rs782498327

Positions:

• chr8-144359830-CCTT-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PM4_Supporting

The NM_001363118.2(SLC52A2):​c.342_344delCTT​(p.Phe114del) variant causes a disruptive inframe deletion change. The variant allele was found at a frequency of 0.0000171 in 1,461,338 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000017 (0 hom.)
• Consequence: SLC52A2 NM_001363118.2 disruptive_inframe_deletion
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 4.96

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]

SLC52A2 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Nonframeshift variant in NON repetitive region in NM_001363118.2. Strenght limited to Supporting due to length of the change: 1aa.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SLC52A2	NM_001363118.2	c.342_344delCTT	p.Phe114del	disruptive_inframe_deletion	3/5	ENST00000643944.2	NP_001350047.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SLC52A2	ENST00000643944.2	c.342_344delCTT	p.Phe114del	disruptive_inframe_deletion	3/5		NM_001363118.2	ENSP00000496184.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 250972 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135718

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: 0.00000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000171 AC: 25 AN: 1461338 Hom.: 0 AF XY: 0.0000179 AC XY: 13 AN XY: 726964

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: 0.0000225

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Brown-Vialetto-van Laere syndrome 2 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	May 21, 2020	A heterozygous in-frame deletion variant was identified, NM_001253816.1(SLC52A2):c.342_344del in exon 3 of 5 of the SLC52A2 gene. This variant is predicted to result in an in-frame deletion of a single amino acid at position 114 of the protein; NP_001240745.1(SLC52A2):p.(Phe114del). The phenylalanine at this position has high conservation (100 vertebrates, UCSC), and is not situated in a known functional domain. The variant is present in the gnomAD population database at a frequency of 0.0004% (1 heterozygotes, 0 homozygotes). The variant has previously been reported once as VUS (ClinVar). Based on information available at the time of curation, this variant has been classified as a VUS. -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 26, 2022	This variant is present in population databases (rs782498327, gnomAD 0.0009%). 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. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. ClinVar contains an entry for this variant (Variation ID: 540429). This variant has not been reported in the literature in individuals affected with SLC52A2-related conditions. This variant, c.342_344del, results in the deletion of 1 amino acid(s) of the SLC52A2 protein (p.Phe114del), but otherwise preserves the integrity of the reading frame. -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 02, 2022

The c.342_344delCTT variant (also known as p.F114del) is located in coding exon 2 of the SLC52A2 gene. This variant results from an in-frame CTT deletion at nucleotide positions 342 to 344. This results in the in-frame deletion of a phenylalanine at codon 114. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis (Choi Y et al. PLoS ONE. 2012; 7(10):e46688). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

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: rs782498327; hg19: chr8-145583490;