Geographical distribution of β-globin gene mutations in Syria

Figures & data

Table 1. β-thalassemia mutation frequency in Syrian population provinces are listed according to their relative geographical location.

		Region	South (490)						Coastal (214)		Middle (544)				Northwest (80)		Northeast (132)
					Damascus		Daraa/		Latakia/Tartus/								Deir ez-Zor/
		Province	Damascus		Suburb		Quneitra		Baniyas		Hama		Homs		Aleppo/Idlib		Raqqa		Total alleles
		Alleles	146		140		204		214		460		84		80		132		1460
Mutation	HUGO Nomenclature	Type	n	%	n	%	n	%	n	%	n	%	n	%	n	%	n	%	n	%
−88 [C > T]	c.-138C > T	b^+	2	1.4	9	6.4	2	1					1	1.2					14	1
−87 [C > A]	c.-137C > A	b^+			2	1.4	7	3.4											9	0.6
−86 [C > G]^a	c.-136C > G	b^+					3	1.5											3	0.2
−31 [A > G]^a	c.-81A > G	b^+									1	0.2							1	0.1
−30 [T > A]	c.-80T > A	b^+	4	2.7	15	10.7	2	1	4	2	7	1.5	2	2.4					34	2.3
−29 [A > G]^a	c.-79A > G	b^+			1	0.7					1	0.2							2	0.1
−28 [A > G]	c.-78A > G	b^+									2	0.4			1	1.3			3	0.2
5′UTR; +22 [G > A]^a	c.-29G > A	b^+									1	0.2							1	0.1
CAP  + 1 [A > C]^a	c.-50A > C	b^+	1	0.7															1	0.1
Cd 5 [-CT]	c.17-18delCT	b°	5	3.4	10	7.1	4	2	6	3	41	8.9	3	3.6	10	12.5	3	2.3	82	5.6
Codon 5/6 [−TG]^a	c.18-19delTG	b°/ b^+	1	0.7															1	0.1
Cd 8 [−AA]	c.25-26delAA	b°	2	1.4	17	12.1	11	5.4	10	5	25	5.4	13	15.5	4	5	5	3.8	87	6
Cds 8/9 [+G]	c.27-28insG	b°									4	0.9	1	1.2					5	0.3
Cd 9/10 [+T]	c.30-31insT	b°									2	0.4	2	2.4			1	0.8	5	0.3
Cd 15 [G > A]	c.47G > A	b°	3	2.1			3	1.5			4	0.9					1	0.8	11	0.8
Cds 22/23/24 [7 bp del]	c.68-74delAAGTTGG	b°							2	1									2	0.1
Codon 30 [G > C]	c.93G > C	b°									1	0.2							1	0.1
IVS-I (−3) or codon 29 [C > T]^a	c.90C > T	b^+									6	1.3							6	0.4
IVS-I.1 [G > A]	c.92 + 1G > A	b°	21	14.4	23	16.4	48	23.5	47	22	85	18.5	15	17.9	11	13.8	10	7.6	260	17.8
IVS-I.2 [T > A]^a	c.92+2T > A	b°	1	0.7															1	0.1
IVS-I.5 [G > C]	c.92 + 5G > C	b^+	4	2.7	1	0.7	1	0.5	1	0	12	2.6	2	2.4	18	22.5	21	15.9	60	4.1
IVS-I.6 [T > C]	c.92 + 6T > C	b^+	18	12.3	2	1.4	16	7.8	6	3	50	10.9	7	8.3	4	5			103	7.1
IVS-I.110 [G > A]	c.93-21G > A	b^+	36	24.7	10	7.1	49	24	81	38	101	22	12	14.3	16	20	19	14.6	324	22.2
IVS-I.116 [T > G]	c.93-15T > G	b°			2	1.4	2	1											4	0.3
IVS-I.128 [T > G]^a	c.93-3T > G	b^+													1	1.3			1	0.1
IVS-I.130 [G > C]	c.93-1G > C	b°			7	5					6	1.3			2	2.5	2	1.5	17	1.2
Cd 36/37 [−T]	c.112delT	b°									1	0.2					1	0.8	2	0.1
Cd 37 [G > A]	c.114G > A	b°					7	3.4	2	1			3	3.6					12	0.8
Cd 39 [C > T]	c.118C > T	b°	7	4.8	7	5	10	4.9	22	10	23	5	2	2.4	2	2.5	46	34.8	119	8.2
Cd 44 [−C]	c.135delC	b°			5	3.6	1	0.5	1	0	13	2.8							20	1.4
Codon 47 [+A]	c.143_144insA	b°															1	0.8	1	0.1
Codon 82/83 [−G]	c.250delG	b°															1	0.8	1	0.1
IVS-II.1 [G > A]	c.315 + 1G > A	b°	16	11	14	10	17	8.3	16	7	26	5.7	7	8.3	8	10	7	5.3	111	7.6
IVS-II.705 [T > G]^a	c.316-146T > G	b^+					1	0.5											1	0.1
IVS-II.745 [C > A]	c.316-106C > G	b^+	1	0.7			3	1.5			2	0.4	2	2.4					8	0.5
IVS-II-848 [C −> A]	c.316-3C > A	b^+															2	1.5	2	0.1
IVS-1-25 [25 bp del]	c. 93-22_95del	b°	4	2.7	3	2.1					2	0.4					1	0.8	10	0.7
290 bp deletion	c.-176_92 + 25del	b°									6	1.3							6	0.4
Unknown and others			20	13.7	12	8.6	17	8.3	16	7	38	8.3	12	14.3	3	3.8	11	8.3	129	8.8
Total number of alleles			146	100	140	100	204	100	214	100	460	100	84	100	80	100	132	100	1460	100
Total number of mutations			16		16		18		12		24		14		11		15		38

Notes: b⁺, beta-plus-thalassemia; b°, beta-zero-thalassemia; b°/⁺, beta-zero/plus-thalassemia; n, number of alleles studied. The frequency of eight common mutations in each province has been written in bold.

^aMutation found in Syria for the first time.

Figure 1. The β-globin gene mutation spectrum in thalassemia Syrian population.

Figure 2. Histogram of the relative frequencies of the eight common β-thalassemia mutations in some provinces in Syria. The eight β-globin gene mutations are as follows: IVS-I.110 [G > A], IVS-I.1 [G > A], Cd 39 [C > T], IVS-II.1 [G > A], IVS-I.6 [T > C], Cd 8 [−AA], Cd 5 [−CT] and IVS-I.5 [G > C]. The frequencies of all other mutations are summed. The number of alleles analyzed in each province is indicated in Table 1.

Figure 3. The common β-thalassemia gene mutations in different regions of Syria. NWR, Northwest region; MR, Middle region; CR, Coastal region; SR, South region; NER, Northeast region. The map of Syria was generated using the free web tool Pixel Map Generator (http://pixelmap.amcharts.com).