6-49431170-T-C

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BS1_Supporting

The NM_000255.4(MMUT):c.*558A>G variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00244 in 152,314 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0024 (1 hom., cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: MMUT NM_000255.4 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.163

Genes affected

MMUT (HGNC:7526): (methylmalonyl-CoA mutase) This gene encodes the mitochondrial enzyme methylmalonyl Coenzyme A mutase. In humans, the product of this gene is a vitamin B12-dependent enzyme which catalyzes the isomerization of methylmalonyl-CoA to succinyl-CoA, while in other species this enzyme may have different functions. Mutations in this gene may lead to various types of methylmalonic aciduria. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.88).
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00244 (372/152314) while in subpopulation AFR AF= 0.00714 (297/41582). AF 95% confidence interval is 0.00647. There are 1 homozygotes in gnomad4. There are 190 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MMUT	NM_000255.4	c.*558A>G		3_prime_UTR_variant	13/13	ENST00000274813.4
MMUT	XM_005249143.4	c.*558A>G		3_prime_UTR_variant	13/13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MMUT	ENST00000274813.4	c.*558A>G		3_prime_UTR_variant	13/13	1	NM_000255.4	P1

Frequencies

GnomAD3 genomes AF: 0.00239 AC: 364 AN: 152196 Hom.: 1 Cov.: 32

Gnomad AFR AF: 0.00697

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000589

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000769

Gnomad SAS AF: 0.000414

Gnomad FIN AF: 0.00471

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000132

Gnomad OTH AF: 0.000479

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 208 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 152

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00244 AC: 372 AN: 152314 Hom.: 1 Cov.: 32 AF XY: 0.00255 AC XY: 190 AN XY: 74482

Gnomad4 AFR AF: 0.00714

Gnomad4 AMR AF: 0.000588

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000770

Gnomad4 SAS AF: 0.000415

Gnomad4 FIN AF: 0.00471

Gnomad4 NFE AF: 0.000132

Gnomad4 OTH AF: 0.000474

Alfa AF: 0.000900 Hom.: 0

Bravo AF: 0.00204

Asia WGS AF: 0.00289 AC: 10 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

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	-0.88
Cadd	Benign	1.4
Dann	Benign	0.54

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

Publications

LitVar

Other links and lift over

dbSNP: rs111322712; hg19: chr6-49398883;