NM_000254.3:c.-173G>A

Variant names:

• chr1-236795531-G-A
• rs3738548
• NM_000254.3:c.-173G>A

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_Moderate BS1_Supporting

The NM_000254.3(MTR):​c.-173G>A variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000947 in 1,530,420 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 0.000053 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000099 (0 hom.)
• Consequence: MTR NM_000254.3 5_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.21
• Publications: 1 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 -3 ACMG points.

• BP4: Computational evidence support a benign effect (REVEL=0.023).
• BS1: Variant frequency is greater than expected in population eas. GnomAdExome4 allele frequency = 0.0000994 (137/1378192) while in subpopulation EAS AF = 0.000903 (32/35446). AF 95% confidence interval is 0.000657. There are 0 homozygotes in GnomAdExome4. There are 72 alleles in the male GnomAdExome4 subpopulation. Median coverage is 31. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MTR	NM_000254.3	c.-173G>A		5_prime_UTR_variant	Exon 1 of 33	ENST00000366577.10	NP_000245.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MTR	ENST00000366577.10	c.-173G>A		5_prime_UTR_variant	Exon 1 of 33	1	NM_000254.3	ENSP00000355536.5

Frequencies

GnomAD3 genomes AF: 0.0000526 AC: 8 AN: 152228 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000965

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

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: 0.0000441

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000705 AC: 10 AN: 141910 AF XY: 0.0000518

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000270

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000105

Gnomad OTH exome AF: 0.000236

GnomAD4 exome AF: 0.0000994 AC: 137 AN: 1378192 Hom.: 0 Cov.: 31 AF XY: 0.000106 AC XY: 72 AN XY: 680516

African (AFR) AF: 0.0000636 AC: 2 AN: 31450

American (AMR) AF: 0.00 AC: 0 AN: 35594

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 24914

East Asian (EAS) AF: 0.000903 AC: 32 AN: 35446

South Asian (SAS) AF: 0.00 AC: 0 AN: 79078

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 33862

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5646

European-Non Finnish (NFE) AF: 0.0000912 AC: 98 AN: 1074730

Other (OTH) AF: 0.0000870 AC: 5 AN: 57472

GnomAD4 genome AF: 0.0000526 AC: 8 AN: 152228 Hom.: 0 Cov.: 33 AF XY: 0.0000941 AC XY: 7 AN XY: 74360

African (AFR) AF: 0.0000965 AC: 4 AN: 41468

American (AMR) AF: 0.0000654 AC: 1 AN: 15288

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5182

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

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

European-Non Finnish (NFE) AF: 0.0000441 AC: 3 AN: 68044

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.000109 Hom.: 0

Bravo AF: 0.0000416

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Disorders of Intracellular Cobalamin Metabolism Uncertain:1

Jan 12, 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	-0.81
CADD	Benign	2.5
DANN	Benign	0.83
PhyloP100		-1.2
PromoterAI		-0.046	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0

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: rs3738548; hg19: chr1-236958831;