rs3776455

Variant names:

• chr5-7896398-C-G
• rs3776455
• NM_002454.3:c.1677-466C>G

Your query was ambiguous. Multiple possible variants found:

• chr5-7896398-C-G
• chr5-7896398-C-T

Variant summary

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

The NM_002454.3(MTRR):​c.1677-466C>G variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000189 in 53,042 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: not found (cov: 33)
  • Exomes 𝑓: 0.000019 (0 hom.)
• Consequence: MTRR NM_002454.3 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.0470
• Publications: 0 publications found

Genes affected

MTRR (HGNC:7473): (5-methyltetrahydrofolate-homocysteine methyltransferase reductase) This gene encodes a member of the ferredoxin-NADP(+) reductase (FNR) family of electron transferases. This protein functions in the synthesis of methionine by regenerating methionine synthase to a functional state. Because methionine synthesis requires methyl-group transfer by a folate donor, activity of the encoded enzyme is important for folate metabolism and cellular methylation. Mutations in this gene can cause homocystinuria-megaloblastic anemia, cbl E type. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, Dec 2015]

MTRR Gene-Disease associations (from GenCC):

• methylcobalamin deficiency type cblE

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, G2P, 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=-0.91).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MTRR	NM_002454.3	c.1677-466C>G		intron_variant	Intron 12 of 14	ENST00000440940.7	NP_002445.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MTRR	ENST00000440940.7	c.1677-466C>G		intron_variant	Intron 12 of 14	1	NM_002454.3	ENSP00000402510.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.0000189 AC: 1 AN: 53042 Hom.: 0 Cov.: 0 AF XY: 0.0000364 AC XY: 1 AN XY: 27446

⚠️ 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: 736

American (AMR) AF: 0.00 AC: 0 AN: 3582

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 1110

East Asian (EAS) AF: 0.00 AC: 0 AN: 2538

South Asian (SAS) AF: 0.00 AC: 0 AN: 6856

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 2090

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 174

European-Non Finnish (NFE) AF: 0.0000303 AC: 1 AN: 33046

Other (OTH) AF: 0.00 AC: 0 AN: 2910

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.91
CADD	Benign	0.18
DANN	Benign	0.53
PhyloP100		-0.047

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: rs3776455; hg19: chr5-7896511;