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A new Turkish type of β‐thalassaemia major with homozygosity for two non‐consecutive 7.6 kb deletions of the Ψβ and β genes and an intact δ gene
Author(s) -
ÖNer C.,
ÖNer R.,
Guurgey A.,
Altay Ç.
Publication year - 1995
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.1365-2141.1995.tb03305.x
Subject(s) - genetics , gene , biology , turkish , thalassemia , disease gene identification , mutation , linguistics , philosophy , exome sequencing
Summary. In a 2.5‐month‐old infant with β‐thalassaemia major, DNA analysis of the gamma‐beta region revealed homozygosity for two large deletions removing the entire β and β regions including their 5’ promoter regions but leaving the delta gene intact. The downstream deletion was predicted to be 7.6 kb in length extending from a point 1.5 kb on the 3’ side of the δ‐globin gene to about 1.8 kb on the 3’ side of the β‐globin gene. The upstream deletion, which was also about 7.6 kb, extended from a point 1.5 kb on the 5’ side of the β‐globin gene to about 4.5 kb on the 3’ of the β gene. The δ‐giobin gene was intact. From the phenotypic expression of the disease it is concluded that removal of the β gene probably prevents derepression of the γ gene that has previously been observed in the absence of the promoter region of the β gene and the switch mechanism from gamma to beta gene expression may take place earlier than expected.