20-761103-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 6P and 2B. PM1 PM2 PM5 BP4_Moderate

The NM_033409.4(SLC52A3):c.1333C>G(p.Leu445Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000373 in 1,606,644 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L445P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: SLC52A3 NM_033409.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.274

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.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_033409.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr20-761102-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 429375.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP4: Computational evidence support a benign effect (MetaRNN=0.09550598).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SLC52A3	NM_033409.4	c.1333C>G	p.Leu445Val	missense_variant	5/5	ENST00000645534.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SLC52A3	ENST00000645534.1	c.1333C>G	p.Leu445Val	missense_variant	5/5		NM_033409.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152250 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000723

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1454394 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 723068

Gnomad4 AFR exome AF: 0.0000601

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: 9.01e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152250 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74380

Gnomad4 AFR AF: 0.0000723

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Brown-Vialetto-van Laere syndrome 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 19, 2022

Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The valine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect 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. ClinVar contains an entry for this variant (Variation ID: 1383680). This variant has not been reported in the literature in individuals affected with SLC52A3-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.01%). This sequence change replaces leucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 445 of the SLC52A3 protein (p.Leu445Val). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.068
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.43
Cadd	Benign	12
Dann	Benign	0.91
DEOGEN2	Benign	0.0076	T;T;T;T
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.0
FATHMM_MKL	Benign	0.45	N
M_CAP	Benign	0.013	T
MetaRNN	Benign	0.096	T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.53	N;N;N;N
MutationTaster	Benign	1.0	D;N
PrimateAI	Benign	0.42	T
Polyphen		0.0080	B;B;B;B
Vest4		0.089, 0.090
MutPred		0.27		Gain of catalytic residue at L445 (P = 0.0311);Gain of catalytic residue at L445 (P = 0.0311);Gain of catalytic residue at L445 (P = 0.0311);Gain of catalytic residue at L445 (P = 0.0311);
MVP		0.36
MPC		0.32
ClinPred		0.044	T
GERP RS		-2.1
Varity_R		0.062
gMVP		0.33

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: rs1431510759; hg19: chr20-741747;