RT Journal Article
SR Electronic
T1 A laboratory strategy for genotyping haemoglobin H disease in the Chinese
JF Journal of Clinical Pathology
JO J Clin Pathol
FD BMJ Publishing Group Ltd and Association of Clinical Pathologists
SP 931
OP 934
DO 10.1136/jcp.2006.042242
VO 60
IS 8
A1 Amy Yuk-Yin Chan
A1 Chi-Chiu So
A1 Edmond Shiu-Kwan Ma
A1 Li-Chong Chan
YR 2007
UL http://jcp.bmj.com/content/60/8/931.abstract
AB Background: The thalassaemias are the commonest blood disorders worldwide, with South East Asia and southern China as areas of high prevalence. Accurate diagnosis of these disorders helps in clinical management with improved outcome. Methods: The α-globin genotypes of 100 Chinese patients in Hong Kong with haemoglobin H (Hb H) disease were characterised. Single-tube multiplex gap-PCR was used to detect −−SEA, −α3.7 and −α4.2, while Hb CS, Hb QS and codon 30 (ΔGAG) were identified by single-tube multiplex amplification refractory mutation system (ARMS). Automated direct nucleotide sequencing of the amplified α2- and α1-globin genes was performed to characterise other non-deletional α-thalassaemia determinants. Results: In the 100 cases studied, 99 cases had −−SEA in combination with deletional α+-thalassaemia or non-deletional α-globin gene mutation involving the α2-globin gene. In 70 cases of the deletional form, 43 cases showed the genotype of (−−SEA/−α3.7) and 27 cases of (−−SEA/−α4.2). Three of the 27 cases of (−−SEA/−α4.2) were found to have Hb Q-Thailand linked in-cis with −α4.2. The remaining 30 cases were of non-deletional form with the following genotypes: 11 cases of (−−SEA/αHbCSα), 9 cases of (−−SEA/αHbQSα), 3 cases of (−−SEA/αcd30 (ΔGAG)α), 3 cases of (−−SEA/αcd31α), 2 cases of (−−SEA/αpoly-Aα), 1 case of (−−SEA/αHbWestmeadα) and 1 case of (−−non-SEA/αHbQSα). Conclusions: Based on two rapid diagnostic tests, multiplex gap-PCR and multiplex ARMS, more than 90% of the cases were genetically characterised. This laboratory strategy should be widely applicable for genetic diagnosis of α-thalassaemia.