Characterization of two deletions that remove the entire human ζ‐α globin gene complex (—^THAI and —^FIL)

Abstract

We have fully characterized two alpha thalassaemia mutants that occur in Southeast Asia, - -THAI and - -FIL. Each mutant is due to a deletion that removes the entire zeta-alpha-globin gene complex. Localization of the 5' breakpoints described here, allows the identification of unique fragments that are specific for each of the two mutations. This information can be used to assess the frequency of these mutants in Southeast Asia and will be of value in prenatal testing for alpha thalassaemia in this area.

Hemoglobin H (Hb H) disease in Canada: Molecular diagnosis and review of 116 cases

“…In addition, some cases were investigated using probes located upstream (5␣HVR, L0, L1) or downstream (3Ј␣HVR) of the -␣ gene cluster [20][21][22]. Several of the most common two-gene cis deletions were identified using the polymerase chain reaction (PCR) [23] and deletion-specific primer sets.…”

PCR-based diagnosis of the Filipino (??FIL) and Thai (??THAI) ?-thalassemia-1 deletions

“…In particular, the Filipino (−− FIL ) and Thai (−− THAI ) deletions are relatively common among certain southeast Asian populations. These deletions, originally described by FischelGhodsian and colleagues, span approximately 30-38 kb and remove the 2-globin gene as well as both ␣-globin genes [7]. Carriers of these deletions cannot be identified using the anti-immunofluorescence assay or by Southern hybridization with the -globin gene probe.…”

Frequency of Deletional α-Thalassemia Genotypes in a Predominantly Asian-American Population

“…The LO DNA probe, 11 ' 12 which hybridizes to sequences approximately 4 kb 5' to the t^-globin RNA cap site, proved to be valuable in our population for the detection of this deletion. This allele, which has lost the entire c^-a-globin gene complex, cannot be detected in a heterozygous individual with the use of the t, and a probes alone, except by the clinically unreliable method of dosage analysis (Figs 1 and 2).…”