20-761090-G-C

Position:

• chr20-761090-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_033409.4(SLC52A3):​c.1346C>G​(p.Pro449Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000048 in 1,457,066 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 Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: SLC52A3 NM_033409.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.60

Genes affected

SLC52A3 (HGNC:16187): (solute carrier family 52 member 3) This gene encodes a riboflavin transporter protein that is strongly expressed in the intestine and likely plays a role in intestinal absorption of riboflavin. The protein is predicted to have eleven transmembrane domains and a cell surface localization signal in the C-terminus. Mutations at this locus have been associated with Brown-Vialetto-Van Laere syndrome and Fazio-Londe disease. [provided by RefSeq, Mar 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.932

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SLC52A3	NM_033409.4	c.1346C>G	p.Pro449Arg	missense_variant	5/5	ENST00000645534.1	NP_212134.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SLC52A3	ENST00000645534.1	c.1346C>G	p.Pro449Arg	missense_variant	5/5		NM_033409.4	ENSP00000494193.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000423 AC: 1 AN: 236322 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 129510

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000945

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000480 AC: 7 AN: 1457066 Hom.: 0 Cov.: 30 AF XY: 0.00000276 AC XY: 2 AN XY: 724594

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: 0.00000540

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 01, 2024

The c.1346C>G (p.P449R) alteration is located in exon 5 (coding exon 4) of the SLC52A3 gene. This alteration results from a C to G substitution at nucleotide position 1346, causing the proline (P) at amino acid position 449 to be replaced by an arginine (R). Based on data from gnomAD, the G allele has an overall frequency of <0.001% (1/236322) total alleles studied. The highest observed frequency was 0.001% (1/105830) of European (non-Finnish) alleles. This amino acid position is highly conserved in available vertebrate species. This alteration is predicted to be deleterious by in silico analysis. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Brown-Vialetto-van Laere syndrome 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 18, 2023

This sequence change replaces proline, which is neutral and non-polar, with arginine, which is basic and polar, at codon 449 of the SLC52A3 protein (p.Pro449Arg). 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 SLC52A3-related conditions. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt SLC52A3 protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.78
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.33
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Benign	0.29	T;T;T;T
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.91	.;.;.;D
M_CAP	Uncertain	0.21	D
MetaRNN	Pathogenic	0.93	D;D;D;D
MetaSVM	Uncertain	0.28	D
MutationAssessor	Pathogenic	3.3	M;M;M;M
PrimateAI	Uncertain	0.76	T
PROVEAN	Pathogenic	-8.2	.;.;D;.
REVEL	Pathogenic	0.76
Sift	Uncertain	0.0040	.;.;D;.
Sift4G	Uncertain	0.0060	.;D;D;.
Polyphen		1.0	D;D;D;D
Vest4		0.88
MutPred		0.79		Gain of methylation at P449 (P = 0.0247);Gain of methylation at P449 (P = 0.0247);Gain of methylation at P449 (P = 0.0247);Gain of methylation at P449 (P = 0.0247);
MVP		0.78
MPC		1.1
ClinPred		1.0	D
GERP RS		4.4
Varity_R		0.79
gMVP		0.85

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: rs1322154756; hg19: chr20-741734;