Screening of Some Indicators for Alpha-Thalassemia in Fujian Province of Southern China

Figures & data

Table 1 Genotypes Identified Among Alpha-Thalassemia Carriers

Genotype	Subjects (n)	Frequency (%)
–^SEA/αα	1699	63.9
-α^3.7/αα	582	21.9
-α^4.2/αα	152	5.7
α^QSα/αα	67	2.5
α ^csα/αα	51	1.9
–^THAI/αα	34	1.3
α ^wsα/αα	32	1.2
–^SEA/-α^3.7	16	0.6
–^SEA/-α^4.2	7	0.3
-α^3.7/-α^3.7	4	0.2
-α^3.7/α^QSα	4	0.2
–^SEA/α^wsα	2	0.08
-α^3.7/-α^4.2	2	0.08
-α^4.2/-α^4.2	1	0.04
-α^3.7/α ^wsα	1	0.04
–^SEA/α ^csα	1	0.04
–^SEA/HKαα	1	0.04
-α^3.7/α ^csα	1	0.04
α^QSα/α^QSα	1	0.04
Total	2658	100

Abbreviations: SEA, Southeast Asian deletion; HK, HongKong deletion; THAI, Thailand deletion; CS, Hb Constant Spring; QS, Hb Quong Sze; WS, Hb Westmead.

Figure 1 Histogram showing number of alpha-thalassemia carriers and negative-for-alpha-thalassemia participants with MCV, MCH and HbA₂. Dash lines indicate the cutoff MCV of 80fL, MCH of 27pg and HbA₂ of 2.5% used for screening of alpha-thalassemia. The proportions of cases found at below and above these cutoff levels are provided.

Table 2 Hematological Values for Each Genotype and the Difference Between Groups

Indices/Mutation Unit/(Number)	–^SEA/αα (a) (1699)	-α^3.7/αα (b) (582)	-α^4.2/αα (c) (152)	α^QSα/αα (d) (67)	α^csα/αα (e) (51)	–^THAI/αα (f) (34)	α^wsα/αα (g) (32)	p
MCV fL	68.40 (66.00,70.90)	81.15 (78.70,84.30)	81.30 (78.90,84.00)	75.00 (72.50,79.00)	81.20 (78.40,83.30)	67.10 (61.90,68.70)	80.80 (79.10,82.10)	<0.05
MCH pg	21.40 (20.80,22.10)	26.75 (26.00,27.70)	26.70 (26.00,27.80)	24.20 (23.40,24.90)	26.60 (25.90,27.40)	21.45 (20.80,21.90)	27.30 (26.65,28.60)	<0.05
HbA2%	2.30 (2.20,2.40)	2.50 (2.40,2.70)	2.50 (2.35,2.65)	2.60 (2.40,2.70)	2.20 (2.10,2.30)	2.40 (2.30,2.50)	2.70 (2.55,2.90)	<0.05

Notes: The distribution of indicators is described in the way of median (quartile). The total number of studied individuals is indicated in parenthesis under mutations’ names. The parameters were compared between groups using the Kruskal–Wallis test.

Table 3 Detection Rates of the Different Screening Schemes

Genotype		Detection Rate
	(MCV/MCH)	(HbA2)	(MCV/MCH/HbA2)
–^SEA/αα	99.2 (1685/1699)	81.9 (1391/1699)	99.8 (1695/1699)
-α^3.7/αα	62.5 (364/582)	36.6 (213/582)	76.3 (444/582)
-α^4.2/αα	63.2 (96/152)	36.8 (56/152)	74.3 (113/152)
α^QSα/αα	98.5 (66/67)	26.9 (18/67)	100 (67/67)
α ^csα/αα	70.6 (36/51)	90.2 (46/51)	96.1 (49/51)
–^THAI/αα	100 (34/34)	61.8 (21/34)	100 (34/34)
α ^wsα/αα	50.0 (16/32)	9.4 (3/32)	53.1 (17/32)
–^SEA/-α^3.7	100 (16/16)	100 (16/16)	100 (16/16)
–^SEA/-α^4.2	100 (7/7)	85.7 (6/7)	100 (7/7)
-α^3.7/-α^3.7	100 (4/4)	0 (0/4)	100 (4/4)
-α^3.7/α^QSα	100 (4/4)	50 (2/4)	100 (4/4)
–^SEA/α^wsα	100 (2/2)	100 (2/2)	100 (2/2)
-α^3.7/-α^4.2	100 (2/2)	50 (1/2)	100 (2/2)
-α^4.2/-α^4.2	100 (1/1)	0 (0/1)	100 (1/1)
-α^3.7/α ^wsα	100 (1/1)	0 (0/1)	100 (1/1)
–^SEA/α ^csα	100 (1/1)	100 (1/1)	100 (1/1)
–^SEA/HKαα	100 (1/1)	100 (1/1)	100 (1/1)
-α^3.7/α ^csα	100 (1/1)	100 (1/1)	100 (1/1)
α^QSα/α^QSα	100 (1/1)	0 (0/1)	100 (1/1)
Total	88.0 (2338/2658)	66.9 (1778/2658)	92.6 (2460/2658)

Note: Detection rates represent the proportion of positive cases by the three screening schemes in each genotype of the alpha-thalassemia group, respectively.