majority of these costs are due to the IVF or ICSI procedure. The charges for PGD vary between about 600 euro and 4000 euro. In 16 out of 20 centres the parents to be must sign an informed consent form.

Aneuploidy↗
PubMed2001

CFTR gene mutations--including three novel nucleotide substitutions--and haplotype background in patients with asthma, disseminated bronchiectasis and chronic obstructive pulmonary disease.

In order to investigate the incidence of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations and unclassified variants in chronic pulmonary disease in children and adults, we studied 20 patients with asthma, 19 with disseminated bronchiectasis (DB) of unknown aetiology, and 12 patients with chronic obstructive pulmonary disease (COPD), and compared the results to 52 subjects from the general Greek population. Analysis of the whole coding region of the CFTR gene and its flanking intronic regions revealed that the proportion of CFTR mutations was 45% in asthma (P<0.05), 26.3% in DB (P>0.05), 16.7% in COPD (P>0.05), compared to 15.4% in the general population. Seventeen different molecular defects involved in disease predisposition were identified in 16 patients. Three potentially disease-causing mutations, T388 M, M1R and V11I, are novel, found so far only in three asthma patients. The hyperactive M470 allele was found more frequently in COPD patients (frequency 70.8%, P<0.01) than in the controls. The study of the TGmTnM470 V polyvariant CFTR allele revealed the presence of CFTR function-modulating haplotypes TG13/T5/M470, TG11/T5/M470, TG12/T5/V470 and TG12/T7, combined with M470 or V470, in six asthma patients, four DB patients (P<0.01), and two COPD patients (P<0.05). These results confirm the involvement of the CFTR gene in asthma, DB and possibly in COPD.

Adolescent↗
PubMed2001

Gilbert syndrome associated with beta-thalassemia.

The authors investigated whether the considerable variability in serum bilirubin levels (STB) found in transfusion-dependent beta-thalassemia, beta-thal intermedia, and heterozygous beta-thalassemia individuals could be related to the coexistence of Gilbert syndrome (GS). The promoter region [A(TA)nTAA] of the bilirubin UDP-glucuronosyltransferase gene (UGT1A1) was analyzed in a total of 128 beta-thalassemia individuals (108 transfusion-dependent beta-thal patients, 20 very mild beta-thal intermedia) and in 33 beta-thal heterozygotes. The control group consisted of 70 healthy children with no history of anemia. The frequency of GS genotype (TA)7/(TA)7 did not differ significantly between the groups studied. A significant difference was observed between serum bilirubin levels (STB) and GS genotypes (TA)7/(TA)7 and (TA)6/(TA)7 and also between (TA)7/(TA)7 and (TA)6/(TA)6 for all groups examined. These results confirm that the (TA)7/(TA)7 GS genotype is one of the factors accounting for the hyperbilirubinemia observed in beta-thalassemia major, intermedia, and heterozygous individuals.

Bilirubin↗
PubMed2001

Hb Sitia [beta128(H6)Ala-->Val]: an unstable variant with a substitution in the alpha1beta1 interface.

Hb Sitia [beta128(H6)Ala-->Val] was found in a Greek female with slightly reduced red blood cell indices. The abnormal hemoglobin was indistinguishable from Hb A by electrophoresis but eluted after Hb A on cation exchange high performance liquid chromatography. DNA sequence analysis revealed a GCT-->GTT mutation at codon 128, which is predicted to encode an Ala-->Val substitution. This was confirmed by mass spectrometry analyses of the beta-globin chain. Since alanine at beta128(H6) interacts with several amino acids of the alpha1beta1 contact, its replacement by a larger residue results in a mild instability of the molecule and slight modifications of the oxygen binding properties.

Adult↗
PubMed2001

Different geographic origins of Hb Constant Spring [alpha(2) codon 142 TAA-->CAA].

BACKGROUND AND OBJECTIVES: The occurrence of Hb CS is usually limited to the geographic area which includes Southern China and South East Asia. In 1968 Hb CS was also found to occur in the Mediterranean area where it was originally described as Hb Athens. We investigated the independent origin of these termination codon mutations of the alpha 2-globin gene by determining the alpha-cluster haplotype and comparing the hematologic data from Hb CS-Hb H patients and their family members. DESIGN AND METHODS: We studied one Hb CS-Hb H patient of Greek origin and a Sicilian family in which one individual was affected by Hb CS-Hb H. The haplotype of the Hb CS allele was determined and compared to the haplotype of an Hb CS-Hb H individual of Chinese origin. RESULTS: The haplotype found for the Greek and Sicilian Hb CS was the same but differed significantly from the Asiatic Hb CS mutation. INTERPRETATION AND CONCLUSIONS: The Hb CS mutation found in both Mediterranean patients arose independently in the Mediterranean area. The difference in clinical manifestation of the Hb CS-Hb H disease in both patients is less common but consistent with similar variation in the clinical expression of analogous Hb Icaria-Hb H disease patients.

China↗
PubMed2001

Erythroid marrow activity and functional anemia in patients with the rare interaction of a single functional a-globin and beta-globin gene.

BACKGROUND AND OBJECTIVES: The degree of globin chain imbalance and tissue hypoxia are important determinants of clinical severity in thalassemia syndromes. Thus phenotypic expression may be modified by interaction of alpha- and beta-thalassemia defects, level and type of hemoglobin synthesized and oxygen release to the tissues. We evaluated hematology, erythroid marrow activity and functional anemia in patients with the rare interaction of a single a-globin gene and heterozygous beta-thalassemia (HbH/beta-thal trait). DESIGN AND METHODS: In 7 patients characterized by DNA analysis to have HbH disease genotypes with beta-thalassemia trait, we assessed hematologic findings, serum transferrin receptor (sTfR), serum erythropoietin (Epo), red cell 2,3-disphosphoglycerate (2,3-DPG) and whole blood oxygen releasing capability. RESULTS: Patients with HbH/beta-thal trait had moderate anemia, marked hypochromasia and microcytosis, normal or raised HbA2, and no electrophoretically/chromatographically detectable HbH. Epo and sTfR levels were significantly higher than in beta-thalassemia heterozygotes, but lower than in patients with HbH disease; 2,3-DPG levels were highest in HbH/beta-thal trait. Oxygen binding studies and simulations showed reduced oxygen affinity (P50) in HbH/beta-thal trait, resulting in increased oxygen release (O2R). INTERPRETATION AND CONCLUSIONS: Hematologic findings and bone marrow activity in patients with HbH/b-thal trait were consistent with the modified globin chain imbalance and hemoglobin synthesis expected from interaction of HbH disease with heterozygous b-thalassemia, although this rare complex genotype may elude diagnosis based on hematology alone. Significantly higher red cell 2,3-DPG levels were an unexpected finding, and the consequent increase in oxygen release capability resulted in a compensated functional anemia relative to hemoglobin levels.

Adolescent↗
PubMed2000

Distinct phenotypic expression associated with a new hyperunstable alpha globin variant (Hb heraklion, alpha1cd37(C2)Pro>0): comparison to other alpha-thalassemic hemoglobinopathies.

Clinical phenotypes associated with abnormal globin chain biosynthesis may result in thalassemia (deficient quantity) or hemolytic anemia (abnormal hemoglobins). However, the phenotypic expression of hyperunstable hemoglobin variants often includes features of thalassemia, along with variable peripheral hemolysis. Hemoglobinopathies caused by highly unstable beta-chain variants have a dominant thalassemia-like phenotype, in which carriers have a clinical expression of thalassemia intermedia, but highly unstable alpha-globin variants are usually only phenotypically apparent when they interact with other alpha-thalassemia mutations. In a child with clinical and hematological features consistent with beta-thalassemia intermedia, DNA analysis excluded any beta-globin gene mutations but characterized a novel deletion cd37(C2)Pro>0 (Hb Heraklion) in the alpha1 globin gene, in trans to a common Mediterranean nondeletion alpha-thalassemia mutation (alpha(Hph)alpha). The deletion of proline at alpha37(C2) is predicted to result in severe instability of the variant hemoglobin, which on interaction with a synthesis-deficient alpha-thalassemia mutation causes a relatively severe dyserythropoietic anemia, representing an alternative phenotype associated with highly unstable alpha-chain variants. Hb Heraklion is the fourth highly unstable alpha-globin variant that we have observed in patients from Greece and Albania. Two variants involve the alpha2-globin gene: Hb Agrinio (alpha29(B10)Leu>Pro) and Hb Adana (alpha59(E8)Gly>Asp), and two the alpha1-gene: Hb Aghia Sophia (alpha62(E11)Val>0) and (Hb Heraklion a37(C2)Pro>0). Each has been observed on interaction with a different alpha-thalassemia mutation and the phenotypes associated with these highly unstable alpha-variants are presented.

Adolescent↗