22-42619809-G-C

Variant names:

• chr22-42619809-G-C
• rs762602202
• NM_000398.7:c.870C>G

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000398.7(CYB5R3):​c.870C>G​(p.His290Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000138 in 1,446,288 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. H290H) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000014 (0 hom.)
• Consequence: CYB5R3 NM_000398.7 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.332
• Publications: 1 publications found

Genes affected

CYB5R3 (HGNC:2873): (cytochrome b5 reductase 3) This gene encodes cytochrome b5 reductase, which includes a membrane-bound form in somatic cells (anchored in the endoplasmic reticulum, mitochondrial and other membranes) and a soluble form in erythrocytes. The membrane-bound form exists mainly on the cytoplasmic side of the endoplasmic reticulum and functions in desaturation and elongation of fatty acids, in cholesterol biosynthesis, and in drug metabolism. The erythrocyte form is located in a soluble fraction of circulating erythrocytes and is involved in methemoglobin reduction. The membrane-bound form has both membrane-binding and catalytic domains, while the soluble form has only the catalytic domain. Alternate splicing results in multiple transcript variants. Mutations in this gene cause methemoglobinemias. [provided by RefSeq, Jan 2010]

CYB5R3 Gene-Disease associations (from GenCC):

• methemoglobinemia

  Inheritance: AR Classification: DEFINITIVE Submitted by: Illumina
• methemoglobinemia due to deficiency of methemoglobin reductase

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, ClinGen, Labcorp Genetics (formerly Invitae)
• hereditary methemoglobinemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000289517 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.06651625).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000398.7. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CYB5R3	NM_000398.7	MANE Select	c.870C>G	p.His290Gln	missense	Exon 9 of 9	NP_000389.1	P00387-1
	CYB5R3	NM_001171660.2		c.969C>G	p.His323Gln	missense	Exon 9 of 9	NP_001165131.1	P00387-3
	CYB5R3	NM_001129819.2		c.801C>G	p.His267Gln	missense	Exon 9 of 9	NP_001123291.1	P00387-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CYB5R3	ENST00000352397.10	TSL:1 MANE Select	c.870C>G	p.His290Gln	missense	Exon 9 of 9	ENSP00000338461.6	P00387-1
	CYB5R3	ENST00000407332.6	TSL:1	c.888C>G	p.His296Gln	missense	Exon 9 of 9	ENSP00000384457.2	A0A8J8Z3C6
	CYB5R3	ENST00000470741.1	TSL:1	n.3004C>G		non_coding_transcript_exon	Exon 6 of 6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.0000138 AC: 20 AN: 1446288 Hom.: 0 Cov.: 32 AF XY: 0.0000111 AC XY: 8 AN XY: 718090

African (AFR) AF: 0.00 AC: 0 AN: 33390

American (AMR) AF: 0.00 AC: 0 AN: 42156

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25712

East Asian (EAS) AF: 0.00 AC: 0 AN: 39114

South Asian (SAS) AF: 0.00 AC: 0 AN: 83752

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49834

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5750

European-Non Finnish (NFE) AF: 0.0000181 AC: 20 AN: 1106646

Other (OTH) AF: 0.00 AC: 0 AN: 59934

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Inborn genetic diseases (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.013	T
BayesDel_noAF	Benign	-0.26
CADD	Benign	15
DANN	Benign	0.91
DEOGEN2	Benign	0.042	T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.44	N
LIST_S2	Benign	0.74	T
M_CAP	Benign	0.047	D
MetaRNN	Benign	0.067	T
MetaSVM	Benign	-0.60	T
MutationAssessor	Benign	-1.2	N
PhyloP100		0.33
PrimateAI	Benign	0.37	T
PROVEAN	Benign	1.3	N
REVEL	Benign	0.26
Sift	Uncertain	0.027	D
Sift4G	Benign	0.064	T
Polyphen		0.0	B
Vest4		0.13
MutPred		0.38		Loss of catalytic residue at D289 (P = 0.0628)
MVP		0.78
MPC		0.038
ClinPred		0.32	T
GERP RS		-5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.20
gMVP		0.49
Mutation Taster		=95/5	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs762602202; hg19: chr22-43015815;