rs34474104

Positions:

• chr11-5254417-G-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_000184.3(HBG2):​c.190C>T​(p.His64Tyr) 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H64L) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: HBG2 NM_000184.3 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 6.38

Genes affected

HBG2 (HGNC:4832): (hemoglobin subunit gamma 2) The gamma globin genes (HBG1 and HBG2) are normally expressed in the fetal liver, spleen and bone marrow. Two gamma chains together with two alpha chains constitute fetal hemoglobin (HbF) which is normally replaced by adult hemoglobin (HbA) at birth. In some beta-thalassemias and related conditions, gamma chain production continues into adulthood. The two types of gamma chains differ at residue 136 where glycine is found in the G-gamma product (HBG2) and alanine is found in the A-gamma product (HBG1). The former is predominant at birth. 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]

ENSG00000284931 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PM1: In a binding_site distal binding residue (size 0) in uniprot entity HBG2_HUMAN
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989
• PP5: Variant 11-5254417-G-A is Pathogenic according to our data. Variant chr11-5254417-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 14981.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HBG2	NM_000184.3	c.190C>T	p.His64Tyr	missense_variant	2/3	ENST00000336906.6	NP_000175.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HBG2	ENST00000336906.6	c.190C>T	p.His64Tyr	missense_variant	2/3	1	NM_000184.3	ENSP00000338082.4
ENSG00000284931	ENST00000642908.1	c.190C>T	p.His64Tyr	missense_variant	2/3			ENSP00000495346.1
ENSG00000239920	ENST00000380259.7	n.*1493C>T		non_coding_transcript_exon_variant	8/8	5		ENSP00000369609.3
ENSG00000239920	ENST00000380259.7	n.*1493C>T		3_prime_UTR_variant	8/8	5		ENSP00000369609.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Cyanosis, transient neonatal Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jan 01, 2008

- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 17, 2024

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Also known as Hb FM-Osaka and p.(H63Y); This variant is associated with the following publications: (PMID: 19065339, 2470018, 38415208, 6158500, 8811323, Chandran2022[CaseReport], 31970190, 12603090) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.48	D
BayesDel_noAF	Pathogenic	0.45
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Benign	0.29	.;.;T;.
Eigen	Uncertain	0.30
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.91	D;D;D;D
M_CAP	Uncertain	0.21	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	.;.;H;.
PROVEAN	Pathogenic	-5.7	.;.;D;.
REVEL	Pathogenic	0.88
Sift	Uncertain	0.013	.;.;D;.
Sift4G	Uncertain	0.0050	.;.;D;.
Polyphen		0.15	.;.;B;.
Vest4		0.68
MutPred		0.96		Loss of disorder (P = 0.0351);Loss of disorder (P = 0.0351);Loss of disorder (P = 0.0351);.;
MVP		0.93
ClinPred		0.88	D
GERP RS		3.9
RBP_binding_hub_radar		1.1
RBP_regulation_power_radar		2.3
Varity_R		0.71
gMVP		0.96

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: rs34474104; hg19: chr11-5275647;