5-134607045-G-T

Variant names:

• chr5-134607045-G-T
• rs1175873618
• NM_016103.4:c.502C>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM1 PM2 PP2 BP4

The NM_016103.4(SAR1B):​c.502C>A​(p.Leu168Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,460,934 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. L168L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: SAR1B NM_016103.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.91
• Publications: 0 publications found

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]

SAR1B Gene-Disease associations (from GenCC):

• chylomicron retention disease

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, PanelApp Australia

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a chain Small COPII coat GTPase SAR1B (size 197) in uniprot entity SAR1B_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_016103.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 3 curated pathogenic missense variants (we use a threshold of 10). The gene has 0 curated benign missense variants. Gene score misZ: 0.81398 (below the threshold of 3.09). Trascript score misZ: 1.3781 (below the threshold of 3.09). GenCC associations: The gene is linked to chylomicron retention disease.
• BP4: Computational evidence support a benign effect (MetaRNN=0.3093726).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_016103.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SAR1B	NM_016103.4	MANE Select	c.502C>A	p.Leu168Met	missense	Exon 7 of 7	NP_057187.1	Q9Y6B6
	SAR1B	NM_001033503.3		c.502C>A	p.Leu168Met	missense	Exon 8 of 8	NP_001028675.1	Q9Y6B6

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SAR1B	ENST00000402673.7	TSL:1 MANE Select	c.502C>A	p.Leu168Met	missense	Exon 7 of 7	ENSP00000385432.2	Q9Y6B6
	SAR1B	ENST00000439578.5	TSL:1	c.502C>A	p.Leu168Met	missense	Exon 8 of 8	ENSP00000404997.1	Q9Y6B6
	SAR1B	ENST00000507419.5	TSL:1	c.298C>A	p.Leu100Met	missense	Exon 7 of 7	ENSP00000425339.1	Q9H029

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251246 AF XY: 0.00000737

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1460934 Hom.: 0 Cov.: 29 AF XY: 0.00000138 AC XY: 1 AN XY: 726828

African (AFR) AF: 0.00 AC: 0 AN: 33460

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26124

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111156

Other (OTH) AF: 0.00 AC: 0 AN: 60362

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.092
BayesDel_addAF	Uncertain	0.018	T
BayesDel_noAF	Benign	-0.21
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.16	T
Eigen	Benign	-0.11
Eigen_PC	Benign	0.030
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.84	T
M_CAP	Benign	0.058	D
MetaRNN	Benign	0.31	T
MetaSVM	Uncertain	-0.23	T
MutationAssessor	Uncertain	2.2	M
PhyloP100		2.9
PrimateAI	Pathogenic	0.80	T
PROVEAN	Benign	-1.0	N
REVEL	Uncertain	0.33
Sift	Benign	0.14	T
Sift4G	Benign	0.13	T
Polyphen		0.16	B
Vest4		0.44
MutPred		0.46		Loss of catalytic residue at L168 (P = 0.0474)
MVP		0.81
MPC		0.36
ClinPred		0.18	T
GERP RS		4.0
Varity_R		0.33
gMVP		0.28
Mutation Taster		=70/30	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1175873618; hg19: chr5-133942735;