22-42619495-C-T

Variant names:

• chr22-42619495-C-T
• rs145166392
• NM_000398.7:c.*278G>A

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.*278G>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000785 in 509,554 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 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000056 (0 hom.)
• Consequence: CYB5R3 NM_000398.7 3_prime_UTR
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -5.26
• Publications: 0 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 (BayesDel_noAF=-0.87).

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.*278G>A		3_prime_UTR	Exon 9 of 9	NP_000389.1	P00387-1
	CYB5R3	NM_001171660.2		c.*278G>A		3_prime_UTR	Exon 9 of 9	NP_001165131.1	P00387-3
	CYB5R3	NM_001129819.2		c.*278G>A		3_prime_UTR	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.*278G>A		3_prime_UTR	Exon 9 of 9	ENSP00000338461.6	P00387-1
	CYB5R3	ENST00000407332.6	TSL:1	c.*278G>A		3_prime_UTR	Exon 9 of 9	ENSP00000384457.2	A0A8J8Z3C6
	CYB5R3	ENST00000470741.1	TSL:1	n.3318G>A		non_coding_transcript_exon	Exon 6 of 6

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 152028 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.000288

Gnomad EAS AF: 0.000193

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000560 AC: 2 AN: 357408 Hom.: 0 Cov.: 0 AF XY: 0.0000107 AC XY: 2 AN XY: 186822

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 10480

American (AMR) AF: 0.00 AC: 0 AN: 15520

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 11228

East Asian (EAS) AF: 0.0000413 AC: 1 AN: 24214

South Asian (SAS) AF: 0.0000250 AC: 1 AN: 39948

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 22488

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 1584

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 211322

Other (OTH) AF: 0.00 AC: 0 AN: 20624

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00666416), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152146 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74380

African (AFR) AF: 0.00 AC: 0 AN: 41510

American (AMR) AF: 0.00 AC: 0 AN: 15280

Ashkenazi Jewish (ASJ) AF: 0.000288 AC: 1 AN: 3470

East Asian (EAS) AF: 0.000194 AC: 1 AN: 5162

South Asian (SAS) AF: 0.00 AC: 0 AN: 4816

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67996

Other (OTH) AF: 0.00 AC: 0 AN: 2106

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000113

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.87
CADD	Benign	0.39
DANN	Benign	0.84
PhyloP100		-5.3
RBP_binding_hub_radar		0.97
RBP_regulation_power_radar		2.1

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: rs145166392; hg19: chr22-43015501;