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Nondeletional type of hereditary persistence of fetal haemoglobin: molecular characterization of three unrelated Thai HPFH
Author(s) -
Winichagoon Pranee,
Fucharoen Suthat,
Wilairat Prapon,
Chihara Kazuo,
Fukumaki Yasuyuki
Publication year - 1994
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1994.tb06740.x
Subject(s) - biology , microbiology and biotechnology , genetics , gene cluster , gene , globin , haplotype , locus control region , locus (genetics) , restriction site , allele , restriction enzyme , promoter , gene expression
Summary The β‐globin gene clusters of three unrelated Thai families with a nondeletional type of hereditary persistence of fetal haemoglobin (HPFH) were studied using polymerase chain reaction‐related techniques. All appeared to have normal nucleotide sequences from the Cap site to position ‐400 of both the G γ‐ and A γ‐globin genes. Two individuals suspected of having a β‐thalassaemia gene linked to the high HbF condition also had a normal β‐globin gene sequence, spanning from position ‐108 from the Cap site to the polyadenylation site. Deletion of four nucleotides, AGCA, at positions ‐225 to ‐222 of one A γ‐globin allele was detected in one subject and was confirmed by dot‐blot hybridization. Restriction fragment length polymorphisms in the β‐globin gene cluster showed that the 5’ haplotype (‐ + ‐ ++) and the presence (+) of an Xmn 1 polymorphic site at ‐158 of the G γ‐globin gene are associated with the high F phenotype in these families. Direct sequencing of the 5’ hypersensitive‐2 (5’ HS‐2) site of the locus control region (LCR) showed that this Xmn , 1 (+) site is also linked to a specific rearrangement of TA repeats (TA) 9 CACATATACG(TA) 10 , in HS‐2 segment.