14-75639383-CTG-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_017791.3(FLVCR2):c.1157_1158del(p.Leu386ArgfsTer38) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,782 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: FLVCR2 NM_017791.3 frameshift
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.91

Genes affected

FLVCR2 (HGNC:20105): (FLVCR choline and putative heme transporter 2) This gene encodes a member of the major facilitator superfamily. The encoded transmembrane protein is a calcium transporter. Unlike the related protein feline leukemia virus subgroup C receptor 1, the protein encoded by this locus does not bind to feline leukemia virus subgroup C envelope protein. The encoded protein may play a role in development of brain vascular endothelial cells, as mutations at this locus have been associated with proliferative vasculopathy and hydranencephaly-hydrocephaly syndrome. Alternatively spliced transcript variants have been described.[provided by RefSeq, Aug 2010]

TTLL5 (HGNC:19963): (tubulin tyrosine ligase like 5) This gene encodes a member of the tubulin tyrosine ligase like protein family. This protein interacts with two glucocorticoid receptor coactivators, transcriptional intermediary factor 2 and steroid receptor coactivator 1. This protein may function as a coregulator of glucocorticoid receptor mediated gene induction and repression. This protein may also function as an alpha tubulin polyglutamylase.[provided by RefSeq, Feb 2010]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FLVCR2	NM_017791.3	c.1157_1158del	p.Leu386ArgfsTer38	frameshift_variant	6/10	ENST00000238667.9
FLVCR2	NM_001195283.2	c.542_543del	p.Leu181ArgfsTer38	frameshift_variant	6/10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FLVCR2	ENST00000238667.9	c.1157_1158del	p.Leu386ArgfsTer38	frameshift_variant	6/10	1	NM_017791.3	P1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152206 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251384 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135852

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461576 Hom.: 0 AF XY: 0.00000138 AC XY: 1 AN XY: 727112

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152206 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74356

Gnomad4 AFR AF: 0.00

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: 0.0000294

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Posterior column ataxia-retinitis pigmentosa syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Aug 25, 2017

This variant results in a frameshift and is predicted to result in premature termination of the protein. It was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018) and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score for this variant, it could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene and cDNA change, and amino acid change. No publications were found based on this search. Due to the potential impact of frameshift variants and the lack of clarifying evidence, this variant is classified as a variant of unknown significance but suspicious for pathogenicity for this disease. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.10		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: rs779784201; hg19: chr14-76105726;