IthaID: 314

We follow the HGVS sequence variant nomenclature and IUPAC standards.

Comments: This deletion is reported to span 20.5 kb on the α-globin gene cluster. According to Nicholls et al 1987 [PMID: 3032452], the 5’ and 3’ breakpoints are localised within an Alu region between the HBZ and HBZP1 genes (157285-157337) and the HBA1 gene (177005-177038), respectively. The sequencing primers by Tan et al 2001 [PMID: 11439976] place the 5’ breakpoint downstream of the HBZ gene (157041-157061) and the 3’ breakpoint upstream the HBQ1 gene (0.3 kb from the HBA1 gene) (177699-177719). The primers used by de Mare et al 2010 [PMID: 20353357] place the 3’ breakpoint closer to the HBA1 gene (177547-177576). Using the SALSA MLPA® Probemix P140-C1 HBA kit, the immediate 5' and 3' MLPA probe pairs (17214-SP0457-L20489 and 08498-L21607) are located at positions 152593-152701 (0.2 kb before HBZ) and 177167-177224 (HBA1 intron 2). As the breakpoints are not clearly defined, the deletion size shown on sequence viewer is just an approximation. Coordinates: GRCh38.p13, NC_000016.10

Heterozygous records (preview in IthaPhen)

1. Nicholls RD, Higgs DR, Clegg JB, Weatherall DJ, Alpha zero-thalassemia due to recombination between the alpha 1-globin gene and an AluI repeat., Blood, 65(6), 1434-8, 1985
2. Baysal E, Kleanthous M, Bozkurt G, Kyrri A, Kalogirou E, Angastiniotis M, Ioannou P, Huisman TH, alpha-Thalassaemia in the population of Cyprus., Br. J. Haematol. , 89(3), 496-9, 1995
3. de Mare A, Groeneger AH, Schuurman S, van den Bergh FA, Slomp J, A rapid single-tube multiplex polymerase chain reaction assay for the seven most prevalent alpha-thalassemia deletions and alphaalphaalpha(anti 3.7) alpha-globin gene triplication., Hemoglobin, 34(2), 184-90, 2010