rs1330914046

Positions:

• chr8-144359811-G-A
• chr8-144359811-G-C

Variant summary

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

The NM_001363118.2(SLC52A2):​c.319G>A​(p.Gly107Arg) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. G107G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: SLC52A2 NM_001363118.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.73

Genes affected

SLC52A2 (HGNC:30224): (solute carrier family 52 member 2) This gene encodes a membrane protein which belongs to the riboflavin transporter family. In humans, riboflavin must be obtained by intestinal absorption because it cannot be synthesized by the body. The water-soluble vitamin riboflavin is processed to the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) which then act as intermediaries in many cellular metabolic reactions. Paralogous members of the riboflavin transporter gene family are located on chromosomes 17 and 20. Unlike other members of this family, this gene has higher expression in brain tissue than small intestine. Alternative splicing of this gene results in multiple transcript variants encoding the same protein. Mutations in this gene have been associated with Brown-Vialetto-Van Laere syndrome 2 - an autosomal recessive progressive neurologic disorder characterized by deafness, bulbar dysfunction, and axial and limb hypotonia. [provided by RefSeq, Jul 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, 0.928

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SLC52A2	NM_001363118.2	c.319G>A	p.Gly107Arg	missense_variant	3/5	ENST00000643944.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SLC52A2	ENST00000643944.2	c.319G>A	p.Gly107Arg	missense_variant	3/5		NM_001363118.2	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Brown-Vialetto-van Laere syndrome 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 30, 2017

This sequence change replaces glycine with arginine at codon 107 of the SLC52A2 protein (p.Gly107Arg). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and arginine. This variant is not present in population databases (ExAC no frequency). 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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with SLC52A2-related disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Uncertain	23
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.71	D;D;D;T;D;D;D
Eigen	Benign	0.079
Eigen_PC	Benign	-0.098
FATHMM_MKL	Uncertain	0.91	D
M_CAP	Pathogenic	0.76	D
MetaRNN	Pathogenic	0.93	D;D;D;D;D;D;D
MetaSVM	Uncertain	0.52	D
MutationAssessor	Pathogenic	3.1	M;M;M;.;M;M;M
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.55	T
PROVEAN	Pathogenic	-6.7	D;D;D;D;D;D;.
REVEL	Pathogenic	0.65
Sift	Uncertain	0.029	D;D;D;D;D;D;.
Sift4G	Uncertain	0.042	D;D;D;D;D;D;.
Polyphen		1.0	D;D;D;.;D;D;D
Vest4		0.46
MutPred		0.66		Gain of solvent accessibility (P = 0.0037);Gain of solvent accessibility (P = 0.0037);Gain of solvent accessibility (P = 0.0037);Gain of solvent accessibility (P = 0.0037);Gain of solvent accessibility (P = 0.0037);Gain of solvent accessibility (P = 0.0037);Gain of solvent accessibility (P = 0.0037);
MVP		0.65
MPC		0.51
ClinPred		1.0	D
GERP RS		2.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.14
gMVP		0.83

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1330914046; hg19: chr8-145583471;