Beta thalassemia IVS-I-5(G-->C) heterozygosity masked by the presence of HbJ-Meerut in a Dutch-Indian patient

We describe the genotype/phenotype correlation in a 35 year old anemic female referred to our laboratory because a fast eluting minor fraction on HPLC, mild hemolysis and hematological parameters suggesting a Thalassemia trait, eventually in combination with iron depletion. Direct sequencing of the alpha globin genes revealed heterozygosity for HbJ-Meerut, a Glu-->Ala substitution at residue 120 not justifying the hematological parameters. No other point mutations were found on the alpha genes and Gap-PCR excluded the 6 common deletion defects. Direct sequencing of the beta-globin genes revealed the IVS-I-5 (G-->C) transversion in absence of the elevated HbA2 levels usually measured in carriers of this beta-Thalassemia mutation. The HbA2 tetramer in the presence of HbJ-Meerut divides in two parts. One alphaN2/delta2 migrating on the right spot on HPLC. The other alphaJ2/delta2 migrating under the HbA fraction. Classic alkaline electrophoresis and the modern capillary electrophoresis CE showed these two tetramers and the reduction of the elevated HbA2 level of the beta-Thalassemia trait by at least 20% due to HbA2 Meerut.

Cœur pulmonaire chronique postembolique révélant une bêtathalassémie intermédiaire après splénectomie

INTRODUCTION

The clinical expression of beta-thalassemia intermedia is variable and complications are more frequent than in the minor form. Thromboembolism risk increase after splenectomy. Few cases of the type of complications are reported.

CASE RECORD

A man was admitted for beta-thalassemia intermedia with moderate chronic hemolysis anemia, complicated by chronic pulmonary thromboembolism and liver iron overload. Post-traumatic splenectomy probably increase the risk of this two complications. The patient's respiratory status improved following bosentan therapy without worsening his hepatopathy.

CONCLUSION

The present study also notes that thromboembolism complications can be an indicator of beta thalassemia and interrogate about the risk and the benefit of splenectomy in the treatment of beta-thalassemia intermedia.

Pubertal evaluation of adolescent boys with beta-thalassemia major and delayed puberty

OBJECTIVE

To examine the hormonal status of the hypothalamic-pituitary-gonadal axis in adolescent males with beta-thalassemia major.

DESIGN

Controlled clinical study.

SETTING

Tertiary referral teaching hospital.

PATIENT(S)

Thirty-three adolescent males with beta-thalassemia major.

INTERVENTION(S)

Basal LH, FSH, and T were examined. All individuals received 100 microg GnRH analogue. Four hours later the hormone levels were retested. Patients with beta-thalassemia and low T levels received hCG.

MAIN OUTCOME MEASURE(S)

The preintervention and postintervention levels of FSH, LH, and T were examined.

RESULT(S)

Of the 33 beta-thalassemia major adolescents, 17 had delayed puberty. The difference in basal LH, FSH, and T levels between delayed and normal puberty beta-thalassemia groups were statistically significant. These levels were significantly lower compared with the constitutional delayed puberty group and become even more significant after GnRH analogue administration. The T levels in the beta-thalassemia group were significantly lower than in the control group. After hCG administration, the T levels remained significantly lower in the delayed-puberty beta-thalassemia compared to the normal-puberty beta-thalassemia group.

CONCLUSION(S)

Despite recent therapeutic advances in the management of beta-thalassemia major, the risk of secondary endocrine dysfunction remains high. Hypogonadism is one of the most frequent endocrine complications.

Correlation of echocardiography parameters with cardiac magnetic resonance imaging in transfusion-dependent thalassaemia major

BACKGROUND AND OBJECTIVE

Heart iron load (cardiac Fe) can be indirectly quantified by cardiac magnetic resonance (CMR) T2*. CMR accessibility is limited, whereas echocardiography (Echo) is relatively inexpensive and readily available. The objective was to find Echo parameters that may be useful for predicting cardiac Fe.

DESIGN AND METHODS

We compared a number of parameters derived from Echo to cardiac Fe in 142 thalassaemia major patients who had undergone a CMR study.

RESULTS

All patients with decreased left ventricular (LV) function had cardiac Fe. After removing those patients from the analysis, the total diameter index (Tdi) >5.57 cms/m2, left atrial diameter index >2.41 cm/m2, and the diastolic parameter E/A > 1.96 were highly specific (91.4%, 97.1% and 96.9% respectively) but had low sensitivity (31.8%, 20.45% and 21.8%) in predicting iron load. A right ventricular index >1.47 cm/m2, LV systolic index >2.26 cm/m2 or Tdi >6.26 cm/m2 discriminated between patients with no, or mild to moderate cardiac Fe from those with heavy load, with specificity of 91%, 98.5%, and 98.5%, respectively, but with low sensitivity.

INTERPRETATION AND CONCLUSIONS

Echo parameters for cardiac Fe prediction have restricted value, whereas CMR is essential to assess cardiac Fe. However, patients with decreased LV systolic function should be considered a priori as having cardiac Fe, and chelation therapy should be intensified. This also applies to patients who have the above-described Echo criterion values, even if CMR is not available. Once a patient is found by CMR to have cardiac Fe, then the above Echo criterion values may be useful for ongoing monitoring.

Brain natriuretic peptide as marker of myocardial iron load in beta-thalassemia

Cardiomyopathy due to iron overload represents a frequent life-limiting complication in patients with beta-thalassemia major. We have conducted a study which proved that brain natriuretic peptide plasma levels have high sensitivity and negative predictive value in detecting cardiac hemosiderosis.

Multi-center validation of the transferability of the magnetic resonance T2* technique for the quantification of tissue iron

The transferability of the T2* technique for measurement of tissue iron between magnetic resonance (MR) scanners is unknown. Heart and liver multi-breath-hold T2* sequences were installed on MR scanners at six different sites. T2* was assessed locally in five or more patients with thalassemia major (n=39), and subjects were re-scanned at the standardization center in London. Inter-center reproducibility of T2* in heart and liver was 5.0% and 7.1%, with mean absolute differences in T2* of 1.3 ms and 0.45 ms, respectively. The MR multi-breath-hold T2* technique for tissue iron quantification is transferable between scanners with good reproducibility.

[Identification of fetal nucleated erythrocytes in maternal blood using short tandem repeat typing after primer extension preamplification]

OBJECTIVE

To develop a method for identifying fetal nucleated erythrocytes (NRBCs) in maternal blood.

METHODS

NRBCs in maternal blood were detected by benzidine staining and collected by micromanipulation. After primer extension preamplification (PEP) of the entire genome from a single NRBC, short tandem repeat (STR) genotype was analysed after further amplification of this gene. Single NRBC was differentiated as fetal or maternal origin by comparison of STR genotype of NRBC with its corresponding parents.

RESULTS

NRBCs were found in all of 28 pregnant women in a range of 4 to 13 per 5 ml venous blood. About 43. 6% of NRBCs were determined to be fetal origin by STR typing.

CONCLUSION

This method provides effective identification of fetal NRBCs and allows non-invasive prenatal genetic diagnosis using single fetal NRBC.

Observation of a rare hemoglobin variant [Hb Lulu island, beta107(G9)Gly-->Asp, GGC-->GAC] co-inherited with a beta+-thalassemia mutation [IVS-I-110 (G-->A)] or in the heterozygous state in a Greek-Albanian family

We report clinical, hematological, biochemical, functional and molecular studies carried out on two first cousins from a Greek-Albanian family who have clinical and hematological findings consistent with the diagnosis of thalassemia intermedia. DNA studies determined that they had co-inherited a common Mediterranean beta-thalassemia (thal) mutation, IVS-I-110 (G-->A), in trans to a beta-globin gene mutation at codon 107 (GGC-->GAC), predicted to give rise to a rare unstable beta chain variant Hb Lulu Island or beta107(G9)Gly-->Asp.

[Study on the screening program of thalassemia and the genotype and hematologic parameter among people of productive age in a village, Nanning Guangxi]

OBJECTIVE

To investigate the carrier ratio and the genotype of thalassemia in the rural people of reproductive age in Nanning, and to analyze the characteristics of hematologic parameter in thalassemia carriers.

METHODS

2044 cases of productive age youths were detected with hemoglobin autoanalyse-Variant (HPLC) and Cell Dyn 1700 automatic hemocyte analysator. Among them,430 cases (75 couples randomly selected in thalassemia screening, 140 couples who were told that one or both of them were positive for thalassemia phenotype through hemocyte analysis) carried out thalassemia gene detection in synchronism.

RESULTS

163 cases were detected beta-thalassemia and the thus beta-thalassemia carrier ratio was 7.97%. 13 cases were detected HbH disease, and 2 cases Hb Manitoba, 2 cases HbJ, and 1 case HbQ. As for genotypes,-alpha (3.7)/alpha,-alpha(CS)/alphaalpha and -alpha(WS)/alphaalpha were common ones with in alpha-thalassemia-2, --(SEA)/alphaalpha the most common one in alpha-thalassemia-1, and 41-42 were the most common ones in beta-thalassemia heterozygotes. The detection ratio of alpha,beta combination thalassemia was also relatively high. Mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were low in all cases of HbH disease and beta-thalassemia, also low in 86 cases of alpha-thalassemia-1 with the exception of normal MCH in 1 case, yet normal in 17 cases out of 66 cases of alpha-thalassemia-2. HbF raised in 32 cases out of 69 cases of beta-thalassemia heterozygote, no case showed raised HbF without the raise of HbA2. Hematologic characteristic of alpha, beta combination thalassemia was mainly caused by beta-thalassemia.

CONCLUSION

Carrier ratio of thalassemia in rural productive age youths in Nanning was high while alpha-thalassemia-2 with the genotype -alpha(WS)/alphaalpha and -alpha(CS)/ alphaalpha were common. To those with low MCV and MCH in high-risk region, thalassemia should be suspected.

Prenatal diagnosis of β-thalassemia in Southern China

OBJECTIVE

To control the birth of thalassemic children in Southern China.

STUDY DESIGN

DNA-based diagnosis was offered on fetal tissues in pregnancies when beta-globin gene mutations were identifiable in both parents using polymerase chain reaction (PCR)-reverse dot blot (RDB) assay. An automated high-performance liquid chromatography (HPLC) system was used to analyze fetal hemoglobin in pregnancies when mutation was unidentified in at least one parent. Fetal samplings were collected by chorionic villi sampling (CVS) in the first trimester, and by amniocentesis or cordocentesis in the second trimester. Maternal contamination of fetal DNA was ruled out by short tandem repeats (STR) analysis.

RESULTS

Five hundered and forty-five fetuses of 540 at-risk pregnancies were performed prenatal diagnosis. Out of 540 fetuses tested by DNA analysis, 150 were found to be normal, 257 were carriers, whereas 133 were affected. Out of five fetuses diagnosed by HPLC, one fetus was affected and four were unaffected. Totally, 133 pregnancies with affected fetuses, except for one twin pregnancy, were voluntarily terminated, leading to a marked reduction of severe beta-thalassemia in this region.

CONCLUSIONS

Our prenatal diagnosis strategy proved to be highly effective. DNA- and HPLC-based testing could enable prenatal diagnosis of beta-thalassemia in all at-risk pregnancies.

Cell-Free DNA in Maternal Plasma: Is It All a Question of Size?

Fetal cell-free DNA (cf-DNA) represents only a small fraction of the total cf-DNA in maternal plasma. This feature has rendered it difficult to reliably distinguish fetal alleles which are not very disparate from maternal ones, such as those involving point mutations, by conventional polymerase chain reaction (PCR)-based approaches. It has recently been shown that cell-free fetal DNA molecules have a smaller size than comparable cf-DNA molecules of maternal origin, and that this feature can be exploited for the selective enrichment of fetal DNA sequences, thereby permitting the detection of otherwise masked fetal genetic traits. By the use of this approach, we have shown that it is possible to detect fetal genetic loci for microsatellite markers, as well as point mutations involved in disorders such as achondroplasia and beta-thalassemia.

MRI detects myocardial iron in the human heart

Iron-induced cardiac dysfunction is a leading cause of death in transfusion-dependent anemia. MRI relaxation rates R2(1/T2) and R2*(1/T2*) accurately predict liver iron concentration, but their ability to predict cardiac iron has been challenged by some investigators. Studies in animal models support similar R2 and R2* behavior with heart and liver iron, but human studies are lacking. To determine the relationship between MRI relaxivities and cardiac iron, regional variations in R2 and R2* were compared with iron distribution in one freshly deceased, unfixed, iron-loaded heart. R2 and R2* were proportionally related to regional iron concentrations and highly concordant with one another within the interventricular septum. A comparison of postmortem and in vitro measurements supports the notion that cardiac R2* should be assessed in the septum rather than the whole heart. These data, along with measurements from controls, provide bounds on MRI-iron calibration curves in human heart and further support the clinical use of cardiac MRI in iron-overload syndromes.

The codon 37 (TGG-->TAG) beta(0)-thalassemia mutation found in a Chinese family

We have found an example of the nonsense beta-thalassemia (thal) mutation at codon 37 (TGG-->TAG; Trp-->Stop) in a Chinese family. The fetus, who inherited both parents' beta-thalassemic alleles, was a compound heterozygote for the codons 41/42 (-TCTT) and codon 37 (TGG-->TAG) mutations, and presented with the phenotype of severe beta-thal.

Prevalence and hematological characteristics of beta-thalassemia trait in Gaziantep urban area, Turkey

Thalassemia is one of the most common hereditary disorders in the Mediterranean region and studies have shown that the prevalence of beta-thalassemia trait is high in the southern part of Turkey. Gaziantep is a city located near this region and, therefore, the authors investigated the prevalence and hematological characteristics of the beta-thalassemia traits in primary school students in Gaziantep. Sixty primary schools were selected from a list of all primary schools using a systematic sampling method. Data were collected by a face-to-face questionnaire. Osmotic fragility testing (OFT) using single-tube 0.36% NaCl solution was used for the screening of beta-thalassemia. Students who were positive in regard to OFT went through a series of testing, including a complete blood count, serum ferritin levels, serum iron, and hemoglobin electroforesis. Chi-square test was used in statistical analysis. Of the 2439 students enrolled to the study from the selected 60 classrooms, 1353 (55.5%) were male and 1086 (44.5%) were female. The OFT was positive in 115 (4.7%) of the participants. CEA and confirmatory HPLC results of the students who were positive OFT indicated that 70 (60.8%) had normal results, 33(28.7%) showed high HbA2 levels, 7 (6.1%) showed high HbA2 and HbF levels, 5(5.2%) showed high HbA2 and Fe-deficiency anemia, and none showed increased HbF levels. The overall prevalence of beta-thalassemia trait was 1.84%. No gender differentials and highest rates among the Kahramanmaras (3.5%) and Sanliurfa (1.7%) born students were the other significant findings of this study. Implementation of a routine carrier-screening program offering genetic counseling, prenatal diagnosis, and selective termination of affected fetuses would be a wise approach to eliminate this disease from the region.

[Beta(o)/beta(o) thalassemia with a mild phenotype]

We report the case of a 30 years old patient of Algerian origin, presenting a beta-thalassemia major with a phenotype of intermediate severity. Its genotype is beta(o)/beta(o), leading to a complete absence of beta-globin synthesis. This genotype is usually responsible for major clinical complications and a severe anaemia requiring regular transfusions. However, the patient presents with a mild form of the disease and a moderate relatively well tolerated anaemia. This phenotype was found related to a high level of synthesis of foetal haemoglobin, dependent most probably on an homozygous state for the polymorphism (XmnI -158, C>T) in the promoter of the Ggamma gene. This observation shows that it is important to keep in mind that beta-thalassemia major may have a mild or intermediate phenotype because of polymorphisms of the beta locus.

Analysis of intelligence quotient in patients with homozygous beta-thalassemia

OBJECTIVE

To compare the intelligence quotient (IQ) of patients with thalassemia major (TM) to that of normal children.

METHODS

We conducted the study in April and May 2002 on 294 homozygote beta-thalassemia patients, (157 male and 137 female, mean age of 13.2 years; range, 9-18 years). These 294 patients were randomly selected from the 984 TM patients who routinely refer to Shiraz Cooley's Medical Center in Dastgheyb Hospital, Iran for blood transfusion. Another 294 subjects age and gender matched control group were studied. Intelligence quotients were computed using the Ravin test.

RESULTS

The mean IQ score +/- standard deviation (SD) in the thalassemia group was 109.83 +/- 15.94. This score revealed no statistically significant difference with the control group's score (p<=0.079). A correlation existed between the thalassemia patients' IQ and their level of education (p<0.049).

CONCLUSION

The IQ of TM patients does not differ significantly from the normal population.

A successful strategy for Preimplantation Genetic Diagnosis of beta-thalassemia and simultaneous detection of Down's syndrome using multiplex fluorescent PCR

OBJECTIVES

Preimplantation Genetic Diagnosis (PGD) is an alternative to prenatal diagnosis providing couples the chance to start a pregnancy with an unaffected fetus. The objective of the present study was to develop and apply quick, sensitive and accurate single cell PCR protocols for PGD of beta-thalassemia and Down's syndrome detection.

MATERIAL AND METHOD

Two couples carrying beta-thalassemia codon41-42 mutation underwent routine IVF procedures. Embryo biopsy was performed on Day-3 post-fertilisation and single cell multiplex fluorescent PCR was employed for mutation analysis, contamination detection and diagnosis of trisomy 21 cases.

RESULTS

Seventeen embryos were tested in two clinical PGD cycles. This resulted in the first birth following PGD for a single gene disorder in Thailand and South East Asia, confirmed by prenatal testing. Two embryos were shown to be affected by Down's syndrome.

CONCLUSION

Successful strategy for PGD of beta-thalassemia and Down's syndrome detection using multiplex fluorescent PCR was introduced.

Changes in the Approach for Invasive Prenatal Diagnosis in 35,127 Cases at a Single Center from 1977 to 2004

OBJECTIVES

To evaluate the changes in the approaches used for invasive prenatal diagnosis for beta-thalassemia and karyotyping at a single center from 1977 to 2004.

METHODS

For beta-thalassemia, in 1977 placentacentesis, in 1982 amniocentesis, in 1983 fetoscopy and cordocentesis, in 1983 trancervical chorionic villi sampling (TC-CVS), in 1984 cardiocentesis, in 1986 transabdominal CVS, and in 2002 preimplantation genetic diagnosis (PGD) were introduced. For karyotyping, in 1977 amniocentesis, in 1983 cordocentesis and cardiocentesis and TC-CVS, in 1986 TA-CVS and in 1991 hepatic vein sampling were introduced. Rates of approaches used were retrospectively considered, for 5 different groups (1977-1981; 1982-1985; 1986-1993; 1994-1999; 2000-2004).

RESULTS

35,127 invasive prenatal diagnoses were considered, and 42 PGD included. For beta-thalassemia 6,547 diagnoses were performed and 42 PGD. Since 1986-1993, TA-CVS was the only approach used except for 42 PGD in the 2000-2004 group. For karyotyping 28,538 diagnoses were performed. Amniocentesis and TA-CVS have been the most frequently used in the last years, while cordocentesis and hepatic vein sampling have shown a decline after their introduction.

CONCLUSION

TA-CVS is now the only technique used for beta-thalassemia. For karyotype, amniocentesis and TA-CVS are the most frequently used procedures. Obstetrical and laboratory experience, the availability of screening, and other individual factors, have influenced the choice, towards an earlier approach in pregnancy.

R2 relaxometry with MRI for the quantification of tissue iron overload in beta-thalassemic patients

PURPOSE

To evaluate the usefulness of a time-efficient MRI method for the quantitative determination of tissue iron in the liver and heart of beta-thalassemic patients using spin-spin relaxation rate, R2, measurements.

MATERIALS AND METHODS

Images were obtained at 1.5 T from aqueous Gd-DTPA solutions (0.106-8 mM) and from the liver and heart of 46 beta-thalassemic patients and 10 controls. The imaging sequence used was a respiratory-triggered 16-echo Carr-Purcell-Meiboom-Gill (CPMG) spin-echo (SE) pulse sequence (TR = 2000 msec, TE(min) = 5 msec, echo spacing (ES) = 5 msec, matrix = 192 x 256, slice thickness = 10 mm). Liver iron concentration (LIC) measurements were obtained for 22 patients through biopsy specimens excised from the relevant liver segment. Biopsy specimens were also evaluated regarding iron grade and fibrosis. Serum ferritin (SF) measurements were obtained in all patients.

RESULTS

A statistically significant difference was found between patients and healthy controls in mean liver (P < 0.004) and myocardium (P < 0.004) R2 values. The R2 values correlated well with Gd DTPA concentration (r = 0.996, P < 0.0001) and LIC (r = 0.874, P < 0.0001). A less significant relationship (r = 0.791, P < 0.0001) was found between LIC measurements and SF levels. R2 measurements appear to be significantly affected (P = 0.04) by different degrees of hepatic fibrosis. The patients' liver R2 values did not correlate with myocardial R2 values (r = 0.038, P < 0.21).

CONCLUSION

Tissue iron deposition in beta-thalassemic patients may be adequately quantified using R2 measurements obtained with a 16-echo MRI sequence with short ES (5 msec), even in patients with a relatively increased iron burden.

The prevalence of anemia in adolescents: a study from Turkey

A cross-sectional method was used to study a group of 400 high school students in Kocaeli, Turkey, aged 14 to 16 years, identified among 17,812 high school students. Students from 10 high schools were selected using a random sampling method. Whole blood counts were performed as a screening test for anemia. Serum ferritin levels and, when necessary, hemoglobin electrophoresis were determined for anemic students. Iron medication was prescribed for iron deficiency and genetic counseling was given to adolescents with thalassemia trait. Out of 338 participating students (mean age, 14.72+/-0.71 y), anemia (hemoglobin <12 g/dL for girls and <13 g/dL for boys) was detected in 17/174 girls (9.7%) and 6/164 boys (3.6%). Iron deficiency anemia was detected in 20/23 (86.9%) of anemic children [15/17 (88.2%) girls and 4/6 (66.6%) boys]. Of 23 students with anemia 2 had beta-thalassemia trait and 2 had both iron deficiency, and beta-thalassemia trait. Etiology of anemia could not be defined in 1 student. The prevalence of adolescent anemia in Kocaeli is almost equal to that in developed countries.