{{Rsnum
|rsid=34139813
|Gene=HBB
|Chromosome=11
|position=5225657
|Orientation=minus
|geno1=(C;C)
|geno2=(C;G)
|geno3=(G;G)
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|Gene_s=HBB
}}[[rs34139813]] is a SNP for the Hemoglobin beta [[HBB]] gene, which is responsible for the protein beta-globin, a component of hemoglobin inside red blood cells. Usually, hemoglobin contains two subunits of beta-globin and two subunits of alpha-globin. Variations in the HBB gene can be unnoticeable, while others may affect a persons health, resulting in various hemoglobin disorders such as beta thalassemia, sickle cell disease, and hemoglobin C.

In 1979, a new mutant hemoglobin with high oxygen affinity was discovered in a Greek family and called Hemoglobin Crete {{PMID|36184}}, but the patients were heterozygous only for Hb Crete and often also had mutations for beta-thalassemia which affects the same gene. This mutant Hb was identified as resulting from a Ala129Pro missense mutation in HBB and identified by sequencing as [[rs34139813]] (G->C) {{PMID|15658190}}. In 2005, a homozygous Hb Crete individual without any additional beta-thalassemia mutations was identified {{PMID|15885607}}.

The Hb Crete phenotype (both homozygous and heterozygous) is associated with erythrocytosis and microcytosis. Hb Crete patients may have functional anemia, with a thalassemic-like phenotype as a result of a deficit of beta-globin chains.  Patients may also have elevated cardiac output ultimately leading to cardiac insufficiency {{PMID|15885607}}.

{{omim
|desc=HEMOGLOBIN--BETA LOCUS; HBB
|id=141900
|rsnum=34139813
|variant=0058
}}
{{omim
|id=141900
|rsnum=34139813
|variant=0500
}}

{{ClinVar
|rsid=34139813
|Reversed=1
|FwdREF=G
|FwdALT=C
|REF=C
|ALT=G
|RSPOS=5246887
|CHROM=11
|dbSNPBuildID=126
|SSR=0
|SAO=1
|VP=0x050368000000000102110100
|GENEINFO=HBB:3043
|GENE_NAME=HBB
|GENE_ID=3043
|WGT=0
|VC=SNV
|CLNALLE=1
|CLNHGVS=NC_000011.9:g.5246887C>G
|CLNORIGIN=1
|CLNSIG=255
|Tags=RV;PM;PMC;S3D;SLO;GNO;OTHERKG;LSD;OM
|CLNACC=RCV000016856.1
|CLNDBN=HEMOGLOBIN MONT SAINT-AIGNAN
|CLNSRC=HBVAR; OMIM Allelic Variant
|CLNSRCID=526; 141900.0500
|Disease=HEMOGLOBIN MONT SAINT-AIGNAN
}}

{{PMID Auto
|PMID=11300350
|Title=Hb Mont Saint Aignan [beta128(H6)Ala-->Pro]: a new unstable variant leading to chronic microcytic anemia.
}}

{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}