The prevalence of hemoglobin Tacoma in Finland detected by HbA1c capillary electrophoresis

Figures & data

Table 1. Numbers (n) and percentages of hemoglobin variants in Finland by region.

		A	B	C
Region	n	Hb Tacoma heterozygotes % (n)	Other variants % (n)	Hb variants total % (n)
South Ostrobothnia	500	2.00 (10)	0.20 (1)	2.20 (11)
Ostrobothnia	499	1.40 (7)	0.00	1.40 (7)
Pirkanmaa	496	1.01 (5)	0.00	1.01 (5)
North Ostrobothnia	500	0.80 (4)	0.00	0.80 (4)
North Savo	500	0.80 (4)	0.00	0.80 (4)
Southwest Finland	500	0.80 (4)	0.40 (2)	1.20 (6)
Uusimaa	499	0.40 (2)	0.20 (1)	0.60 (3)
Kainuu	331	0.30 (1)	0.30 (1)	0.60 (2)
North Karelia	500	0.20 (1)	0.00	0.20 (1)
Lapland	234	0.00	0.00	0.00
Satakunta	500	0.00	0.00	0.00
Total	5059	0.75 (38)	0.10 (5)	0.85 (43)

Figure 1. HbA1c electropherograms of (A) non-variant and (B) heterozygous Hb Tacoma. In (B) two very flat peaks (points 40–140 and 180–280, marked by arrows) below the normal peaks are observed and a peak characteristic of degraded hemoglobin (marked 5). HbA2 percentage is 3.4% (colored area).

Figure 2. HbA1c electropherograms of (A) the index case of homozygous Hb Tacoma, and (B) the homozygote Hb Tacoma observed among the South Ostrobothnian cohort. Non-glycated Hb Tacoma is falsely interpreted as HbA0, which shifts scale to left and misplaces HbF (at x-axis around 205, marked 4) and HbA2 (at x-axis around 260, marked 5). Peak 6 is characteristic of degraded hemoglobin. In (A) HbA1c is absent, and in (B) the corresponding area is masked by the white area (marked by arrows).

Figure 3. Hemoglobin(E) electropherograms of (A) heterozygote Hb Tacoma, and (B) homozygote Hb Tacoma. Hb Tacoma elutes at zone Z11. The amount of Hb Tacoma hemoglobin in (A) is 37%, and of HbA2 in (A) and (B) is 3.1% and 3.0%, respectively. HbH and Hb Bart are falsely suspected and are degradation products together with peaks Z13 and Z1.