1-236874861-T-G

Variant names:

• chr1-236874861-T-G
• rs1770449
• NM_000254.3:c.2594+15T>G

Variant summary

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

The NM_000254.3(MTR):​c.2594+15T>G variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000685 in 1,460,438 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: 32)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: MTR NM_000254.3 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.157
• Publications: 0 publications found

Genes affected

MTR (HGNC:7468): (5-methyltetrahydrofolate-homocysteine methyltransferase) This gene encodes the 5-methyltetrahydrofolate-homocysteine methyltransferase. This enzyme, also known as cobalamin-dependent methionine synthase, catalyzes the final step in methionine biosynthesis. Mutations in MTR have been identified as the underlying cause of methylcobalamin deficiency complementation group G. Alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, May 2014]

MTR Gene-Disease associations (from GenCC):

• methylcobalamin deficiency type cblG

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, ClinGen, Labcorp Genetics (formerly Invitae), G2P

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=-0.82).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000254.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MTR	NM_000254.3	MANE Select	c.2594+15T>G		intron	N/A	NP_000245.2
	MTR	NM_001291939.1		c.2441+15T>G		intron	N/A	NP_001278868.1
	MTR	NM_001410942.1		c.2406-5894T>G		intron	N/A	NP_001397871.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MTR	ENST00000366577.10	TSL:1 MANE Select	c.2594+15T>G		intron	N/A	ENSP00000355536.5
	MTR	ENST00000535889.6	TSL:1	c.2441+15T>G		intron	N/A	ENSP00000441845.1
	MTR	ENST00000366576.3	TSL:1	c.1256+15T>G		intron	N/A	ENSP00000355535.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000685 AC: 10 AN: 1460438 Hom.: 0 Cov.: 34 AF XY: 0.00000551 AC XY: 4 AN XY: 726544

⚠️ 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: 33436

American (AMR) AF: 0.00 AC: 0 AN: 44694

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 39614

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86218

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53318

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000720 AC: 8 AN: 1110950

Other (OTH) AF: 0.0000166 AC: 1 AN: 60328

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.82
CADD	Benign	1.2
DANN	Benign	0.47
PhyloP100		-0.16

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1770449; hg19: chr1-237038161;