Interaction between Hb E and Hb Yala (HBB:c.129delT); a novel frameshift beta globin gene mutation, resulting in Hemoglobin E/β⁰ thalassemia

Figures & data

Table 1. Hematological parameters in a Thai family with a frameshift mutations at codon 42 (-T) in the β-globin gene.

Cases	Age	Hb	Hct	MCV	MCH	MCHC	RDW	Retic.	NRBC	Hapto.	Hb typing (%)			α-Globin	β-Globin	Xmn I
	(yrs)	(g/dL)	(%)	(fL)	(pg)	(g/dL)	(%)	(%)	(/100wbc)	(U/L)	A	F	A2/E	Genotypes	Genotypes	Sites
Proband	11	8.7	25.9	62.1	20.9	32.6	26.2	6	16	<10	0	60.2	39.8	αα/αα	β^YL/β^E	+/−
The mother	38	11.4	35.4	63	20.3	32.2	15.1	1	0	ND	94.9	0	5.1	αα/αα	β^YL/β	+/−

ND, not determined; MCV, mean corpuscular volume; MCH, mean cell hemoglobin; MCHC, mean cell hemoglobin concentration; NRBC, nucleated red blood cells; RDW, red cell distribution width; Retic., reticulocyte count; Hapto., haptoglobin; YL, Hb Yala.

Figure 1. Molecular identification of Hb Yala (c.129delT) in a Thai family, (A) Direct genomic sequencing reveals T-deletion (black arrow) at the codon 42 of the β-globin gene in patient (a) and her mother (b) resulting in a generation of new termination codon (TGA) at codon 60 ((c) and the lower panel). The protein sequences are shown in italic. N = normal genomic sequence; M = mutant genomic sequence. (B) Confirmation for the novel mutation using the PCR-based analysis. A schematic diagram shows the generation of a new restriction enzyme site of Sml I by codon 42 (-T) in the amplified β-globin gene fragment from both patient (P) and her mother (M). This PCR-RFLP fragment was not observed in normal controls (N₁ and N₂). U, undigested PCR products.