3-48857717-T-C

Position:

• chr3-48857717-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_000387.6(SLC25A20):​c.899A>G​(p.Asn300Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SLC25A20 NM_000387.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.49

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 Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a chain Mitochondrial carnitine/acylcarnitine carrier protein (size 299) in uniprot entity MCAT_HUMAN there are 12 pathogenic changes around while only 3 benign (80%) in NM_000387.6
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.1801422).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SLC25A20	NM_000387.6	c.899A>G	p.Asn300Ser	missense_variant	9/9	ENST00000319017.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SLC25A20	ENST00000319017.5	c.899A>G	p.Asn300Ser	missense_variant	9/9	1	NM_000387.6	P1
SLC25A20	ENST00000430379.5	c.680A>G	p.Asn227Ser	missense_variant	7/7	3
SLC25A20	ENST00000479050.1	n.218A>G		non_coding_transcript_exon_variant	2/2	2
SLC25A20	ENST00000440964.1	c.*729A>G		3_prime_UTR_variant, NMD_transcript_variant	10/10	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000370 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Carnitine acylcarnitine translocase deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 10, 2023

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. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant  is likely to be tolerated. This variant has not been reported in the literature in individuals affected with SLC25A20-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 300 of the SLC25A20 protein (p.Asn300Ser). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.069
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.42
CADD	Benign	18
DANN	Uncertain	0.99
DEOGEN2	Benign	0.17	.;T
Eigen	Benign	-0.091
Eigen_PC	Benign	0.090
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Benign	0.56	T;T
M_CAP	Benign	0.047	D
MetaRNN	Benign	0.18	T;T
MetaSVM	Benign	-0.83	T
MutationAssessor	Benign	0.90	.;L
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Benign	0.39	T
PROVEAN	Benign	-1.9	N;N
REVEL	Benign	0.25
Sift	Benign	0.16	T;T
Sift4G	Benign	0.42	T;T
Polyphen		0.032	B;B
Vest4		0.13
MVP		0.87
MPC		0.21
ClinPred		0.32	T
GERP RS		5.7
Varity_R		0.038
gMVP		0.76

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: rs2083590517; hg19: chr3-48895150;