http://informahealthcare.com/hemISSN: 0363-0269 (print), 1532-432X (electronic)

Hemoglobin, Early Online: 1–5! 2014 Informa Healthcare USA, Inc. DOI: 10.3109/03630269.2014.912661

ORIGINAL ARTICLE

Molecular Update of b-Thalassemia Mutations in the Syrian Population:Identification of Rare b-Thalassemia Mutations

Rami A. Jarjour, Hossam Murad, Faten Moasses, and Walid Al-Achkar

Human Genetics Division, Molecular Biology and Biotechnology Department, Atomic Energy Commission of Syria (AECS), Damascus, Syria

Abstract

b-Thalassemia (b-thal) is an autosomal recessive disorder characterized by variable degrees ofanemia, bone marrow hyperplasia, splenomegaly, and complications related to the severity ofthe anemic state. The b-thalassemias result from mutations in and around the b-globin gene(HBB) located as a cluster on the short arm of chromosome 11. In Syria, b-thal is highlyprevalent. The main aim of this study was to identify the frequency of HBB mutations in 189Syrian b-thal patients and carriers of b-thal. Out of the 189 patients and carriers recruited in thisstudy, 181 patients had at least one HBB mutation and eight patients did not show anymutation. The 10 most frequent ones constituted 77.5% of all HBB mutations. These mutationsin order of frequency were: IVS-I-110 (G4A) (17.0%), IVS-I-1 (G4A) (14.7%), codon 39 (C4T)(14.4%), IVS-II-1 (G4A) (9.8%), codon 8 (–AA) (6.2%), IVS-I-6 (T4C) (5.2%), IVS-I-5 (G4C) (4.9%),codon 5 (–C) (3.2%), IVS-I-5 (G4A) (3.2%) and codon 37 (G4A) (2.2%). Another 21 mutationswere less frequent or sporadic. These results provide important tools for adapting a prenatalmolecular diagnostic test for the Syrian population.

Keywords

b-Thalassemia (b-thal), HBB, mutation, Syria

History

Received 3 December 2013Revised 6 January 2014Accepted 8 January 2014Published online 14 May 2014

Introduction

b-Thalassemia (b-thal) is an autosomal recessive disorder

characterized by a reduced production of Hb A (a2b2), which

results from the reduced synthesis of b-globin chains relative

to a-globin chains, thus causing an imbalance in globin chain

production and hence abnormal erythropoiesis (1). The

disease reaches a high frequency in the Mediterreanian

Basin, Africa, the Middle East, the Indian subcontinent and

Southeast Asia (1). The b-thalassemias result from mutations

in and around the the b-globin gene (HBB) located as a

cluster on the short arm of chromosome 11. Absence of

b-globin causes b0-thal. Reduced amounts of detectable

b-globin causes b+-thal (2). Over 812 b variants have so far

been reported to HbVar (2). The thalassemia mutations result

in a decreased rate of production or an absence of the

b-globin chain of the hemoglobin (Hb) molecule and are

associated with variable degrees of anemia, bone marrow

hyperplasia, splenomegaly, and complications related to the

severity of the anemic state.

In Syria, Hb disorders are highly prevalent. There are more

than 8000 registered transfusion-dependent patients at 13

thalassemia centers in 14 provinces (3). The number of

patients is increasing by almost 800 each year. The prevalence

of b-thal trait in Syria has not yet been established but it is

expected to be approximately 6.0% of the population, with an

estimated 779,000 carriers (4).

The molecular basis of the HBB mutations may vary from

one population to another. To date, very few studies have dealt

with the molecular characterization of b-thal in Syria (5,6).

The main aim of this study was to identify the frequency of

HBB mutations in a number of Syrian patients with b-thal

(homozygotes and compound heterozygotes) and in a number

of b-thal carriers (heterozygotes) for premarital counseling.

Patients and methods

This study was conducted at the Human Genetics Division,

Atomic Energy Commission of Syria (AECS), Damascus,

Syria. A total of 189 unrelated b-thal patients and car-

riers were referred by their physicians for HBB mutation

detection, genetic counseling and premarital counseling.

All the b-thal patients and b-thal carriers were of Syrian

Arab origin.

DNA Extraction

For all patients, blood samples were collected in

EDTA-containing tubes and DNA was isolated from frozen

blood samples using Mini kit QIAamp DNA Blood (Qiagen,

Hilden, Germany) according to the manufacturer’s

instructions.

HBB mutation analysis was performed for 32 mutations

using a reverse hybridization assay (b-Globin StripAssay�

MED 4-120, 4-130 or 4-140; ViennaLab Diagnostics GmbH,

Address correspondence to Dr. Rami A. Jarjour, Human GeneticsDivision, Molecular Biology and Biotechnology Department, AtomicEnergy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria.Tel: +963-11-213-2580. Fax: +963-11-611-2289. E-mail: ascientific@aec.org.sy

Hem

oglo

bin

Dow

nloa

ded

from

info

rmah

ealth

care

.com

by

Uni

vers

ity o

f M

aast

rich

t on

06/2

3/14

For

pers

onal

use

onl

y.

Vienna, Austria) according to the manufacturer’s instructions.

When the reverse hybridization assay did not detect any

mutation in a thalassemia carrier or patient, or detected one

mutation in a thalassemia patient, sequencing was performed

on an ABI PRISM� 310 Genetic Analyzer (Applied

Biosystems, Foster City, CA, USA) using the BigDye�

Terminator v3.1 Cycle Sequencing Kit and conditions

suggested by the manufacturer. Two polymerase chain

reactions (PCRs) were performed. The first reaction

amplified 146 bp of the 50 untranslated region (50UTR), the

whole exon 1, intron 1 and exon 2, and 117 bp of the intron 2

region neighboring exon 2. The second reaction amplified

234 bp of the intron 2 region neighboring exon 3, the whole

exon 3 and 302 bp of the 30UTR (7). This analysis

fully sequenced the entire HBB gene but omitted a seg-

ment of 499 bp of intron 2 in between the two reactions,

which does not frequently contain HBB mutations (HbVar

database) (2).

Every patient was informed about the study and a

written consent was signed either by the patient or his/

her parent or guardian for blood sampling. This study has

been approved by the Institutional Review Board of the

AECS.

Results

Out of the 189 patients recruited for this study, 181 patients

had at least one HBB mutation and eight patients did not carry

any mutation (Table 1). The parents of 88 (49.0%) patients

proved to be consanguineous, the parents of 76 (42.0%) were

not consanguineous and no data were available for 17 (9.0%)

cases (Table 2).

A total of 31 different HBB mutations were identified in a

cohort of 181 thalassemia patients and carriers (Table 3). The

10 most frequent ones constituted 77.5% of all the HBB

mutations found. These mutations in order of frequency were:

IVS-I-110 (G4A) (17%), IVS-I-1 (G4A) (14.7%), codon 39

(C4T) (14.4%), IVS-II-1 (G4A) (9.8%), codon 8 (–AA)

(6.2%), IVS-I-6 (T4C) (5.2%), IVS-I-5 (G4C) (4.9%),

codon 5 (–C) (3.2%), IVS-I-5 (G4A) (3.2%) and codon 37

(G4A) (2.2%); another 21 mutations were less frequent or

sporadic (Table 3).

Different genotypes were identified in the 181 patients

(Table 1). There were 94 (52.0%) homozygous patients, 30

(17.0%) were compound heterozygotes and 57 (31.0%) were

heterozygotes. The most frequent mutations among the

homozygous patients were IVS-I-110, codon 39 and IVS-I-

1, while IVS-I-1 was the most common mutation among

heterozygous patients/carriers.

Table 1. Genotypes of 189 Syrian patients with b-thalassemia:homozygotes, compound heterozygotes and heterozygotes.

n Genotype n (%)

Homozygotes1 IVS-I-110(G4A)/IVS-I-110(G4A) 212 codon 39(C4T)/codon 39(C4T) 173 IVS-I-1(G4A)/IVS-I-1(G4A) 114 IVS-II-1(G4A)/IVS-II-1(G4A) 95 codon 8(–AA)/codon 8(–AA) 86 IVS-I-6(T4C)/IVS-I-6(T4C) 57 codon 5(–CT)/codon 5(–CT) 48 IVS-I-5(G4C)/IVS-I-5(G4C) 49 IVS-I-5(G4A)/IVS-I-5(G4A) 3

10 codon 37(G4A)/codon 37(G4A) 311 IVS-I-116(T4G)/IVS-I-116(T4G) 212 codon 44(–C)/codon 44(–C) 213 �30(T4A)/�30(T4A) 214 �87(C4G)/�87(C4G) 115 �88(C4T)/�88(C4T) 116 IVS-II-848(C4A)/IVS-II-848(C4A) 1subtotal 94 (52.0)

Compound Heterozygotes17 IVS-I-5(G4A)/IVS-I-1(G4A) 318 IVS-I-1(G4A)/IVS-II-1(G4A) 219 IVS-II-1(G4A)/codon 39(C4T) 220 IVS-I-6(T4C)/IVS-II-1(G4A) 221 IVS-I-6(T4C)/IVS-I-110(G4A) 222 IVS-I-5(G4A)/codon 39(C4T) 123 IVS-I-5(G4A)/IVS-II-1(G4A) 124 IVS-I-1(G4A)/IVS-I (�1)(G4A)

or codon 30(G4C)1

25 IVS-II-745(C4G)codon 5(–CT) 126 IVS-I-1(G4A)/IVS-I-110(G4A) 127 IVS-I-1(G4A)/codon 8(–AA) 128 IVS-I-1(G4A)/exon 3 deletiona 129 IVS-II-1(G4A)/codon 5(–CT) 130 IVS-II-1(G4A)/IVS-I-110(G4A) 131 IVS-I-5(G4C)/IVS-I-110(G4A) 132 �88(C4T)/codon 37(G4A) 133 �88(C4T)/codons 36/37(–T) 134 �87(C4G)/IVS-I-1(G4A) 135 �87(C4A)/IVS-I-110(G4A) 136 IVS-I-130(G4C)/codon 44(–C) 137 codon 39(C4T)/IVS-II-745(C4G) 138 codon 39(C4T)/IVS-II-1(G4A) 139 codon 15(G4A)/codon 8(–AA) 140 codon 15(G4A)/IVS-I-110(G4A) 1subtotal 30 (16.5)

Heterozygotes41 IVS-I-1(G4A) 1142 codon 5(–CT) 543 codon 39(C4T) 544 IVS-I-5(G4C) 545 IVS-II-1(G4A) 446 IVS-II-745(C4G) 347 IVS-I-110(G4A) 348 �30(T4A) 249 IVS-I-6(T4C) 250 �101(C4T) 251 IVS-I-130(G4C) 252 IVS-1, 25 bp deletion 253 codons 36/37(–T) 154 codons 8/9(+G) 155 codon 22 (7 bp deletion) 156 codon 8(–AA) 157 �87(C4G) 158 exon 3 deletiona 159 codon 47(+A) 160 codon 15(G4A) 161 +20(C4T) (50UTR) 1

(continued )

Table 1. Continued

n Genotype n (%)

62 codons 9/10(+T) 163 codons 82/83(–G) 1subtotal 57 (31.5)

Total number of patients with b-thal mutations 181 (100.0)Patients without any b-thal mutations 8Total number of patients studied 189

aThe breakpoint of this deletion could not be characterized.

2 R. A. Jarjour et al. Hemoglobin, Early Online: 1–5

Hem

oglo

bin

Dow

nloa

ded

from

info

rmah

ealth

care

.com

by

Uni

vers

ity o

f M

aast

rich

t on

06/2

3/14

For

pers

onal

use

onl

y.

Discussion

Syria is a country in the Middle East, along the eastern shore

of the Mediterranean Sea. Ancient Syria was occupied

successively by Sumerians, Egyptians, Hittites, Assyrians,

Babylonians, Greeks, Persians and Romans. Moreover,

modern Syria was conquered by the Byzantines,

Arab Muslims, Mongols and Ottomans. Syria is very

diverse, ethnically and religiously, but most Syrians are

ethnic Arabs.

To the best of our knowledge, this is the most compre-

hensive study of b-thal in Syria. Our cohort of patients

included 189 patients and carriers. Moreover, we analyzed the

HBB mutations using a reverse hybridization assay and DNA

sequencing. Two previous studies have been published on

b-thal in Syria. In the first published study (5), 36 patients

were included and 14 HBB mutations were identified using

the amplification refractory mutation system (ARMS) and

confirmed by dot-blot analysis. The second study (6) included

82 patients and 10 HBB mutations were detected by ARMS

and RFLP (restriction fragment length polymorphism). The

samples that did not reveal any mutation by the ARMS and

restriction enzyme analysis approaches were then subjected to

denaturing gradient gel electrophoresis (DGGE) (6). It should

be noted that IVS-I-110 and IVS-I-1 are the most common

mutations in this study and the previous studies.

In this study, the frequency of 31 HBB mutations is

described in 189 unrelated Syrian patients suffering from

b-thal or carriers of b-thal. The heterogeneity of the Syrian

population is reflected in the wide range of HBB mutations.

Most of the mutations were of Mediterranean origin, while

some mutations were of Turkish, Kurdish, Egyptian, Asian

Table 3. The distribution of the 31 HBB mutations screened in Syrian patients with b-thalassemia.

Mutation Type Origin n (%)Syria(%)

Syrian (%)

Syria(%)

Lebanon(%)

Jordan(%)

Gazastrip (%)

Reference this study 6 5 2 8 9 10IVS-I-110 (G4A) b+ East Mediterranean 52 (15.7) 24.1 16 (44.0) 24.0 33.0 22.0 37.5IVS-I-1 (G4A) b0 Mediterranean 45 (13.5) 17.0 6 (16.6) 17.0 16.0 6.6 20.0codon 39 (C4T) b0 West Mediterranean 44 (13.3) 6.4 4 (11.1) 6.4 0.5 2.0 11.5IVS-II-1 (G4A) b0 Mediterranean 30 (9.1) 4.2 1 (2.8) 4.0 10.0 19.8 1.0codon 8 (–AA) b0 Turkish 19 (5.7) 0.7 – 0.7 2.5 – –IVS-I-6 (T4C) b+ West Mediterranean 16 (4.8) – – 4.0 15.0 6.6 7.5IVS-I-5 (G4C) b+ Asian Indian 15 (4.5) – – – 0.5 5.5 –codon 5 (–CT) b0 Mediterrranean 15 (4.5) – – 8.5 4.0 3.3 10.0IVS-I-5 (G4A) b+ Algerian 10 (3.0) – – – – – –codon 37 (G4A) b0 Saudi, Egyptian 7 (2.1) – – 1.4 – 8.8 1.0�30 (T4A) b+ Turkish 6 (1.8) 7.1 – 7.0 0.5 – –codon 44 (–C) b0 Kurdish 5 (1.5) – – – 1.0 – –IVS-II-745 (C4G) b+ Mediterranean 5 (1.5) 1.4 6 (16.6) 1.4 1.0 12.0 –�87 (C4G) b+ Mediterranean 4 (1.2) 2.1 – 2.0 1.5 2.0 –�88 (C4T) b+ Asian Indian 4 (1.2) – – 2.0 1.5 – –IVS-I-116 (T4G) b0 Mediterranean 4 (1.2) – – 1.4 – – –IVS-I-130 (G4C) b0 Japanese 3 (0.9) 0.7 – – – – –codon 15 (G4A) b0 Asian Indian 3 (0.9) – – 3.5 – – –�101 (C4T) b+ Turkish 2 (0.6) – – – – – –codons 36/37 (–T) b0 Kurdish, Iranian 2 (0.6) – – – – – –IVS-II-848 (C4A) b+ Egyptian 2 (0.6) – – – – 2.0 –IVS-I, 25 bp deletion b0 Asian Indian 2 (0.6) – – – 1.0 – –exon 3 deletiona NDb NDb 2 (0.6) – – – – – –codons 8/9 (+G) b0 Asian Indian 1 (0.3) 1.4 – – 0.5 – –codon 22 (7 bp deletion) b0 Turkish 1 (0.3) – – – – – –IVS-I (�1)(G4C) or codon 30 (G4C) b0 Bulgarian 1 (0.3) – – – – – –codon 47 (+A) b0 Surinamese 1 (0.3) – – – – – –+20 (C4T) 50UTR c Mediterranean 1 (0.3) – – – – – –codons 9/10 (+T) b0 Greek 1 (0.3) – – – – – –codons 82/83 b0 Azerbaijani 1 (0.3) – – – – – –�87 (C4A) b+ Argentinean 1 (0.3) – – – – – –unknown 26 (7.8)c – – – – – –Total 331 (100.0)d 100.0 36 (100.0)

ND: not determined.aThe breakpoint of this deletion could not be characterized.bThis mutation is an innocuous single nucleotide polymorphism (SNP) associated with the IVS-II-745 mutation in cis (29).cThis is the sum of 10 and 16 because one mutation only was identified in 10 patients (10 alleles) and no mutation was identified in eight patients

(16 alleles).dThe total number of alleles is not 378 (189 patients� 2) because of the presence of one mutation in a total of 47 carriers.

Table 2. Frequency of consanguinity between parents of b-thalassemiapatients in this study.

Consanguineous

Parents (%)

Non

Consanguineous

Parents (%)

No Data

Available

(%) Total (%)

Homozygotes 60 (64.0) 28 (30.0) 6 (6.0) 94 (100.0)

Heterozygotes 20 (35.0) 29 (51.0) 8 (14.0) 57 (100.0)

Compound

heterozygotes

8 (27.0) 19 (63.0) 3 (10.0) 30 (100.0)

Total number

of patients

88 (49.0) 76 (42.0) 17 (9.0) 181 (100.0)

DOI: 10.3109/03630269.2014.912661 Frequency of �-Thalassemia Mutations in Syria 3

Hem

oglo

bin

Dow

nloa

ded

from

info

rmah

ealth

care

.com

by

Uni

vers

ity o

f M

aast

rich

t on

06/2

3/14

For

pers

onal

use

onl

y.

Indian, Greek and Azerbaijani origins. The Mediterranean

mutations [IVS-I-110, IVS-I-1, codon 39, IVS-II-1, codon 8,

IVS-I-6, IVS-I-5 (G4C), codon 5, IVS-I-5 (G4A), �30

(T4A), IVS-II-745 (C4G), �87 (C4G), and IVS-I-116

(T4G)] accounted for 81.5% of the mutations, while the

Asian Indian mutations [IVS-I-5 (G4C), �88 (C4T), codon

15 (G4A), IVS-I, 25 bp deletion, codons 8/9 (+G) and codon

47 (+A)] accounted for 8.3% of the rest of the mutations.

These findings (the high frequency of Mediterranean muta-

tions and the low frequency of Asian Indian mutations) are

similar to the findings obtained in the surrounding countries,

especially Lebanon (8), Jordan (9), the Gaza Strip (10) and

Iraq (11).

Although we noted a considerable heterogeneity of b-thal

mutations in Syria, we also estimate that more mutations

could potentially be present in the population. We could not

detect any b-thal mutation in eight patients using sequencing.

Sequencing the other parts of the HBB gene may help us

reveal the causative mutations in those patients.

Most of the mutations detected in this study can also be

found with varying frequencies in neighboring countries

(e.g. Lebanon, Jordan, Palestine and Iraq). This is in line with

studies in other parts of the world which have shown that gene

flow due to population migration is common. Moreover, most

of the patients in Syria and the neighboring countries are of

Arab origin. The most common mutations are IVS-I-110

(17.0%) and IVS-I-1 (14.7%). As for the IVS-I-110 mutation,

it has previously been shown that its frequency in Syria ranges

from 24.0 to 44.0% (5,6). However, this mutation was

overestimated in the previous studies compared with this

one. The IVS-I-110 mutant allele is frequent in Lebanon

(62.0%) (12), Egypt (57.0%) (13) Greece (42.0%) (14) and

Turkey (44.0%) (15). This mutation, which is believed to have

arisen in Turkey, is the most common mutation in the eastern

Mediterranean. This mutation has its highest frequency in

Cyprus, but its frequency gradually decreases in countries

further to the east, with a distribution pattern almost opposite

to that of IVS-II-1 (16). It has a high frequency in all

Mediterranean Arab countries (12.0–38.0%), but reaches

lower frequencies in countries around the Gulf (0.0–2.0%)

(8). However, the IVS-I-110 mutation is under represented in

the western part of the Mediterranean Basin, such as Spain

(8.5%) (17), Portugal (10.0%) (18) and is nearly absent in

Algeria (19), Tunisia (20) and Morocco (21).

The frequency of IVS-I-1 in this study was 14.7%, which is

slightly lower than what it has been previously reported to be

in Syria (17.0%) (5,6). The IVS-I-1 (Mediterranean b+)

mutation also has a high frequency on the Gaza strip (20.0%)

(22) and in Lebanon (15.0%) (12) with lower frequencies in

Gulf countries (1.0% in Oman and 3.0% in Bahrain) (8).

Codon 39 is the third most common mutation in our

studied cohort. The codon 39 (Mediterranean b0) mutation,

which is believed to be of Roman origin, is most common in

the Western Mediterranean Arab countries [27.0% in both

Tunisia (20) and Algeria (19)] and decreases towards the east

(8). However, this mutation also reaches a high frequency in

some countries of the Arabian Peninsula: 20.0% in Saudi

Arabia (23,24) and 24.0% in Bahrain (25).

IVS-II-1 is the most common mutation in northern

Iraq (Dahouk and Irbil) (26) and in Iran (34.0%) (27).

This mutation is also most common in Kuwait at a frequency

of 29.0% (28) and in the Eastern Province of Saudi Arabia

(27.0%) (24). IVS-II-1 was detected in all Arab countries

except Tunisia and Algeria, has a high frequency in North

Jordan (20.0%) and in Kuwait (29.0%) (8).

To the best of our knowledge, this is the first report that has

detected rare mutations such as codon 15, �101 (C4T),

codons 36/37 (–T), IVS-II-848 (C4A), IVS-I, 25 bp deletion,

codon 22 (7 bp deletion), IVS-I (�1) (G4A), codon 47, +20

(C4T) in the 50UTR (29), codons 9/10 (+T), codons 82/83

(–G) and �87 in the Syrian patients (Table 1).

There is a high consanguinity rate (49.0%) among the

parents of b-thal patients in this study cohort. Because of the

high consanguinity marriages, the homozygote frequency is

high in this study (64.0%) and the rate of IVS-I-110, IVS-I-1

and codon 39 homozygous mutations is high. The total rate of

consanguinity in Syria was found to be 35.4% (30). This

reflects that almost half of the marriages occur between

relatives. Public awareness of consanguineous marriage

should be increased via the mass media. Moreover, commu-

nity programs for premarital screening to detect carriers of

hemoglobinopathies such as thalassemia and sickle cell

anemia should be initiated. Premarital screening, aimed at

identifying carriers of Hb disorders, has recently been

established by the Syrian Medical Association and the

Ministry of Health.

In conclusion, this study identified a wider spectrum of

HBB mutations in Syrian patients compared to previously

published studies. These results provide important tools for

adapting a prenatal molecular diagnostic test for the Syrian

population. Despite efforts to develop gene therapy or bone

marrow transplantation, prenatal diagnosis followed by

termination of the affected fetus still remains the best form

of management at the present time.

Acknowledgements

We would like to thank Professor Ibrahim Othman, the

Director General of AECS, Damascus, Syria, and Dr. Nizar

MirAli, Head of Department, Damascus, Syria for their

support.

Declaration of interest

This project was financially supported by Atomic Energy

Commission of Syria (AECS). The authors report no conflicts

of interest. The authors alone are responsible for the content

and writing of this article.

References

1. Weatherall DJ, Clegg JB. The Thalassaemia Syndromes, 3rd ed.Oxford: Blackwell Scientific Publications, 1981.

2. Patrinos GP, Giardine B, Riemer C, et al. Improvements in theHbVar database of human hemoglobin variants and thalassemiamutations for population and sequence variation studies. NucleicAcids Res. 2004;32(Database issue):D537–D541 (http://globin.bx.psu.edu/hbvar/menu.html).

3. Al-Zir KN. Prevention of hemoglobinopathies in Syria.Hemoglobin. 2009;33(Suppl 1):S25–S27.

4. World Health Organization (WHO). Guidelines for the control ofhaemoglobin disorders. 1994.

4 R. A. Jarjour et al. Hemoglobin, Early Online: 1–5

Hem

oglo

bin

Dow

nloa

ded

from

info

rmah

ealth

care

.com

by

Uni

vers

ity o

f M

aast

rich

t on

06/2

3/14

For

pers

onal

use

onl

y.

5. el-Hazmi MA, Warsy AS, al-Swailem AR. The frequency of 14b-thalassemia mutations in the Arab populations. Hemoglobin.1995;19(6):353–360.

6. Kyriacou K, Al Quobaili F, Pavlou E, et al. Molecular character-ization of b-thalassemia in Syria. Hemoglobin. 2000;24(1):1–13.

7. Sirdah MM, Sievertsen J, Al-Yazji MS, et al. The spectrum ofb-thalassemia mutations in Gaza Strip, Palestine. Blood Cells MolDis. 2013;50(4):247–251.

8. Zahed L. The spectrum of b-thalassemia mutations in the Arabpopulations. J Biomed Biotechnol. 2001;1(3):129–132.

9. Sadiq MFG, Huisman THJ. Molecular characterization of b-thal-assemia in North Jordan. Hemoglobin. 1994;18(4–5):325–332.

10. Filon D, Oron V, Shawa R, et al. Spectrum of b-thalassemiamutations in the Gaza area. Hum Mutat. 1995;5(4):351–353.

11. Omer WA. Molecular characterization of b-thalassemia mutationsin Baghdad. Iraqi J Comm Med. 2010;23(2):90–95.

12. Zahed L, Qatanani M, Nabulsi M, et al. b-Thalassemia mutationsand haplotype analysis in Lebanon. Hemoglobin. 2000;24(4):269–276.

13. Jiffri EH, Bogari N, Zidan KH, et al. Molecular updating ofb-thalassemia mutations in the Upper Egyptian population.Hemoglobin. 2010;34(6):538–547.

14. Patrinos GP, van Baal S, Petersen MB, et al. Hellenic nationalmutation database: A prototype database for mutations leading toinherited disorders in the Hellenic population. Hum Mutat. 2005;25(4):327–333.

15. Keser I, Sanlioglu AD, Manguoglu E, et al. Molecular analysis ofb-thalassemia and sickle cell anemia in Antalya. Acta Haematol.2004;111(4):205–210.

16. Cao A, Gossens M, Pirastu M. b Thalassaemia mutations inMediterranean populations. Br J Haematol. 1989;71(3):309–312.

17. Amselem S, Nunes V, Vidaud M, et al. Determination of thespectrum of b-thalassemia genes in Spain by use of dot-blotanalysis of amplified b-globin DNA. Am J Hum Genet. 1988;43(1):95–100.

18. Morgado A, Picanco I, Gomes S, et al. Mutational spectrum ofd-globin gene in the Portuguese population. Eur J Haematol. 2007;79(5):422–428.

19. Bouhass R, Perrin P, Trabuchet G. The spectrum of b-thalassemiamutations in the Oran region of Algeria. Hemoglobin. 1994;18(3):211–219.

20. Chibani J, Vidaud M, Duquesnoy P, et al. The peculiar spectrumof b-thalassemia genes in Tunisia. Hum Genet. 1988;78(2):190–192.

21. Lemsaddek W, Picanco I, Seuanes F, et al. Spectrum of bthalassemia mutations and HbF levels in the heterozygousMoroccan population. Am J Hematol. 2003;73(3):161–168.

22. Filon D, Faerman M, Smith P, et al. Sequence analysis reveals ab-thalassaemia mutation in the DNA of skeletal remains from thearchaeological site of Akhziv, Israel. Nat Genet. 1995;9(4):365–368.

23. el-Hazmi MA, Warsy AS. Appraisal of sickle-cell and thalassaemiagenes in Saudi Arabia. East Mediterr Health J. 1999;5(6):1147–1153.

24. Al-Ali AK, Al-Ateeq S, Imamwerdi BW, et al. Molecular bases ofb-thalassemia in the Eastern Province of Saudi Arabia. J BiomedBiotechnol. 2005;2005(4):322–325.

25. Jassim N, Merghoub T, Pascaud O, et al. Molecular basis ofb-thalassemia in Bahrain: An epicenter for a Middle East specificmutation. Ann N Y Acad Sci. 1998;850:407–409.

26. Al-Allawi NA, Hassan KM, Sheikha AK, et al. b-Thalassemiamutations among transfusion-dependent thalassemia major patientsin Northern Iraq. Mol Biol Int. 2010;2010:1–4.

27. Najmabadi H, Karimi-Nejad R, Sahebjam S, et al. The b-thalas-semia mutation spectrum in the Iranian population. Hemoglobin.2001;25(3):285–296.

28. Adekile AD, Gu L-H, Baysal E, et al. Molecular characterizationof a-thalassemia determinants, b-thalassemia alleles, and bS

haplotypes among Kuwaiti Arabs. Acta Haematol. 1994;92(4):176–181.

29. Ropero P, Gonzalez FA, Cela E, et al. Association in cis ofthe mutations +20 (C4T) in the 50 untranslated region andIVS-II-745 (C4G) on the b-globin gene. Hemoglobin. 2013;37(2):112–118.

30. Othman H, Saadat M. Prevalence of consanguineous marriagesin Syria. J Biosoc Sci. 2009;41(5):685–692.

DOI: 10.3109/03630269.2014.912661 Frequency of �-Thalassemia Mutations in Syria 5

Hem

oglo

bin

Dow

nloa

ded

from

info

rmah

ealth

care

.com

by

Uni

vers

ity o

f M

aast

rich

t on

06/2

3/14

For

pers

onal

use

onl

y.