IthaID: 314
Names and Sequences
| Functionality: | Globin gene causative mutation | Pathogenicity: | N/A |
|---|---|---|---|
| Common Name: | -(α)20.5 | HGVS Name: | NG_000006.1:g.(18148_18200)_(37868_37901)del |
| Hb Name: | N/A | Protein Info: | N/A |
Also known as:
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
We follow the HGVS sequence variant nomenclature and IUPAC standards.
Phenotype
| Hemoglobinopathy Group: | Thalassaemia |
|---|---|
| Hemoglobinopathy Subgroup: | α-thalassaemia |
| Allele Phenotype: | α0 |
| Associated Phenotypes: | Haemolytic anaemia [HP:0001878] |
Location
| Chromosome: | 16 |
|---|---|
| Locus: | NG_000006.1 |
| Locus Location: | 18200 |
| Size: | 19.668 kb |
| Deletion involves: | α2, α1 |
Other details
| Type of Mutation: | Deletion |
|---|---|
| Ethnic Origin: | Mediterranean |
| Molecular mechanism: | N/A |
| Inheritance: | Recessive |
| DNA Breakpoint Determined: | Yes |
In silico pathogenicity prediction
Frequencies
Publications / Origin
- 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
- 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
- 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