1-236795291-C-A

Variant names:

• chr1-236795291-C-A
• rs556504622
• ENST00000680454.1:n.32C>A

Variant summary

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

The ENST00000680454.1(MTR):​n.32C>A variant causes a non coding transcript exon change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000554 in 1,209,078 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000054 (0 hom.)
• Consequence: MTR ENST00000680454.1 non_coding_transcript_exon
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.97
• 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=-0.77).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MTR	NM_000254.3	c.-413C>A		upstream_gene_variant		ENST00000366577.10	NP_000245.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MTR	ENST00000366577.10	c.-413C>A		upstream_gene_variant		1	NM_000254.3	ENSP00000355536.5

Frequencies

GnomAD3 genomes AF: 0.0000657 AC: 10 AN: 152232 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

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: 0.00

Gnomad NFE AF: 0.000103

Gnomad OTH AF: 0.000956

GnomAD2 exomes AF: 0.000106 AC: 7 AN: 65924 AF XY: 0.000148

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000277

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000539 AC: 57 AN: 1056846 Hom.: 0 Cov.: 30 AF XY: 0.0000572 AC XY: 29 AN XY: 506910

African (AFR) AF: 0.00 AC: 0 AN: 22070

American (AMR) AF: 0.0000641 AC: 1 AN: 15610

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 10716

East Asian (EAS) AF: 0.00 AC: 0 AN: 12622

South Asian (SAS) AF: 0.00 AC: 0 AN: 62212

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 9772

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4006

European-Non Finnish (NFE) AF: 0.0000613 AC: 54 AN: 881624

Other (OTH) AF: 0.0000523 AC: 2 AN: 38214

GnomAD4 genome AF: 0.0000657 AC: 10 AN: 152232 Hom.: 0 Cov.: 33 AF XY: 0.0000538 AC XY: 4 AN XY: 74378

African (AFR) AF: 0.0000241 AC: 1 AN: 41468

American (AMR) AF: 0.00 AC: 0 AN: 15290

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5188

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10626

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.000103 AC: 7 AN: 68042

Other (OTH) AF: 0.000956 AC: 2 AN: 2092

Alfa AF: 0.0000693 Hom.: 0

Bravo AF: 0.0000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Disorders of Intracellular Cobalamin Metabolism Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.77
CADD	Benign	0.51
DANN	Benign	0.59
PhyloP100		-2.0
PromoterAI		-0.0058	Neutral

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs556504622; hg19: chr1-236958591;