NM_000518.5:c.316-7C>A

Variant names:

• chr11-5225733-G-T
• rs34483965
• NM_000518.5:c.316-7C>A

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 1P and 1B. PP5 BP4

The NM_000518.5(HBB):​c.316-7C>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,613,938 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: HBB NM_000518.5 splice_region, intron
• Scores: Splicing: ADA: 0.001439
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:5 U:2
• Conservation: PhyloP100: 0.474
• Publications: 6 publications found

Genes affected

HBB (HGNC:4827): (hemoglobin subunit beta) The alpha (HBA) and beta (HBB) loci determine the structure of the 2 types of polypeptide chains in adult hemoglobin, Hb A. The normal adult hemoglobin tetramer consists of two alpha chains and two beta chains. Mutant beta globin causes sickle cell anemia. Absence of beta chain causes beta-zero-thalassemia. Reduced amounts of detectable beta globin causes beta-plus-thalassemia. The order of the genes in the beta-globin cluster is 5'-epsilon -- gamma-G -- gamma-A -- delta -- beta--3'. [provided by RefSeq, Jul 2008]

HBB Gene-Disease associations (from GenCC):

• dominant beta-thalassemia

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen
• hemoglobin M disease

  Inheritance: AD Classification: DEFINITIVE, MODERATE, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, ClinGen
• beta thalassemia

  Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
• beta-thalassemia HBB/LCRB

  Inheritance: AR, SD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
• sickle cell disease and related diseases

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• erythrocytosis, familial, 6

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• Heinz body anemia

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• sickle cell disease

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
• hereditary persistence of fetal hemoglobin-beta-thalassemia syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• beta-thalassemia intermedia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• beta-thalassemia major

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• delta-beta-thalassemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hemoglobin C disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hemoglobin C-beta-thalassemia syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hemoglobin E disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hemoglobin E-beta-thalassemia syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary persistence of fetal hemoglobin-sickle cell disease syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• sickle cell-beta-thalassemia disease syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• sickle cell-hemoglobin c disease syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• sickle cell-hemoglobin d disease syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• sickle cell-hemoglobin E disease syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000298932 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PP5: Variant 11-5225733-G-T is Pathogenic according to our data. Variant chr11-5225733-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 551906.
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.73). . Strength limited to SUPPORTING due to the PP5.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000518.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HBB	NM_000518.5	MANE Select	c.316-7C>A		splice_region intron	N/A	NP_000509.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HBB	ENST00000335295.4	TSL:1 MANE Select	c.316-7C>A		splice_region intron	N/A	ENSP00000333994.3
	HBB	ENST00000647020.1		c.316-7C>A		splice_region intron	N/A	ENSP00000494175.1
	HBB	ENST00000475226.1	TSL:2	n.248-7C>A		splice_region intron	N/A

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152172 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000966

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251142 AF XY: 0.00

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000410 AC: 6 AN: 1461766 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727210

African (AFR) AF: 0.000149 AC: 5 AN: 33478

American (AMR) AF: 0.0000224 AC: 1 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53404

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111926

Other (OTH) AF: 0.00 AC: 0 AN: 60390

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152172 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74338

African (AFR) AF: 0.0000966 AC: 4 AN: 41428

American (AMR) AF: 0.00 AC: 0 AN: 15270

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5202

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68030

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.0000282 Hom.: 0

Bravo AF: 0.0000416

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:5 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not specified Pathogenic:1 Uncertain:1

Jun 26, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: HBB c.316-7C>A alters a nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Consensus agreement among computation tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 4e-06 in 251142 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.316-7C>A has been observed as a compound heterozygous genotype with the HbS variant in at-least one individual with features of Sickle liver disease (Cross_2007) and as a complex allele in cis with c.316-12T>C (legacy name IVS-II-839T>C) in individuals affected with mild Beta Thalassemia (Waye_2013, Belisario_2013). As the possibility of incomplete genotyping in the earlier report (Cross_2007) cannot be entirely excluded, these data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 26041423, 31589614, 17565724, 23651435). ClinVar contains an entry for this variant (Variation ID: 551906). Based on the evidence outlined above, the variant was classified as uncertain significance.

Sep 27, 2018

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.[316-12T>C; 316-7C>A] complex variant is reported in the literature in multiple individuals as a very mild beta + thalassemia trait (Belisario 2015, Waye 2013), and has been found in trans with Hb S and Hb C in patients with clinical symptoms (Cross 2007, Belisario 2015, Waye 2013). The c.316-12T>C variant (rs755236703) is only observed on three alleles in the Genome Aggregation Database. The c.316-7C>A variant (rs34483965) is only observed on one allele in the Genome Aggregation Database. These are intronic variants in weakly conserved nucleotides, and computational analyses (Alamut v.2.11) predict that each variant may impact splicing by weakening the nearby canonical acceptor splice site, however, without mRNA analysis it is unclear how the combination of the two variants impact splicing. Based on available information, the c.[316-12T>C; 316-7C>A] complex variant is considered to be likely pathogenic. References: Belisario A et al. Very mild forms of Hb S/beta(+)-thalassemia in Brazilian children. Rev Bras Hematol Hemoter. 2015 37(3):198-201. Cross T et al. Sickle liver disease--an unusual presentation in a compound heterozygote for HbS and a novel beta-thalassemia mutation. Am J Hematol. 2007 82(9):852-4. Waye J et al. Mild beta(+)-thalassemia associated with two linked sequence variants: IVS-II-839 (T>C) and IVS-II-844 (C>A). Hemoglobin. 2013 37(4):378-86.

not provided Pathogenic:1 Uncertain:1

Aug 07, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. ClinVar contains an entry for this variant (Variation ID: 551906). This variant is also known as IVS2-844C>A. This variant has been observed in individual(s) with HBB-related conditions (PMID: 17565724, 23651435, 26041423). In some individuals, it has been found in cis (on the same chromosome) with c.316-12T>C. In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is present in population databases (no rsID available, gnomAD 0.007%). This sequence change falls in intron 2 of the HBB gene. It does not directly change the encoded amino acid sequence of the HBB protein.

Jul 12, 2024

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The HBB c.316-7C>A variant has been reported in the published literature in an individual carrying Hb S with very mild clinical presentation (PMID: 17565724 (2007)). It is commonly found as a complex allele with the HBB c.316-12T>C variant, and the (c.316-12T>C; c.316-7C>A) complex allele is reported as being associated with mild beta(+)-thalassemia when it occurs in trans with Hb S or Hb C (PMID: 26041423 (2015), 23651435 (2013)).The frequency of this variant in the general population, 0.000004 (1/251142 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Analysis of this variant using software algorithms for the prediction of the effect of nucleotide changes on HBB mRNA splicing yielded inconclusive findings (Alamut Visual (http://www.interactive-biosoftware.com/)). Based on the available information, we are unable to determine the clinical significance of this variant.

beta Thalassemia Pathogenic:1

Jul 17, 2017

Natera, Inc.

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

Beta-thalassemia HBB/LCRB Pathogenic:1

May 22, 2017

Counsyl

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.

Hb SS disease Pathogenic:1

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.73
CADD	Benign	8.0
DANN	Benign	0.70
PhyloP100		0.47
Mutation Taster		=40/60	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.0014
dbscSNV1_RF	Benign	0.12
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs34483965; hg19: chr11-5246963;