22-42636864-G-A

Variant names:

• chr22-42636864-G-A
• rs2285141
• NM_000398.7:c.22-18C>T

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.22-18C>T variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000869 in 1,611,554 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: CYB5R3 NM_000398.7 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.336
• Publications: 20 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: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• hereditary methemoglobinemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

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 (BayesDel_noAF=-0.89).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CYB5R3	NM_000398.7	c.22-18C>T		intron_variant	Intron 1 of 8	ENST00000352397.10	NP_000389.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CYB5R3	ENST00000352397.10	c.22-18C>T		intron_variant	Intron 1 of 8	1	NM_000398.7	ENSP00000338461.6

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152116 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.00316

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.000479

GnomAD2 exomes AF: 0.0000162 AC: 4 AN: 246602 AF XY: 0.0000150

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000582

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000179

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000754 AC: 11 AN: 1459320 Hom.: 0 Cov.: 33 AF XY: 0.00000827 AC XY: 6 AN XY: 725926

African (AFR) AF: 0.00 AC: 0 AN: 33450

American (AMR) AF: 0.0000449 AC: 2 AN: 44582

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26116

East Asian (EAS) AF: 0.00 AC: 0 AN: 39568

South Asian (SAS) AF: 0.00 AC: 0 AN: 86136

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52024

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000810 AC: 9 AN: 1111358

Other (OTH) AF: 0.00 AC: 0 AN: 60320

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152234 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74430

African (AFR) AF: 0.00 AC: 0 AN: 41568

American (AMR) AF: 0.00 AC: 0 AN: 15294

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5152

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10600

Middle Eastern (MID) AF: 0.00340 AC: 1 AN: 294

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68012

Other (OTH) AF: 0.000474 AC: 1 AN: 2110

Alfa AF: 0.00000750 Hom.: 1140

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.89
CADD	Benign	0.29
DANN	Benign	0.71
PhyloP100		-0.34
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.3

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

Other links and lift over

dbSNP: rs2285141; hg19: chr22-43032870;