1-236795325-C-T

Variant names:

• chr1-236795325-C-T
• rs774502590
• NM_000254.3:c.-379C>T

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000254.3(MTR):​c.-379C>T variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000704 in 1,279,146 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 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000071 (0 hom.)
• Consequence: MTR NM_000254.3 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.711
• 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: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (REVEL=0.021).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MTR	NM_000254.3	c.-379C>T		5_prime_UTR_premature_start_codon_gain_variant	Exon 1 of 33	ENST00000366577.10	NP_000245.2
MTR	NM_000254.3	c.-379C>T		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.-379C>T		5_prime_UTR_premature_start_codon_gain_variant	Exon 1 of 33	1	NM_000254.3	ENSP00000355536.5
MTR	ENST00000366577.10	c.-379C>T		5_prime_UTR_variant	Exon 1 of 33	1	NM_000254.3	ENSP00000355536.5

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152238 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

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: 0.0000942

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000102 AC: 1 AN: 98428 AF XY: 0.0000189

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000513

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000710 AC: 8 AN: 1126908 Hom.: 0 Cov.: 30 AF XY: 0.0000128 AC XY: 7 AN XY: 547366

African (AFR) AF: 0.00 AC: 0 AN: 24662

American (AMR) AF: 0.0000422 AC: 1 AN: 23680

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 14330

East Asian (EAS) AF: 0.00 AC: 0 AN: 15498

South Asian (SAS) AF: 0.0000144 AC: 1 AN: 69516

European-Finnish (FIN) AF: 0.0000776 AC: 1 AN: 12890

Middle Eastern (MID) AF: 0.000460 AC: 2 AN: 4344

European-Non Finnish (NFE) AF: 0.00000217 AC: 2 AN: 919878

Other (OTH) AF: 0.0000237 AC: 1 AN: 42110

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152238 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74374

African (AFR) AF: 0.00 AC: 0 AN: 41462

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

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4836

European-Finnish (FIN) AF: 0.0000942 AC: 1 AN: 10620

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68044

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

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	-0.76
CADD	Benign	5.3
DANN	Benign	0.72
PhyloP100		-0.71
PromoterAI		-0.15	Neutral

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: rs774502590; hg19: chr1-236958625;