rs756998699

chr3-48898785-G-Achr3-48898785-G-Cchr3-48898785-G-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000387.6(SLC25A20):c.10C>T(p.Gln4Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000012 in 1,421,010 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000012 (0 hom.)
• Consequence: SLC25A20 NM_000387.6 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 0.440

Genes affected

SLC25A20 (HGNC:1421): (solute carrier family 25 member 20) This gene product is one of several closely related mitochondrial-membrane carrier proteins that shuttle substrates between cytosol and the intramitochondrial matrix space. This protein mediates the transport of acylcarnitines into mitochondrial matrix for their oxidation by the mitochondrial fatty acid-oxidation pathway. Mutations in this gene are associated with carnitine-acylcarnitine translocase deficiency, which can cause a variety of pathological conditions such as hypoglycemia, cardiac arrest, hepatomegaly, hepatic dysfunction and muscle weakness, and is usually lethal in new born and infants. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 18 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 33 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-48898785-G-A is Pathogenic according to our data. Variant chr3-48898785-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 203941.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SLC25A20	NM_000387.6	c.10C>T	p.Gln4Ter	stop_gained	1/9	ENST00000319017.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SLC25A20	ENST00000319017.5	c.10C>T	p.Gln4Ter	stop_gained	1/9	1	NM_000387.6	P1
SLC25A20	ENST00000430379.5	c.10C>T	p.Gln4Ter	stop_gained	1/7	3
SLC25A20	ENST00000440964.1	c.10C>T	p.Gln4Ter	stop_gained, NMD_transcript_variant	1/10	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.0000120 AC: 17 AN: 1421010 Hom.: 0 Cov.: 31 AF XY: 0.00000995 AC XY: 7 AN XY: 703284

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000156

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000282 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.0000339 AC: 4

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Carnitine acylcarnitine translocase deficiency Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 20, 2023	Variant summary: SLC25A20 c.10C>T (p.Gln4X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The next downstream in-frame ATG start site is at codon 51 (Exon 2). Truncations downstream of this variant's position, including those 5 of the next downstream putative in-frame start codon, have been classified as pathogenic by our laboratory. The variant was absent in 181278 control chromosomes. To our knowledge, no occurrence of c.10C>T in individuals affected with Carnitine-Acylcarnitine Translocase Deficiency and no experimental evidence demonstrating its impact on protein function have been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014, and all laboratories classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Oct 17, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 01, 2024	This sequence change creates a premature translational stop signal (p.Gln4*) in the SLC25A20 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in SLC25A20 are known to be pathogenic (PMID: 25614308). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with SLC25A20-related conditions. ClinVar contains an entry for this variant (Variation ID: 203941). For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Apr 02, 2022

Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.010
Cadd	Pathogenic	29
Dann	Uncertain	0.99
Eigen	Benign	0.065
Eigen_PC	Benign	-0.27
FATHMM_MKL	Benign	0.45	N
MutationTaster	Benign	1.0	A;A;N
Vest4		0.39
GERP RS		-4.2
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

Publications

LitVar

Other links and lift over

dbSNP: rs756998699; hg19: chr3-48936218;