4-76161717-G-T

Position:

• chr4-76161717-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_005506.4(SCARB2):​c.1433C>A​(p.Thr478Asn) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SCARB2 NM_005506.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.79

Genes affected

SCARB2 (HGNC:1665): (scavenger receptor class B member 2) The protein encoded by this gene is a type III glycoprotein that is located primarily in limiting membranes of lysosomes and endosomes. Earlier studies in mice and rat suggested that this protein may participate in membrane transportation and the reorganization of endosomal/lysosomal compartment. The protein deficiency in mice was reported to impair cell membrane transport processes and cause pelvic junction obstruction, deafness, and peripheral neuropathy. Further studies in human showed that this protein is a ubiquitously expressed protein and that it is involved in the pathogenesis of HFMD (hand, foot, and mouth disease) caused by enterovirus-71 and possibly by coxsackievirus A16. Mutations in this gene caused an autosomal recessive progressive myoclonic epilepsy-4 (EPM4), also known as action myoclonus-renal failure syndrome (AMRF). Alternatively spliced transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Feb 2011]

(HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a mutagenesis_site Normal targeting of the protein to lysosomes. (size 0) in uniprot entity SCRB2_HUMAN
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.3062665).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SCARB2	NM_005506.4	c.1433C>A	p.Thr478Asn	missense_variant	12/12	ENST00000264896.8	NP_005497.1
SCARB2	NM_001204255.2	c.1004C>A	p.Thr335Asn	missense_variant	9/9		NP_001191184.1
SCARB2	XM_047416429.1	c.959C>A	p.Thr320Asn	missense_variant	12/12		XP_047272385.1
SCARB2	XM_047416430.1	c.959C>A	p.Thr320Asn	missense_variant	12/12		XP_047272386.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SCARB2	ENST00000264896.8	c.1433C>A	p.Thr478Asn	missense_variant	12/12	1	NM_005506.4	ENSP00000264896	P4
	ENST00000651366.1	n.102+12451G>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Progressive myoclonic epilepsy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 27, 2021

This sequence change replaces threonine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 478 of the SCARB2 protein (p.Thr478Asn). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SCARB2-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). 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	Benign	0.27
BayesDel_addAF	Uncertain	0.081	D
BayesDel_noAF	Benign	-0.12
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Benign	0.25	T;.;.;.;.;.
Eigen	Uncertain	0.25
Eigen_PC	Uncertain	0.22
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.89	D;D;D;D;D;D
M_CAP	Benign	0.057	D
MetaRNN	Benign	0.31	T;T;T;T;T;T
MetaSVM	Uncertain	-0.014	T
MutationAssessor	Benign	2.0	M;.;.;.;.;.
MutationTaster	Benign	0.99	N;N
PrimateAI	Uncertain	0.70	T
PROVEAN	Benign	-1.1	N;.;.;.;.;N
REVEL	Benign	0.28
Sift	Uncertain	0.0080	D;.;.;.;.;D
Sift4G	Pathogenic	0.0	D;.;.;.;.;D
Polyphen		0.99	D;.;.;.;.;.
Vest4		0.31
MutPred		0.28		Loss of glycosylation at T478 (P = 0.0528);.;.;.;.;.;
MVP		0.81
MPC		0.84
ClinPred		0.80	D
GERP RS		4.4
Varity_R		0.094
gMVP		0.42

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr4-77082870;