Table 1

Personal particulars, phenotype and globin genotype of 18 subjects with phenotypically unexplained microcytosis

Sample number	Sex/Age	RBC (×10¹²/L)	Hb (g/dL)	MCV (fL)	MCH (pg)	Hb A₂ (%)	Hb F (%)	Hb H granules	α gap-PCR	α ARMS	α sequencing	α MLPA	β sequencing	β MLPA	δ sequencing
1	F/28	4.51	12.0	79.6	26.6	3.2	0.7	Neg	4.2 Hetero	Neg	ND	ND	N	ND	N
2	M/12	5.28	13.0	73.9	24.6	2.7	0.3	Neg	Neg	Hb CS	ND	ND	N	ND	N
3	F/39	4.89	12.0	73.1	24.5	3.0	0.3	Neg	Neg	Hb QS	ND	ND	N	ND	N
4	F/44	2.99	7.1	72.6	23.7	2.7	0.5	Neg	SEA Hetero	Neg	ND	ND	N	ND	N
5	F/42	5.09	12.0	70.9	23.6	2.5	0.4	Neg	Neg	Hb QS	ND	ND	N	ND	N
6	M/12	4.81	11.7	73.1	24.3	2.7	0.3	Neg	Neg	Neg	N	Neg	N	Neg	N
7	F/44	5.10	13.1	77.8	25.6	3.0	0.5	Neg	Neg	Hb QS	ND	ND	N	ND	N
8	F/20	4.56	11.7	78.7	25.7	2.7	0.2	Neg	Neg	Neg	N	Neg	N	Neg	N
9	M/23	5.49	14.5	78.1	26.5	2.6	0.2	Neg	Neg	Hb CS	ND	ND	N	ND	N
10	F/38	5.00	13.2	78.7	26.4	2.8	0.3	Neg	3.7 Hetero	Neg	ND	ND	N	ND	N
11	F/82	4.15	10.5	78.8	25.2	2.3	0.5	Neg	SEA Hetero	Neg	ND	ND	N	ND	N
12	M/81	5.26	13.2	79.3	25.1	3.4	0.2	Neg	Neg	Hb QS	ND	ND	N	ND	N
13	F/51	4.48	10.3	72.2	23.1	2.2	0.1	Neg	3.7 Hetero	Neg	ND	ND	N	ND	N
14	M/17	4.60	9.8	67.6	21.3	2.0	0.1	Neg	4.2 Hetero	Neg	ND	ND	N	ND	N
15	M/13	4.91	12.7	77.0	25.9	2.6	0.5	Neg	Neg	Hb CS	ND	ND	N	ND	N
16	M/8	5.56	12.8	70.5	23.0	2.9	0.3	Neg	Neg	Hb QS	ND	ND	N	ND	N
17	F/4	3.83	8.3	73.1	21.6	2.9	3.1	Neg	Neg	Neg	N	Neg	N	Neg	N
18	M/22	5.22	13.4	77.7	25.6	2.9	0.3	Neg	4.2 Hetero	Neg	ND	ND	N	ND	N

3.7, α 3.7 kb deletion; 4.2, α 4.2 kb deletion.
ARMS, amplification refractory mutation system; CS, Constant Spring; Hb, haemoglobin; Hetero, heterozygous; MCH, mean corpuscular haemoglobin concentration; MCV, mean corpuscular volume; MLPA, multiplex ligation-dependent probe amplification; N, normal; ND, not done; Neg, negative; QS, Quong Sze; RBC, red blood cell count; SEA, α South-East Asian.