11-5226755-A-G

Position:

• chr11-5226755-A-G

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP3_Strong PP5

The NM_000518.5(HBB):​c.137T>C​(p.Phe46Ser) variant causes a missense change. 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 Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in same amino acid change has been previously reported as Likely benignin UniProt. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. F46C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: HBB NM_000518.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1 O:1
• Conservation: PhyloP100: 5.61

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]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 5 benign, 15 uncertain in NM_000518.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr11-5226756-A-C is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984
• PP5: Variant 11-5226755-A-G is Pathogenic according to our data. Variant chr11-5226755-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 15135.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HBB	NM_000518.5	c.137T>C	p.Phe46Ser	missense_variant	2/3	ENST00000335295.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HBB	ENST00000335295.4	c.137T>C	p.Phe46Ser	missense_variant	2/3	1	NM_000518.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 36

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1 Other:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Jul 30, 2017

- -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Feb 01, 2023

Variant summary: HBB c.137T>C (p.Phe46Ser), also referred to as Hb Cheverly, results in a non-conservative amino acid change located in the globin (IPR000971) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251414 control chromosomes (gnomAD). c.137T>C has been reported in the literature in the heterozygous state in individuals affected with mild anemia and in individuals with low peripheral oxygen saturation detected by pulse oximetry, but with normal arterial oxygen saturation who are otherwise asymptomatic (e.g. Yeager_1983, Hohl_1998, Yodfat_2006, van Zwieten_2014, Chow_2021). Experimental evidence evaluating an impact on protein function suggests Hb Cheverly is unstable and has a reduced oxygen affinity and a Bohr effect approximately two-thirds of normal (Yeager_1983). Two submitters have provided clinical-significance assessments for this variant to ClinVar after 2014. One laboratory classified the variant as likely pathogenic and the other submitter has not provided a classification. Based on the evidence outlined above, the variant was classified as VUS. -

HEMOGLOBIN CHEVERLY 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	0.98
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.24	T;T;.;T
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.91	.;D;D;D
M_CAP	Pathogenic	0.62	D
MetaRNN	Pathogenic	0.98	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.5	H;H;.;.
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-7.0	D;.;.;D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;.;.;D
Sift4G	Uncertain	0.024	D;.;.;.
Polyphen		1.0	D;D;.;.
Vest4		0.97
MutPred		0.91		Gain of disorder (P = 0.0017);Gain of disorder (P = 0.0017);Gain of disorder (P = 0.0017);Gain of disorder (P = 0.0017);
MVP		0.94
MPC		0.30
ClinPred		0.99	D
GERP RS		5.1
Varity_R		0.94
gMVP		0.99

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: rs33978338; hg19: chr11-5247985;