A Novel Mutation in the Promoter Region of the ß-Globin Gene: HBB: c.-127G > C.

Novel ß-globin gene mutations are still occasionally being reported, especially when evaluating milder phenotypes. We report here a novel putative mutation in the promoter region of the ß-globin gene and assess its clinical implications. A family, parents and four siblings, with hematological and clinical features suspected of being ß-globin gene mutation(s), were involved in this study. In addition to hematological and clinical evaluations of the whole family, molecular analyses of the ß-globin gene were performed by direct sequencing. Sequencing of the ß-globin gene revealed a novel genomic alteration in the regulatory region of the gene. This novel genomic alteration was defined as HBB: c.-127G > C according to the Human Genome Variation Society (HGVS) nomenclature. Two siblings were found to be carriers of the HBB: c.-127G > C mutation, while the other two siblings were carriers of the codon 8 (-AA) (HBB: c.25_26delAA) deletion of the ß-globin gene. The mother was a compound heterozygote for the codon 8 and HBB: c.-127G > C mutations. Based on hematological and clinical evaluations, we conclude that this novel ß-globin gene promoter region change would be associated with a mild phenotype of ß-thalassemia (ß-thal).

Gap-PCR Screening for Common Large Deletional Mutations of ß-Globin Gene Cluster Revealed a Higher Prevalence of the Turkish Inversion/Deletion (δß)0 Mutation in Antalya.

OBJECTIVE: Although the calculated carrier frequency for point mutations of the ß-globin gene is around 10% for Antalya Province, nothing is known about the profile of large deletional mutations involving the ß-globin gene. In this study, we aimed to screen common deletional mutations in the ß-globin gene cluster in patients for whom direct DNA sequencing was not able to demonstrate the mutation(s) responsible for the disease phenotype. MATERIALS AND METHODS: Thirty-one index cases selected with a series of selection events among 60 cases without detected ß-globin gene mutation from 580 thalassemia-related cases tested by direct sequencing over the last 4 years in our diagnostic center were screened for the most common 8 different large deletional mutations of the ß-globin gene cluster by gap-PCR. RESULTS: We detected 1 homozygous and 9 heterozygous novel unrelated cases for the Turkish inversion/deletion (δß)0 mutation in our series of 31 cases. Our study showed that the Turkish inversion/deletion (δß)0 mutation per se accounts for 16.6% of the unidentified causative alleles and also accounts for 1.5% of all detected mutations over the last 4 years in our laboratory. CONCLUSION: Since molecular diagnosis of deletional mutations in the ß-globin gene cluster warrants different approaches, it deserves special attention in order to provide prenatal diagnosis and prevention opportunities to the families involved. We conclude that the Turkish inversion/deletion (δß)0, as the most prevalent deletional mutation detected so far, has to be routinely tested for in Antalya, and the gap-PCR approach has valuable diagnostic potential in the patients at risk.

Clinical evaluation of R202Q alteration of MEFV genes in Turkish children.

To date, over 200 alterations have been reported in Mediterranean fever (MEFV) genes, but it is not clear whether all these alterations are disease-causing mutations. This study aims to evaluate the clinical features of the children with R202Q alteration. The medical records of children with R202Q alteration were reviewed retrospectively. A total of 225 children, with 113 males, were included. Fifty-five patients were heterozygous, 30 patients were homozygous for R202Q, and 140 patients were compound heterozygous. Classical familial Mediterranean fever (FMF) phenotype was present in 113 patients: 2 heterozygous and 7 homozygous R202Q, 46 double homozygous R202Q and M694V, and 58 compound heterozygous. The main clinical characteristics of the patients were abdominal pain in 71.5 %, fever in 37.7 %, arthralgia/myalgia in 30.2 %, arthritis in 10.2 %, chest pain in 14.6 % and erysipelas-like erythema in 13.3 %. The frequency of abdominal pain was significantly lower in patients with homozygous R202Q alteration (p = 0.021), whereas patients with heterozygous R202Q mutations, though not statistically significant, had a higher frequency of arthralgia/myalgia (40.0 %, p = 0.05). R202Q alteration of the MEFV gene leads to symptoms consistent with FMF in some cases. This alteration may be associated with a mild phenotype and shows phenotypic differences other than the common MEFV mutations.

MEFV gene mutations in Turkish children with juvenile idiopathic arthritis.

UNLABELLED: Mutations of the Mediterranean fever (MEFV) gene, which encodes pyrin protein, leads to familial Mediterranean fever (FMF) and a connection between MEFV mutations and rheumatic diseases has been suggested. The aim of this study was to explore the frequency and clinical significance of MEFV mutations in children with juvenile idiopathic arthritis (JIA). In this study, children with JIA, who had no typical symptoms of FMF, were screened for the mutations in exons 2 and 10 of the MEFV gene by direct sequencing. A total of 96 children, 56 girls (58.3%), with a median age of 11 years (2-18 years) were included. Patients were classified according to JIA subgroups as oligoarthritis in 43 (44.8%), rheumatoid factor-negative polyarthritis in 22 (22.9%), rheumatoid factor-positive polyarthritis in 2 (2.1%), systemic arthritis in 12 (12.5%) patients, enthesitis-related arthritis in 16 (16.7%), and psoriatic arthritis 1 (1.04%). A total of 31 children (32.3%) had MEFV mutations: 25 heterozygous, 2 homozygous, and 4 compound heterozygous. There were 22 (11.4%) exon 10 mutations (M694V, R761H, K695R, V726A, R653H) and 15 (7.8%) exon 2 mutations (E148Q, G304R, E148V, T267I). The allele frequencies of MEFV mutations were found to be 19.27%, which is higher than the general population [p = 0.03, (odds ratio (OR):1.93, 95% confidence interval (CI): 1.09-3.41)]. MEFV mutation carrier rates were significantly higher in antinuclear antibody (ANA) negative than in ANA positive patients [p = 0.01, (OR: 0.25, 95% CI: 0.085-0.74)] and in males than in females [p = 0.001, (OR: 0.197, 95% CI: 0.078-0.495)]. Also, there was a statistically significant difference between the MEFV mutation carrier rates and the subgroups of JIA (p = 0.005). CONCLUSION: These findings suggest that mutations of the MEFV gene may be responsible for rheumatic diseases other than FMF, and patients with JIA especially males, ANA negatives, and ERA subgroups should be screened for MEFV gene mutations in countries where FMF is frequent.

A patient with Down syndrome with a de novo derivative chromosome 21.

Pure partial trisomy of chromosome 21 is a rare event. The patients with this aberration are very important for setting up precise karyotype-phenotype correlations particularly in Down syndrome phenotype. We present here a patient with Down syndrome with a de novo derivative chromosome 21. Karyotype of the patient was designated as 46,XY,der(21)(p13)dup(21)(q11.2q21.3)dup(21)(q22.2q22.3) with regard to cytogenetic, FISH and array-CGH analyses. Non-continuous monosomic, disomic and trisomic chromosomal segments through the derivative chromosome 21 were detected by array-CGH analysis. STR analyses revealed maternal origin of the de novo derivative chromosome 21. The dual-specificity tyrosine (Y)-phosphorylation regulated kinase 1A (DYRK1A) and Down Syndrome Critical Region 1 (DSCR1) genes that are located in Down syndrome critical region, are supposed to be responsible for most of the clinical findings of Down syndrome. However, our patient is the first patient with Down syndrome whose clinical findings were provided in detail, with a de novo derivative chromosome 21 resulting from multiple chromosome breaks excluding DYRK1A and DSCR1 gene regions.

The association between intragenic SNP haplotypes and mutations of the beta globin gene in a Turkish population.

Identification of the beta globin gene mutation-related haplotypes is of interest for the delineation of the clinical heterogeneity as well as understanding of the origin and spreading of the beta globin gene mutations. We screened the whole beta globin gene in 197 Turkish patients by direct sequencing and performed Haploview analyses for beta globin gene haplotyping using five common intragenic SNPs; rs713040, rs10768683, rs7480526, rs7946748, and rs1609812. We found 25 different beta globin gene point mutations by sequencing. A Turkish type of inv/del mutation by MLPA and Gap-PCR was also detected with additional studies. The seven most common mutations with higher frequency of 5% were IVS-I-110 (G>A) (35.6%), Hb S(10.6%), IVS-I-6 (T>C) (7.4%), IVS-I-1 (G>A) (6.9%), IVS-II-1 (G>A) (6.9%), Cod8(-AA) (6%), IVS-II-745 (C>G) (5.1%) and accounted for 78.7% of all mutations. We identified seven different haplotypes (Haplotype I-VII) using five intragenic single nucleotide polymorphisms (SNPs) genotyped by sequencing of the beta globin gene. The association between the mutations and the haplotypes was defined for 16 different mutations. We suggest that haplotyping by these five intragenic SNPs will provide useful information about the origin of the mutations and gene flow among as well as the explanation of the clinical heterogeneity.

Pure and complete 12p trisomy due to a maternal centric fission of chromosome 12.

Pure and complete 12p trisomy are rare. Here, we report on a unique patient with trisomy 12p syndrome due to centric fission of maternal chromosome 12. Conventional cytogenetic and fluorescence in situ hybridization (FISH) techniques revealed the proposita's karyotype to be 47,XX,+fis(12)(p10)mat whereas the maternal one was 47,XX,-12,+fis(12)(p10),+fis(12) (q10). This is the first report on centric fission of chromosome 12 leading to stable telocentrics, each with a fully functional centromere. Our observation shows that the centric fission of chromosome 12 can be a new mechanism for generation of a partial centromere and trisomy 12p syndrome.

Prenatal diagnosis of ß-thalassemia and other hemoglobinopathies in southwestern Turkey.

Our aim was to evaluate the prenatal diagnosis of ß-thalassemia (ß-thal) and other hemoglobinopathies in a region with high frequency. After detection by premarital or antenatal screening, 312 patients underwent 420 prenatal diagnostic procedures for 407 fetuses in a 10-year period. Fetal samples were collected by chorionic villi sampling (CVS) in the first trimester and amniocentesis and cordocentesis in the second trimester. Mutation analyses of ß-globin and cytogenetic analyses were performed and the most common mutations detected were: IVS-I-110 (G>A), IVS-II-1 (G>A), IVS-I-6 (T>C) and IVS-II-745 (C>G). Hb S [ß6(A3)Glu→Val, GAG>GTG)] was the most common hemoglobin (Hb) variant with a frequency of 6.3%. Among 407 fetuses, 105 (25.8%) were diagnosed as affected, while 201 (49.4%) were carriers and 101 (24.8%) were normal. Cytogenetic analyses revealed nine fetuses (2.3%) with numerical chromosomal abnormalities as regular or mosaicism. Prenatal diagnosis of common hemoglobinopathies is safe and effective. Performing cytogenetic analysis in excess fetal material is an acceptable option.

The effect of HBB: c.*+96T>C (3'UTR +1570 T>C) on the mild b-thalassemia intermedia phenotype.

Hemoglobin beta (HBB): c.*+96T>C substitution is very rare among ß-globin gene mutations and its clinical significance remains to be clarified. The present study aimed to investigate the role of HBB: c.*+96T>C in the ß-thalassemia intermedia phenotype in a Turkish family. The proband and parents were screened for ß-globin gene mutations via direct sequencing. Hematological and physical examination results were recorded, and correlated according to genotype. The proband was compound heterozygous for Cod 8 (-AA) and HBB: c.*+96T>C, whereas his mother and father were heterozygous for Cod 8 (-AA) and HBB: c.*+96T>C, respectively. The father had almost normal hematological findings, whereas the mother had the typical ß-thalassemia trait phenotype. The proband was diagnosed as mild ß-thalassemia intermedia based on hepatosplenomegaly and hematological findings. To the best of our knowledge this is the first report of HBB: c.*+96T>C mutation in a Turkish family. HBB: c.* 96T>C substitution is a very rare, but clinically relevant ß-globin gene mutation. Additionally, we think that if 1 spouse is a carrier for ß-globin gene mutation the other should be screened for silent mutations, such as HBB: c.*+96T>C mutation of the ß-globin gene, even if she/he does not have any clinical or hematological signs of the ß-thalassemia trait phenotype.

The association between inherited thrombophilias and pregnancy-related hypertension recurrence.

PURPOSE: The aim of this study was to determine the association between inherited thrombophilias and pregnancy-related hypertension recurrence. METHODS: In this case-control study, blood samples were obtained from patients who had at least two pregnancies complicated with pregnancy-related hypertension (n = 41) and healthy, normotensive pregnancies delivered without any complication (n = 38). Following the DNA extraction, samples were tested for factor V Leiden, prothrombin G20210A and homozygous methylene tetrahydrofolate reductase (MTHFR) C677T mutations using reverse hybridization method. RESULTS: Common inherited thrombophilias were present in 26.8% of women with recurrent pregnancy-related hypertension group and 23.7% of control subjects (odds ratio 1.1; 95% confidence interval, 0.6-1.9). No significant difference was observed between two groups in terms of factor V Leiden, prothrombin G20210A and MTHFR C677T mutations. CONCLUSION: Our data suggest that factor V Leiden, prothrombin G20210A and MTHFR C677T mutations are not associated with pregnancy-related hypertension recurrence.

Evaluation of congenital heart diseases and thyroid abnormalities in children with Down syndrome.

OBJECTIVE: Congenital heart disease (CHD) associated with thyroid disease has been reported in Down syndrome (DS). The purpose of this work was to assess abnormalities of the thyroid in relation to the frequency and type of CHD on admission among children with DS. METHODS: This retrospective study included 187 children with DS between August 1993- December 2005. Karyotype analysis, thyroid function tests and echocardiographic studies were performed in all children with DS. If necessary, hemodynamic study by catheterization was carried out. Thyrotropin releasing hormone (TRH) stimulation test was performed in having elevated thyroid stimulating hormone (TSH) level. Statistical analyses were performed using Chi-square, "t" test for independent samples or Mann-Whitney U test. RESULTS: It was found that 136 (72.73%) patients with DS had CHD. The age difference at the time of admission was statistically significant for these two groups (p=0.001) in children with /without CHD. There were 12 (11.88%) patients with congenital hypothyroidism and DS, of whom 11 had CHD. There were statistically significant differences in the levels of TSH and total thyroxine (tT4) between congenital and subclinical hypothyroid and euthyroid groups (p=0.001 for TSH and p= 0.001 for tT4). But, there was no significant relationship between having any kind of CHD and levels of TSH and tT4. CONCLUSION: Our data suggest that all patients with DS should be evaluated with careful physical and echocardiographic examination on admission. In addition, congenital or subclinical hypothyroidism should also be kept in mind in children with DS and monitored accordingly.

The effect of CYP1A2 gene polymorphisms on Theophylline metabolism and chronic obstructive pulmonary disease in Turkish patients.

Cytochrome P450 (CYP) 1A2 gene polymorphisms are thought to be involved in the metabolism of theophylline (TP). We aimed to investigate the effect of CYP1A2*1C, CYP1A2*1D, CYP1A2*1E, and CYP1A2*1F polymorphisms of the CYP1A2 on TP metabolism by PCR-RFLP in 100 Turkish patients with chronic obstructive pulmonary disease (COPD) receiving TP. One hundred and one healthy volunteers were included as control group. The genotype frequencies of the CYP1A2*1D and CYP1A2*1F were found to be significantly different in the patients compared to the controls. The "T" allele at -2467 delT and the "C" allele at -163 C > A in the CYP1A2 displayed association with a significantly increased risk for COPD. "T" allele at - 2467 delT was also associated with a high risk of disease severity in COPD. In conclusion, our data suggest that genetic alterations in CYP1A2 may play a role both in the pharmacogenetics of TP and in the development of COPD.

Insertion/deletion polymorphism and serum activity of the angiotensin-converting enzyme in Turkish patients with obstructive sleep apnea syndrome.

This study determined the allelic frequency and genotypic distribution of an angiotensin-converting enzyme (ACE) polymorphism and serum ACE activity in Turkish patients with obstructive sleep apnea syndrome (OSAS). A colorimetric assay measured serum ACE activity in 73 of 97 subjects. Frequencies for II, ID, and DD genotypes were 19.6, 53.6, and 26.8% in the OSAS group and 15, 38, and 47% in the control group, respectively (P = 0.02). The I allele frequency was higher in the OSAS group than in the healthy control group (P = 0.02). Carrying the I allele (II or ID genotypes) increased OSAS risk 2.41 times in the Turkish population. Mean ACE activity was significantly lower in patients with the II genotype than in the DD genotype (P = 0.011), and ACE activity was significantly lower in patients with severe OSAS than in those with mild OSAS (P = 0.006). Our results suggest that II and ID genotypes of the ACE gene increase the risk of developing OSAS in the Turkish population.

Neutrophil oxidative metabolism in Down syndrome patients with congenital heart defects.

Down syndrome (DS) occurs when an individual has three, rather than two, copies of the 21st chromosome. Cytosolic superoxide dismutase (SOD-1) is encoded by a gene on chromosome 21 and thus, SOD-1 activity is elevated in patients with DS. Forty percent of all cases with DS are associated with congenital heart defects (CHD). Although the contribution of SOD1 to disease phenotype is unknown, it is considered to be a "molecular marker" of the disease. It was hypothesized herein that the presence of CHD may alter the expression of SOD1 and oxidative metabolism in patients with DS. This hypothesis was tested via four experimental groups as follows: patients with DS without CHD, DS patients with CHD, CHD patients without DS and controls. Expression and activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), myeloperoxidase (MPO), and catalase (CAT) were determined in neutrophils from all experimental groups. Intracellular hydrogen peroxide concentration and superoxide release were also evaluated in neutrophils. A significant increase was observed in SOD and GPx amount and activity in patients with DS with and without CHD. No significant difference was found in the amount and activity of MPO and CAT among the different experimental groups. Intracellular hydrogen peroxide concentration was similar in all groups, whereas a prominent decrease was seen in superoxide release in cases with DS. Patients with DS with and without CHD showed no significant differences in any of the measured parameters. The data suggest that CHD observed in patients with DS does not result from altered redox metabolism associated with the disease.

Subtelomeric rearrangements of dysmorphic children with idiopathic mental retardation reveal 8 different chromosomal anomalies.

Subtelomeric rearrangements are an important cause of both sporadic and familial idiopathic mental retardation (MR) and/or congenital malformation syndromes. We report on a cohort of 107 children with idiopathic MR and normal karyotype 450-550 band level by GTG banding screened for subtelomeric rearrangements by multiprobe fluorescence in situ hybridization (FISH). In these cases, five patients had de novo deletions (1p deletion was found in 2 cases; 3q deletion, 9p and 9q deletions were found in 1 case each) and four patients had unbalanced rearrangements [der(5)t(5;15)(pter;qter)pat in 2 patients who were siblings, rec(10)dup(10p)inv(10)(p13q26)mat in 1 patient and der(18)t(18;22)(qter;qter) de novo in 1 patient]. Our study confirms that the subtelomeric rearrangements are a significant cause of idiopathic MR with dysmorphic features.

DNA gains and losses of chromosome in laryngeal squamous cell carcinoma using comparative genomic hybridization.

PURPOSE: A larynx squamous cell carcinoma (LSCC) is one of the most common forms of cancer and may exhibit various complex karyotypes. MATERIALS AND METHODS: We used comparative genomic hybridization (CGH) to analyze DNA gains and losses in 15 squamous cell carcinomas that consisted of 4 glottic, 10 supraglottic, and 1 transglottic localization samples. RESULTS: The majority of the chromosomal alterations detected were gains: 3 samples of LSCCs revealed high level amplification, while 6 samples displayed gains in various chromosomal regions (17p, 3p, 4p, 5p, 6q, 8p, 9p, 14q, 18p and Xq). One sample was found to have losses (chromosomes 15q and 22q) and 5 had normal CGH profiles. CONCLUSION: Many of these gained regions (4p, 5p, 8p, 10q, 18q and Xq) were novel sites, which may harbor oncogene(s) that potentially play an important role in squamous cell tumorigenesis and progression at supraglottic localizations.

Effects of hormone replacement therapy on bone mineral density in Turkish patients with or without COL1A1 Sp1 binding site polymorphism.

AIM: To evaluate the effects of hormone replacement therapy (HRT) on bone mineral density (BMD) in patients with or without COL1A1 Sp1 binding site polymorphism. METHODS: Non-smoking otherwise healthy postmenopausal women (n=111), who had not received any kind of HRT for at least 3 years (between 2002 and 2005) at the onset of menopause, were included. All patients received 0.625 mg conjugated estrogen/2.5 mg medroxyprogesterone for 18 months. BMD by dual X-ray absorptiometry was measured at the lumbar spine and the femur neck initially and after 18th months of treatment. COL1A1 Sp1 binding site polymorphism was studied using the PCR-RFLP method. RESULTS: After having the results of COL1A1 Sp1 binding site polymorphism, 79 (71.2%) patients were SS, 30(27.0%) were Ss and two (1.8%) were homozygous for ss. The mean age, weight and length of menopausal period were similar between the SS and Ss patients. The Ss heterozygotes had lower BMD values both at the lumbar spine and at the femur neck compared with the SS patients. This difference was also reflected in post treatment measurements. The increase in BMD scores was higher in the SS homozygotes than in the Ss patients. CONCLUSION: Our preliminary data supports the fact that HRT had a lower increase in BMD scores following 18 months of treatment in COL1A1 s allele individuals compared with normal SS individuals. Therefore our study may provide evidence that the Sp1 polymorphism may ameliorate the effects of HRT on BMD, suggesting some additional regimens may be used to support bone strength and to decrease osteoporotic fractures.

Relationship between SP1 polymorphism and osteoporosis in beta-thalassemia major patients.

BACKGROUND: beta-Thalassemia is an autosomal recessive disease characterized by defective beta-globin chain production. Osteoporosis is an important cause of morbidity in patients with beta-thalassemia major. The pathogenesis of reduced bone mineral density (BMD) is multifactorial. A range of genetics factors have been implicated in other populations of patients with osteoporosis. Polymorphism at the Sp1 binding site of the collagen type I A1 (COLIA1) gene is thought to be an important factor in the development of osteoporosis. METHODS: Alleles S and s, detected by presence of a G or T nucleotide, respectively in a regulatory site of the COLIA1 gene were investigated in 37 beta-thalassemia major patients with osteoporosis and 92 controls without osteoporosis or osteopenia using polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Fifteen and nine beta-thalassemia major patients displayed SS and Ss genotypes, respectively, whereas 13 were found to have an ss genotype. The mean BMD of the beta-thalassemia major patients with ss genotype was similar to those with the Ss and SS genotypes. In the control group, 77 and 15 subjects had SS and Ss genotypes, respectively, with no ss genotype. Allelic and genotypic distribution in patients were significantly different from controls. CONCLUSION: Determining base substitutions at the Sp1 binding site on the COLIA1 gene in early years may be important in preventing osteoporosis in children with beta-thalassemia major.