19-39480623-C-T

Variant names:

• chr19-39480623-C-T
• rs773519864
• ENST00000544017.5:c.79C>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PVS1_Strong BS1_Supporting

The ENST00000544017.5(TIMM50):​c.79C>T​(p.Gln27*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000301 in 1,461,812 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: not found (cov: 33)
  • Exomes 𝑓: 0.000030 (0 hom.)
• Consequence: TIMM50 ENST00000544017.5 stop_gained
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.441
• Publications: 0 publications found

Genes affected

TIMM50 (HGNC:23656): (translocase of inner mitochondrial membrane 50) This gene encodes a subunit of the TIM23 inner mitochondrial membrane translocase complex. The encoded protein functions as the receptor subunit that recognizes the mitochondrial targeting signal, or presequence, on protein cargo that is destined for the mitochondrial inner membrane and matrix. This protein may also play a role in maintaining the membrane permeability barrier, and knockdown of this gene in human cells results in the release of cytochrome c and apoptosis. [provided by RefSeq, Jul 2016]

TIMM50 Gene-Disease associations (from GenCC):

• 3-methylglutaconic aciduria type 9

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 9 pathogenic variants in the truncated region.
• BS1: Variant frequency is greater than expected in population sas. GnomAdExome4 allele frequency = 0.0000301 (44/1461812) while in subpopulation SAS AF = 0.000232 (20/86256). AF 95% confidence interval is 0.000153. There are 0 homozygotes in GnomAdExome4. There are 26 alleles in the male GnomAdExome4 subpopulation. Median coverage is 30. 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
TIMM50	NM_001001563.5	c.-231C>T		upstream_gene_variant		ENST00000607714.6	NP_001001563.2
TIMM50	NM_001329559.2	c.-511C>T		upstream_gene_variant			NP_001316488.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TIMM50	ENST00000607714.6	c.-231C>T		upstream_gene_variant		1	NM_001001563.5	ENSP00000475531.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.0000477 AC: 12 AN: 251320 AF XY: 0.0000663

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: 0.00

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.0000301 AC: 44 AN: 1461812 Hom.: 0 Cov.: 30 AF XY: 0.0000358 AC XY: 26 AN XY: 727206

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44688

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.000232 AC: 20 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000198 AC: 22 AN: 1111984

Other (OTH) AF: 0.0000331 AC: 2 AN: 60392

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.0000494 AC: 6

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jan 12, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This variant has not been reported in the literature in individuals affected with TIMM50-related conditions. This variant is present in population databases (rs773519864, gnomAD 0.04%). This sequence change creates a premature translational stop signal (p.Gln27*) in the TIMM50 gene. It is expected to result in an absent or disrupted protein product. However, the current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in TIMM50 cause disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.30	T
BayesDel_noAF	Benign	-0.36
CADD	Benign	1.7
DANN	Benign	0.97
Eigen	Benign	-0.39
Eigen_PC	Benign	-0.88
FATHMM_MKL	Benign	0.0023	N
PhyloP100		-0.44
Vest4		0.067
GERP RS		-7.2
PromoterAI		0.055	Neutral
Mutation Taster		=140/60	disease causing (fs/PTC)

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: rs773519864; hg19: chr19-39971263;