J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://jocmr.elmerjournals.com

Original Article

Volume 17, Number 4, April 2025, pages 231-239

Phenotypic Variability and Hematological Characterization of β⁰- and β⁺-Thalassemia Carriers: A Comparative Study

Figure 1. Hematological parameters (a: Hb; b: MCV; c: MCH) among β⁰- and β⁺-thalassemia phenotypes. Both thalassemic phenotypes have a significant (P-value < 0.0001) lower hemoglobin, MCV, and MCH compared to the control group. Hb: hemoglobin; MCH: mean corpuscular hemoglobin; MCV: mean corpuscular volume.

Figure 2. Capillary electrophoresis of Hb-A₂ level among β⁰- and β⁺-thalassemia phenotypes. Both thalassemic phenotypes have a significant (P-value < 0.0001) higher Hb-A₂ compared to the control group. Hb-A₂: hemoglobin A₂.

Figure 3. Dot plot comparing Hb, MCV, MCH, and Hb-A₂ levels among β⁰- and β⁺-thalassemia phenotypes. The dot plot visualizes the differences between the β⁰-thalassemia and β⁺-thalassemia phenotypes compared to the control group. Hb: hemoglobin; Hb-A₂: hemoglobin A₂; MCH: mean corpuscular hemoglobin; MCV: mean corpuscular volume.

**Table 1.** Patient Gender and Age Distribution With Hematological Parameters Among β⁰- and β⁺-Thalassemia Phenotypes and Control Groups
Patient gender	Age (Min - Max)	Age, median (mean ± SD)	Age < 18	Age > 18
Hb: hemoglobin; Hb-A₂: hemoglobin A₂; Hb-F: hemoglobin F; MCH: mean corpuscular hemoglobin; MCV: mean corpuscular volume.
Male, N = 69 (47.6%)	1 - 80	21.5 (20.55 ± 18.27)	27	42
Female, N = 76 (52.4%)	1 - 74	21 (22.39 ± 16.46)	28	48
Variable	β⁰-thalassemia (N = 64)	β⁺-thalassemia (N = 81)	Control group (N = 50)	P value
Hematological parameter
Hb (g/dL)	11.2 ± 0.57	12.5 ± 0.62	14.44 ± 1.29	< 0.0001
Cutoff	≤ 11.0 g/dL
MCV (fL)	64.4 ± 2.8	70.3 ± 2.4	85.96 ± 3.30	< 0.0001
Cutoff	≤ 64.0 fL
MCH (pg)	18.9 ± 1.6	22.8 ± 2.6	32.3 ± 2.57	< 0.0001
Cutoff	≤ 19.0 pg
Capillary electrophoresis of hemoglobin
Hb-A (%)	93.5 ± 0.96	89.5 ± 5.5	97.55 ± 0.35	0.074
Hb-A₂ (%)	5.06 ± 0.33	4.2 ± 0.32	2.41 ± 0.37	< 0.0001
Cutoff	≥ 5.00%
Hb-F (%)	2.1 ± 1.9	1.8 ± 1.6	0.98 ± 0.89	0.050

Table 1. Patient Gender and Age Distribution With Hematological Parameters Among β⁰- and β⁺-Thalassemia Phenotypes and Control Groups

Patient gender

Age (Min - Max)

Age, median (mean ± SD)

Age < 18

Age > 18

Hb: hemoglobin; Hb-A₂: hemoglobin A₂; Hb-F: hemoglobin F; MCH: mean corpuscular hemoglobin; MCV: mean corpuscular volume.

Male, N = 69 (47.6%)

1 - 80

21.5 (20.55 ± 18.27)

Female, N = 76 (52.4%)

1 - 74

21 (22.39 ± 16.46)

Variable

β⁰-thalassemia (N = 64)

β⁺-thalassemia (N = 81)

Control group (N = 50)

P value

Hematological parameter

Hb (g/dL)

11.2 ± 0.57

12.5 ± 0.62

14.44 ± 1.29

< 0.0001

Cutoff

≤ 11.0 g/dL

MCV (fL)

64.4 ± 2.8

70.3 ± 2.4

85.96 ± 3.30

< 0.0001

Cutoff

≤ 64.0 fL

MCH (pg)

18.9 ± 1.6

22.8 ± 2.6

32.3 ± 2.57

< 0.0001

Cutoff

≤ 19.0 pg

Capillary electrophoresis of hemoglobin

Hb-A (%)

93.5 ± 0.96

89.5 ± 5.5

97.55 ± 0.35

0.074

Hb-A₂ (%)

5.06 ± 0.33

4.2 ± 0.32

2.41 ± 0.37

< 0.0001

Cutoff

≥ 5.00%

Hb-F (%)

2.1 ± 1.9

1.8 ± 1.6

0.98 ± 0.89

0.050

**Table 2.** Population Distribution in Jordan’s Governorates
Governorate	Frequency	%
Amman	91	62.75
Irbid	23	15.86
Zarqa	14	9.66
Maan	4	2.76
Mafraq	3	2.07
Tafilah	3	2.07
Jerash	2	1.38
Madaba	2	1.38
Aqaba	2	1.38
Balqa	1	0.69

Table 2. Population Distribution in Jordan’s Governorates

Governorate

Frequency

Amman

62.75

Irbid

15.86

Zarqa

9.66

Maan

2.76

Mafraq

2.07

Tafilah

2.07

Jerash

1.38

Madaba

1.38

Aqaba

1.38

Balqa

0.69

**Table 3.** β-Thalassemia Variants and Phenotypes (β⁰ and β⁺) Distribution
Variant name	HGVS	Type of variant	Phenotype	Distribution	n	%
β⁰ phenotypes (N = 64) (44.1%)
IVS 2.1 [G>A]	HBB: c.315+1G>A	RNA processing/splice junction	β⁰	Mediterranean, US Blacks	21	32.8
IVS 1.1 [G>A]	HBB: c.92+1G>A	RNA processing/splice junction	β⁰	Mediterranean	18	28.1
Codon 8 [-AA]	HBB: c.25_26delAA	RNA translation/frameshift	β⁰	Mediterranean	8	12.5
Codon 5 [-CT]	HBB: c.17_18delCT	RNA translation/frameshift	β⁰	Mediterranean	7	10.9
Codon 39 [C>T]	HBB: c.118C>T	RNA translation/nonsense codons	β⁰	Mediterranean	7	10.9
Codon 6 [-A]	HBB: c.20delA	RNA translation/frameshift	β⁰	Mediterranean, US Blacks	1	1.6
IVS 1.130 [G>C]	HBB: c.93-1G>C	RNA processing/splice junction	β⁰	Italian, Japanese, UAE	1	1.6
Codon 44 [-C]	HBB: c.135delC	RNA translation/frameshift	β⁰	Kurdish	1	1.6
β⁺ phenotypes (N = 81) (55.9%)
IVS 1.6 [T>C]	HBB: c.92+6T>C	RNA processing/consensus splice sites	β⁺	Mediterranean	28	34.6
IVS 1.110 [G>A]	HBB: c.93-21G>A	RNA processing/cryptic splice sites	β⁺	Mediterranean	21	25.9
IVS 2.745 [C>G]	HBB: c.316-106C>G	RNA processing/cryptic splice sites	β⁺	Mediterranean	16	19.8
IVS 1.5 [G>C]	HBB: c.92+5G>C	RNA processing/consensus splice sites	β⁺	Asian Indian, SE Asian	5	6.2
-30 [T>A]	HBB: c.-80T>A	Transcriptional variants/promoter regulatory elements	β⁺	Mediterranean, Bulgarian	4	4.9
-87 [C>G]	HBB: c.-137C>G	Transcriptional variants/promoter regulatory elements	β⁺⁺	Mediterranean	3	3.7
-101 [C>T]	HBB: c.-151C>T	Transcriptional variants/promoter regulatory elements	β⁺⁺ (silent)	Mediterranean	3	3.7
IVS 2.848 [C>A]	HBB: c.316-3C>A	RNA processing/consensus splice sites	β⁺	UB Blacks, Egyptian, Iranian	1	1.2

Table 3. β-Thalassemia Variants and Phenotypes (β⁰ and β⁺) Distribution

Variant name

HGVS

Type of variant

Phenotype

Distribution

β⁰ phenotypes (N = 64) (44.1%)

IVS 2.1 [G>A]

HBB: c.315+1G>A

RNA processing/splice junction

β⁰

Mediterranean, US Blacks

32.8

IVS 1.1 [G>A]

HBB: c.92+1G>A

RNA processing/splice junction

β⁰

Mediterranean

28.1

Codon 8 [-AA]

HBB: c.25_26delAA

RNA translation/frameshift

β⁰

Mediterranean

12.5

Codon 5 [-CT]

HBB: c.17_18delCT

RNA translation/frameshift

β⁰

Mediterranean

10.9

Codon 39 [C>T]

HBB: c.118C>T

RNA translation/nonsense codons

β⁰

Mediterranean

10.9

Codon 6 [-A]

HBB: c.20delA

RNA translation/frameshift

β⁰

Mediterranean, US Blacks

1.6

IVS 1.130 [G>C]

HBB: c.93-1G>C

RNA processing/splice junction

β⁰

Italian, Japanese, UAE

1.6

Codon 44 [-C]

HBB: c.135delC

RNA translation/frameshift

β⁰

Kurdish

1.6

β⁺ phenotypes (N = 81) (55.9%)

IVS 1.6 [T>C]

HBB: c.92+6T>C

RNA processing/consensus splice sites

β⁺

Mediterranean

34.6

IVS 1.110 [G>A]

HBB: c.93-21G>A

RNA processing/cryptic splice sites

β⁺

Mediterranean

25.9

IVS 2.745 [C>G]

HBB: c.316-106C>G

RNA processing/cryptic splice sites

β⁺

Mediterranean

19.8

IVS 1.5 [G>C]

HBB: c.92+5G>C

RNA processing/consensus splice sites

β⁺

Asian Indian, SE Asian

6.2

-30 [T>A]

HBB: c.-80T>A

Transcriptional variants/promoter regulatory elements

β⁺

Mediterranean, Bulgarian

4.9

-87 [C>G]

HBB: c.-137C>G

Transcriptional variants/promoter regulatory elements

β⁺⁺

Mediterranean

3.7

-101 [C>T]

HBB: c.-151C>T

Transcriptional variants/promoter regulatory elements

β⁺⁺ (silent)

Mediterranean

3.7

IVS 2.848 [C>A]

HBB: c.316-3C>A

RNA processing/consensus splice sites

β⁺

UB Blacks, Egyptian, Iranian

1.2

**Table 4.** Distribution of Hematological Parameters and Hb Analysis Among β⁰- and β⁺⁺-Thalassemia Phenotypes
	N	Hb (g/dL)	P value	MCV (fL)	P value	MCH (pg)	P value	Hb-A (%)	P value	Hb-A₂ (%)	P value	Hb-F (%)	P value
Hb: hemoglobin; Hb-A₂: hemoglobin A₂; Hb-F: hemoglobin F; MCH: mean corpuscular hemoglobin; MCV: mean corpuscular volume.
β⁰ phenotypes
IVS 2.1 [G>A]	21	11.78 ± 1.64	< 0.0001	63.36 ± 7.59	< 0.0001	20.00 ± 1.39	< 0.0001	92.79 ± 3.75	< 0.0001	5.25 ± 0.86	< 0.0001	2.92 ± 3.98	0.0007
IVS 1.1 [G>A]	18	10.80 ± 1.42	< 0.0001	65.76 ± 5.49	< 0.0001	18.75 ± 1.36	< 0.0001	93.39 ± 3.08	< 0.0001	5.12 ± 0.89	< 0.0001	1.27 ± 2.43	0.4606
Codon 8 [-AA]	8	11.89 ± 1.26	< 0.0001	65.49 ± 4.81	< 0.0001	19.27 ± 1.68	< 0.0001	92.72 ± 3.01	< 0.0001	4.62 ± 1.38	< 0.0001	3.03 ± 3.47	0.0133
Codon 5 [-CT]	7	11.34 ± 2.58	< 0.0001	69.41 ± 7.70	< 0.0001	19.22 ± 1.97	< 0.0001	93.94 ± 1.45	0.0015	5.33 ± 0.46	< 0.0001	0.84 ± 1.69	0.9958
Codon 39 [C>T]	7	11.37 ± 1.92	< 0.0001	61.74 ± 4.56	< 0.0001	16.72 ± 1.99	< 0.0001	92.85 ± 4.88	< 0.0001	5.44 ± 0.49	< 0.0001	5.62 ± 4.21	< 0.0001
Codon 6 [-A]	1	10.10 ± 0.00	< 0.0001	63.10 ± 0.00	< 0.0001	15.98 ± 1.86	< 0.0001	94.50 ± 0.00	0.8901	5.30 ± 0.00	< 0.0001	0.00 ± 0.00	> 0.9999
IVS 1.130 [G>C]	1	11.20 ± 0.00	0.0048	60.40 ± 0.00	< 0.0001	19.96 ± 1.41	< 0.0001	92.82 ± 0.00	0.2706	4.70 ± 0.00	0.0032	3.10 ± 0.00	0.9148
Codon 44 [-C]	1	11.50 ± 0.00	< 0.0001	65.70 ± 0.00	< 0.0001	17.99 ± 1.41	< 0.0001	95.30 ± 0.00	0.9878	4.70 ± 0.00	0.0032	0.00 ± 0.00	> 0.9999
β⁺ phenotypes
IVS 1.6 [T>C]	28	12.6 ± 1.46	<0.0001	70.55 ± 7.02	< 0.0001	21.57 ± 1.39	< 0.0001	88.68 ± 4.77	< 0.0001	3.72 ± 1.38	< 0.0001	2.17 ± 4.27	0.0086
IVS 1.110 [G>A]	21	12.14 ± 1.84	<0.0001	69.01 ± 7.36	< 0.0001	21.00 ± 1.49	< 0.0001	89.67 ± 3.57	< 0.0001	4.71 ± 0.48	< 0.0001	2.31 ± 3.47	0.0122
IVS 2.745 [C>G]	16	11.63 ± 1.93	<0.0001	68.82 ± 4.99	< 0.0001	19.91 ± 1.38	< 0.0001	87.92 ± 2.35	< 0.0001	4.51 ± 0.63	< 0.0001	1.12 ± 2.00	0.6467
IVS 1.5 [G>C]	5	12.22 ± 0.53	<0.0001	67.12 ± 4.31	< 0.0001	20.00 ± 1.32	< 0.0001	90.32 ± 0.93	0.0309	3.88 ± 0.20	< 0.0001	0.76 ± 0.88	0.9993
-30 [T>A]	4	12.60 ± 0.55	0.0256	73.75 ± 5.72	< 0.0001	22.38 ± 1.29	< 0.0001	91.11 ± 3.91	< 0.0001	4.14 ± 0.57	< 0.0001	3.1 ± 5.40	0.0112
-87 [C>G]	3	13.73 ± 1.17	0.0271	73.70 ± 4.85	< 0.0001	22.39 ± 1.32	< 0.0001	89.63 ± 4.50	0.0003	4.43 ± 1.35	< 0.0001	2.67 ± 3.32	0.5068
-101 [C>T]	3	12.70 ± 1.06	0.0142	70.27 ± 8.20	< 0.0001	24.37 ± 1.51	< 0.0001	87.11 ± 7.49	< 0.0001	4.34 ± 0.17	0.0325	2.37 ± 4.08	0.1596
IVS 2.848 [C>A]	1	12.10 ± 0.00	< 0.0001	69.10 ± 0.00	< 0.0001	20.64 ± 0.58	< 0.0001	91.60 ± 0.00	0.9101	4.12 ± 0.00	0.0005	0.00 ± 0.00	> 0.9999
Control	50	14.44 ± 1.29		85.96 ± 3.30		32.31 ± 2.57		97.55 ± 0.35		2.41 ± 0.378		0.98 ± 0.89

Table 4. Distribution of Hematological Parameters and Hb Analysis Among β⁰- and β⁺⁺-Thalassemia Phenotypes

Hb (g/dL)

P value

MCV (fL)

P value

MCH (pg)

P value

Hb-A (%)

P value

Hb-A₂ (%)

P value

Hb-F (%)

P value

Hb: hemoglobin; Hb-A₂: hemoglobin A₂; Hb-F: hemoglobin F; MCH: mean corpuscular hemoglobin; MCV: mean corpuscular volume.

β⁰ phenotypes

IVS 2.1 [G>A]

11.78 ± 1.64

< 0.0001

63.36 ± 7.59

< 0.0001

20.00 ± 1.39

< 0.0001

92.79 ± 3.75

< 0.0001

5.25 ± 0.86

< 0.0001

2.92 ± 3.98

0.0007

IVS 1.1 [G>A]

10.80 ± 1.42

< 0.0001

65.76 ± 5.49

< 0.0001

18.75 ± 1.36

< 0.0001

93.39 ± 3.08

< 0.0001

5.12 ± 0.89

< 0.0001

1.27 ± 2.43

0.4606

Codon 8 [-AA]

11.89 ± 1.26

< 0.0001

65.49 ± 4.81

< 0.0001

19.27 ± 1.68

< 0.0001

92.72 ± 3.01

< 0.0001

4.62 ± 1.38

< 0.0001

3.03 ± 3.47

0.0133

Codon 5 [-CT]

11.34 ± 2.58

< 0.0001

69.41 ± 7.70

< 0.0001

19.22 ± 1.97

< 0.0001

93.94 ± 1.45

0.0015

5.33 ± 0.46

< 0.0001

0.84 ± 1.69

0.9958

Codon 39 [C>T]

11.37 ± 1.92

< 0.0001

61.74 ± 4.56

< 0.0001

16.72 ± 1.99

< 0.0001

92.85 ± 4.88

< 0.0001

5.44 ± 0.49

< 0.0001

5.62 ± 4.21

< 0.0001

Codon 6 [-A]

10.10 ± 0.00

< 0.0001

63.10 ± 0.00

< 0.0001

15.98 ± 1.86

< 0.0001

94.50 ± 0.00

0.8901

5.30 ± 0.00

< 0.0001

0.00 ± 0.00

> 0.9999

IVS 1.130 [G>C]

11.20 ± 0.00

0.0048

60.40 ± 0.00

< 0.0001

19.96 ± 1.41

< 0.0001

92.82 ± 0.00

0.2706

4.70 ± 0.00

0.0032

3.10 ± 0.00

0.9148

Codon 44 [-C]

11.50 ± 0.00

< 0.0001

65.70 ± 0.00

< 0.0001

17.99 ± 1.41

< 0.0001

95.30 ± 0.00

0.9878

4.70 ± 0.00

0.0032

0.00 ± 0.00

> 0.9999

β⁺ phenotypes

IVS 1.6 [T>C]

12.6 ± 1.46

<0.0001

70.55 ± 7.02

< 0.0001

21.57 ± 1.39

< 0.0001

88.68 ± 4.77

< 0.0001

3.72 ± 1.38

< 0.0001

2.17 ± 4.27

0.0086

IVS 1.110 [G>A]

12.14 ± 1.84

<0.0001

69.01 ± 7.36

< 0.0001

21.00 ± 1.49

< 0.0001

89.67 ± 3.57

< 0.0001

4.71 ± 0.48

< 0.0001

2.31 ± 3.47

0.0122

IVS 2.745 [C>G]

11.63 ± 1.93

<0.0001

68.82 ± 4.99

< 0.0001

19.91 ± 1.38

< 0.0001

87.92 ± 2.35

< 0.0001

4.51 ± 0.63

< 0.0001

1.12 ± 2.00

0.6467

IVS 1.5 [G>C]

12.22 ± 0.53

<0.0001

67.12 ± 4.31

< 0.0001

20.00 ± 1.32

< 0.0001

90.32 ± 0.93

0.0309

3.88 ± 0.20

< 0.0001

0.76 ± 0.88

0.9993

-30 [T>A]

12.60 ± 0.55

0.0256

73.75 ± 5.72

< 0.0001

22.38 ± 1.29

< 0.0001

91.11 ± 3.91

< 0.0001

4.14 ± 0.57

< 0.0001

3.1 ± 5.40

0.0112

-87 [C>G]

13.73 ± 1.17

0.0271

73.70 ± 4.85

< 0.0001

22.39 ± 1.32

< 0.0001

89.63 ± 4.50

0.0003

4.43 ± 1.35

< 0.0001

2.67 ± 3.32

0.5068

-101 [C>T]

12.70 ± 1.06

0.0142

70.27 ± 8.20

< 0.0001

24.37 ± 1.51

< 0.0001

87.11 ± 7.49

< 0.0001

4.34 ± 0.17

0.0325

2.37 ± 4.08

0.1596

IVS 2.848 [C>A]

12.10 ± 0.00

< 0.0001

69.10 ± 0.00

< 0.0001

20.64 ± 0.58

< 0.0001

91.60 ± 0.00

0.9101

4.12 ± 0.00

0.0005

0.00 ± 0.00

> 0.9999

Control

14.44 ± 1.29

85.96 ± 3.30

32.31 ± 2.57

97.55 ± 0.35

2.41 ± 0.378

0.98 ± 0.89