HBA2 |
- 30
Haplo
Score - 0
Triplo
Score
Gene Facts External Data Attribution
- HGNC Symbol
- HBA2 (HGNC:4824) HGNC Entrez Ensembl OMIM UCSC GeneReviews LOVD LSDB ClinVar
- HGNC Name
- hemoglobin subunit alpha 2
- Gene type
- protein-coding gene
- Locus type
- gene with protein product
- Previous symbols
- No previous names found
- Alias symbols
- HBA-T2
- %HI
- 60.06(Read more about the DECIPHER Haploinsufficiency Index)
- pLI
- 0(Read more about gnomAD pLI score)
- LOEUF
- 1.92(Read more about gnomAD LOEUF score)
- Cytoband
- 16p13.3
- Genomic Coordinates
-
GRCh37/hg19: chr16:222875-223709 NCBI Ensembl UCSC GRCh38/hg38: chr16:172876-173710 NCBI Ensembl UCSC - MANE Select Transcript
- NM_000517.6 ENST00000251595.11 (Read more about MANE Select)
Dosage Sensitivity Summary (Gene)
Dosage ID:
ISCA-11790
ClinGen Curation ID:
CCID:007272
Curation Status:
Complete
Issue Type:
Dosage Curation -
Gene
Haploinsufficiency:
Gene Associated with Autosomal Recessive Phenotype
(30)
Triplosensitivity:
No Evidence for Triplosensitivity
(0)
Last Evaluated:
07/06/2012
Haploinsufficiency (HI) Score Details
HI Score:
30
HI Evidence Strength:
Gene Associated with Autosomal Recessive Phenotype
(Disclaimer)
HI Disease:
- alpha thalassemia Monarch
HI Evidence Comments:
Autosomal recessive type defects (including homozygous or compound heterozygous intragenic CNCs and whole gene deletions) of HBA2 cause Alpha-thalassemia.
Deletion of both α-globin genes (i.e. HBA1 and HBA2) on chromosome 16: More than 20 different deletions ranging from approximately 6 kb to more than 300 kb and removing both α-globin genes (and sometimes embryonic HBZ) have been reported. In the homozygous state these deletions result in Hb Bart syndrome. When any of these alleles occur in combination with another allele carrying a single α-globin gene deletion the result is HbH disease (GeneReviews).
Hemoglobin Bart hydrops fetalis (Hb Bart) syndrome, the most severe form of α-thalassemia, is characterized by fetal onset of generalized edema, ascites, pleural and pericardial effusions, and severe hypochromic anemia, in the absence of ABO or Rh blood group incompatibility. It is usually detected by ultrasonography at 22 to 28 weeks' gestation and can be suspected in an at-risk pregnancy at 13 to 14 weeks' gestation when increased nuchal thickness, possible placental thickness, and increased cardiothoracic ratio are present. Death in the neonatal period is almost inevitable. All four α-globin alleles are deleted or dysfunctional (inactivated).
Of note, in certain instances, carriers may display an α-thalassemia trait hematologic phenotype. Please see GeneReviews for more detailed information.
Triplosensitivity (TS) Score Details
TS Score:
0
TS Evidence Strength:
No Evidence for Triplosensitivity (Disclaimer)
TS Evidence Comments:
No literature identified.
Genomic View
Select assembly:
(NC_000016.9)
(NC_000016.10)