IthaID: 3432
Names and Sequences
| Functionality: | Neutral polymorphism | Pathogenicity: | N/A |
|---|---|---|---|
| Common Name: | Hkαα | HGVS Name: | N/A |
We follow the
HGVS sequence variant nomenclature
and
IUPAC standards.
Comments: The HKαα allele results from a complex rearrangement of the α-globin gene cluster containing both the -α3.7 [IthaID: 300] and ααα(anti 4.2) [IthaID: 2569] unequal crossover junctions on the same chromosome. The HKαα allele contains neither a single gene deletion nor triplication. It consists of two functional genes; α2 and α2/α1 (fusion) genes (See [PMID: 22989259] for a diagram illustrating the crossover that leads to the HKαα allele). Heterozygotes with the HKαα allele (HKαα/αα and βN/βN) present with normal hematological phenotype. The α-globin mRNA level of the HKαα allele heterozygotes (HKαα/αα) is similar to that of normal individuals (αα/αα). Individuals with HKαα/-α4.2 or HKαα/αWSα genotypes showed silent α-thalassemia, while individuals with the HKαα/--SEA genotype showed mild α-thalassemia. HKαα/αα and HKαα/-α3.7 combined with the HBB variant displayed obvious hematological features of β-thalassemia [PMID: 36388814]. The HKαα allele can be detected and distinguished from other co-inherited α alleles using TGS based on single-molecule real-time (SMRT) technology.
External Links
No available links
Phenotype
| Allele Phenotype: | Neutral |
|---|---|
| Associated Phenotypes: | N/A |
Location
| Chromosome: | 16 |
|---|---|
| Locus: | NG_000006.1 |
| Locus Location: | N/A |
| Size: | N/A |
| Fusion involves: | α2, α1, α3.7 hybrid |
Other details
| Type of Mutation: | Fusion |
|---|---|
| Ethnic Origin: | Chinese |
| Molecular mechanism: | N/A |
| Inheritance: | Recessive |
| DNA Sequence Determined: | Yes |
In silico pathogenicity prediction
Sequence Viewer
Publications / Origin
- Li Z, Cai S, Rong K, Song G, Li Y, Guo R, The first compound heterozygosity for HKalpha alpha allele and Southeast Asian deletion allele., Clin. Biochem., 40(0), 407-10, 2007 PubMed
- Shang X, Li Q, Cai R, Huang J, Wei X, Xu X, Molecular characterization and clinical presentation of HKαα and anti-HKαα alleles in southern Chinese subjects., Clin. Genet., 83(5), 472-6, 2013 PubMed
- Wu MY, Li J, Li SC, Li R, Liao C, Li DZ, Compound Heterozygosity for HKαα and an in Cis Deletion of Double α Genes Presents as α-Thalassemia Trait., Hemoglobin, 39(4), 256-9, 2015 PubMed
- Zhang M, Huang H, Chen M, Chen L, Wang Y, Lin N, Li Y, Chen X, Wang L, Lin Y, Xu L, [Variant analysis for patients from Fujian area with Hong Kong αα type thalassemia]., Zhonghua Yi Xue Yi Chuan Xue Za Zhi, 36(4), 297-300, 2019 PubMed
- Li J, Ye G, Zeng D, Tian B, Wang W, Feng Q, Zhu C, Accurate genotype diagnosis of Hong Kongαα thalassemia based on third-generation sequencing., Ann Transl Med, 10(20), 1113, 2022 PubMed