IthaID: 628
Names and Sequences
| Functionality: | Globin gene causative mutation | Pathogenicity: | Pathogenic / Likely Pathogenic |
|---|---|---|---|
| Common Name: | CD 79 GCG>GGG [Ala>Gly] | HGVS Name: | HBA2:c.239C>G |
| Hb Name: | Hb J-Singapore | Protein Info: | α2 79(EF8) Ala>Gly |
Context nucleotide sequence:
GTGCAGGTCGCTCAGGGCGGACAGC [C/G] CGTTGGGCATGTCGTCCACGTGCGC (Strand: -)
Protein sequence:
MVLSPADKTNVKAAWGKVGAHAGEYGAEALERMFLSFPTTKTYFPHFDLSHGSAQVKGHGKKVADALTNAVAHVDDMPNGLSALSDLHAHKLRVDPVNFKLLSHCLLVTLAAHLPAEFTPAVHASLDKFLASVSTVLTSKYR
Also known as:
Comments: Rare, fast moving variant comprising two amino acid substitutions; asparagine to aspartic acid at position α78 (α78(EF7)Asn>Asp) and alanine to glycine at position α79 (α79(EF8)Ala>Gly). The absence of DNA evidence for the α78 (Asn>Asp) substitution means that the deamidation happens at the protein level. On CE electrophoregram, Hb J-Singapore presents in the same migration time of Hb J-Buda and Hb Bart’s (γ4). The HPLC patterns of Hb J-Singapore and Hb J-Buda are similar. Initially reported in a Malaysian family (n 4) living in Singapore [PMID: 5085670], as well as in a Thai pregnant woman during antenatal screening [J Med Assoc Thai 2018; 101 (2): 275-8]; heterozygotes are asymptomatic.
We follow the HGVS sequence variant nomenclature and IUPAC standards.
Phenotype
| Hemoglobinopathy Group: | Structural Haemoglobinopathy |
|---|---|
| Hemoglobinopathy Subgroup: | α-chain variant |
| Allele Phenotype: | N/A |
| Stability: | N/A |
| Oxygen Affinity: | N/A |
| Associated Phenotypes: | N/A |
Location
| Chromosome: | 16 |
|---|---|
| Locus: | NG_000006.1 |
| Locus Location: | 34131 |
| Size: | 1 bp |
| Located at: | α2 |
| Specific Location: | Exon 2 |
Other details
| Type of Mutation: | Point-Mutation(Substitution) |
|---|---|
| Effect on Gene/Protein Function: | Missense codons (Protein Structure) |
| Ethnic Origin: | Malay, Thai |
| Molecular mechanism: | N/A |
| Inheritance: | Recessive |
| DNA Sequence Determined: | Yes |
In silico pathogenicity prediction
Publications / Origin
- Blackwell RQ, Boon WH, Liu CS, Weng MI, Hemoglobin J Singapore: alpha 78 Asn--Asp; alpha 79 Ala--Gly., Biochim. Biophys. Acta , 278(3), 482-90, 1972