5-134606970-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 4P and 4B. PM1 PM2 BP4_Strong

The NM_016103.4(SAR1B):c.577A>C(p.Met193Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000124 in 1,613,014 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000033 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: SAR1B NM_016103.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.57

Genes affected

SAR1B (HGNC:10535): (secretion associated Ras related GTPase 1B) The protein encoded by this gene is a small GTPase that acts as a homodimer. The encoded protein is activated by the guanine nucleotide exchange factor PREB and is involved in protein transport from the endoplasmic reticulum to the Golgi. This protein is part of the COPII coat complex. Defects in this gene are a cause of chylomicron retention disease (CMRD), also known as Anderson disease (ANDD). Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Mar 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM1: In a chain GTP-binding protein SAR1b (size 197) in uniprot entity SAR1B_HUMAN there are 15 pathogenic changes around while only 1 benign (94%) in NM_016103.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.021360248).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SAR1B	NM_016103.4	c.577A>C	p.Met193Leu	missense_variant	7/7	ENST00000402673.7
SAR1B	NM_001033503.3	c.577A>C	p.Met193Leu	missense_variant	8/8
SAR1B	XM_047417257.1	c.577A>C	p.Met193Leu	missense_variant	7/7
SAR1B	XM_047417258.1	c.373A>C	p.Met125Leu	missense_variant	5/5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SAR1B	ENST00000402673.7	c.577A>C	p.Met193Leu	missense_variant	7/7	1	NM_016103.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000329 AC: 5 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: 0.000577

Gnomad SAS AF: 0.000414

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000676 AC: 17 AN: 251466 Hom.: 0 AF XY: 0.0000368 AC XY: 5 AN XY: 135898

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000761

Gnomad SAS exome AF: 0.0000980

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000103 AC: 15 AN: 1460690 Hom.: 0 Cov.: 29 AF XY: 0.0000110 AC XY: 8 AN XY: 726768

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000328

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000328 AC: 5 AN: 152324 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74486

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000578

Gnomad4 SAS AF: 0.000414

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000189

ExAC AF: 0.0000494 AC: 6

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 27, 2022

This sequence change replaces methionine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 193 of the SAR1B protein (p.Met193Leu). This variant is present in population databases (rs537197531, gnomAD 0.07%). This variant has not been reported in the literature in individuals affected with SAR1B-related conditions. ClinVar contains an entry for this variant (Variation ID: 1473582). 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 leucine 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.089
BayesDel_addAF	Benign	-0.34	T
BayesDel_noAF	Benign	-0.35
Cadd	Benign	14
Dann	Benign	0.62
DEOGEN2	Benign	0.12	T;.;.;T;.
Eigen	Benign	-0.81
Eigen_PC	Benign	-0.47
FATHMM_MKL	Uncertain	0.88	D
M_CAP	Benign	0.0063	T
MetaRNN	Benign	0.021	T;T;T;T;T
MetaSVM	Benign	-0.93	T
MutationAssessor	Benign	-2.1	N;.;.;N;.
MutationTaster	Benign	0.96	D;D;D;D;D
PrimateAI	Uncertain	0.59	T
PROVEAN	Benign	1.1	N;N;N;N;N
REVEL	Benign	0.14
Sift	Benign	1.0	T;T;T;T;T
Sift4G	Benign	1.0	T;T;T;T;T
Polyphen		0.0	B;.;.;B;.
Vest4		0.27
MutPred		0.63		Loss of MoRF binding (P = 0.0726);.;.;Loss of MoRF binding (P = 0.0726);.;
MVP		0.36
MPC		0.20
ClinPred		0.022	T
GERP RS		3.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.081
gMVP		0.62

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: rs537197531; hg19: chr5-133942660;