rs33940204

Positions:

• chr11-5226626-A-C
• chr11-5226626-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_000518.5(HBB):​c.266T>G​(p.Leu89Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic,other (no stars). Another nucleotide change resulting in same amino acid change has been previously reported as Likely benignin UniProt. Synonymous variant affecting the same amino acid position (i.e. L89L) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: HBB NM_000518.5 missense
• Clinical Significance: Pathogenic; other no assertion criteria provided P:1 O:1
• Conservation: PhyloP100: 8.51

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 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989
• PP5: Variant 11-5226626-A-C is Pathogenic according to our data. Variant chr11-5226626-A-C is described in ClinVar as [Pathogenic, other]. Clinvar id is 15108.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HBB	NM_000518.5	c.266T>G	p.Leu89Arg	missense_variant	2/3	ENST00000335295.4	NP_000509.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HBB	ENST00000335295.4	c.266T>G	p.Leu89Arg	missense_variant	2/3	1	NM_000518.5	ENSP00000333994.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 36

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic; other

Submissions summary: Pathogenic:1 Other:1

Revision: no assertion criteria provided

Submissions by phenotype

HBB-related disorder Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

May 27, 2024

The HBB c.266T>G variant is predicted to result in the amino acid substitution p.Leu89Arg. This variant, also referred to as Hb Borås and p.Leu88Arg using legacy nomenclature, has been reported in individuals with anemia (Hollender et al. 1969. PubMed ID: 5789325; Bird et al. 1987. PubMed ID: 3623976; Bae et al. 2023. PubMed ID: 37665291) and has been demonstrated to result in tetramer instability (Hollender et al. 1969. PubMed ID: 5789325). This variant has not been reported in a large population database, indicating this variant is rare. A different missense change impacting the same amino acid (p.Leu89Pro, also referred as Hb Santa Ana) has been reported to be causative for anemia (Goncalves et al. 1994. PubMed ID: 7928381). This variant is interpreted as pathogenic. -

HEMOGLOBIN BORAS Other:1

other, no assertion criteria provided

literature only

OMIM

Dec 12, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.29	T;T;.;T
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	.;D;D;T
M_CAP	Pathogenic	0.54	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.6	H;H;.;.
PrimateAI	Uncertain	0.69	T
PROVEAN	Pathogenic	-5.8	D;.;.;D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;.;.;D
Sift4G	Pathogenic	0.0	D;.;.;.
Polyphen		1.0	D;D;.;.
Vest4		1.0
MutPred		0.94		Gain of methylation at L89 (P = 0.0373);Gain of methylation at L89 (P = 0.0373);Gain of methylation at L89 (P = 0.0373);Gain of methylation at L89 (P = 0.0373);
MVP		0.95
MPC		0.29
ClinPred		0.99	D
GERP RS		5.2
Varity_R		0.97
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs33940204; hg19: chr11-5247856;