Genetic Variant ST8SIA1:p.Arg257Cys (chr12-22201854-G-A) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_003034.4(ST8SIA1):c.769C>T(p.Arg257Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000198 in 1,614,014 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

ST8SIA1
NM_003034.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 4.33

Publications

4 publications found

Variant links:

Genes affected

ST8SIA1 (HGNC:10869): (ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 1) Gangliosides are membrane-bound glycosphingolipids containing sialic acid. Ganglioside GD3 is known to be important for cell adhesion and growth of cultured malignant cells. The protein encoded by this gene is a type II membrane protein that catalyzes the transfer of sialic acid from CMP-sialic acid to GM3 to produce gangliosides GD3 and GT3. The encoded protein may be found in the Golgi apparatus and is a member of glycosyltransferase family 29. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Jan 2015]

ST8SIA1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ST8SIA1	NM_003034.4 link	c.769C>T	p.Arg257Cys	missense_variant	Exon 5 of 5	ENST00000396037.9	NP_003025.1	Q92185-1
ST8SIA1	NM_001304450.2 link	c.340C>T	p.Arg114Cys	missense_variant	Exon 4 of 4		NP_001291379.1	Q92185

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ST8SIA1	ENST00000396037.9 link	c.769C>T	p.Arg257Cys	missense_variant	Exon 5 of 5	1	NM_003034.4	ENSP00000379353.3		Q92185-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152224

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000279

AC:

AN:

250652

AF XY:

0.0000148

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.0000994

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000265

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000212

AC:

AN:

1461790

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

727196

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33466

American (AMR)

AF:

0.00

AC:

AN:

44708

Ashkenazi Jewish (ASJ)

AF:

0.0000383

AC:

AN:

26134

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39698

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000234

AC:

AN:

1111950

Other (OTH)

AF:

0.0000166

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.502

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152224

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74378

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41444

American (AMR)

AF:

0.0000654

AC:

AN:

15290

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5208

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68038

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000264

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Mar 02, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.769C>T (p.R257C) alteration is located in exon 5 (coding exon 5) of the ST8SIA1 gene. This alteration results from a C to T substitution at nucleotide position 769, causing the arginine (R) at amino acid position 257 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.48

BayesDel_addAF

Benign

-0.048

BayesDel_noAF

Benign

-0.14

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Benign

0.37

Eigen

Uncertain

0.64

Eigen_PC

Uncertain

0.56

FATHMM_MKL

Uncertain

0.95

LIST_S2

Uncertain

0.96

M_CAP

Benign

0.077

MetaRNN

Uncertain

0.68

MetaSVM

Benign

-0.48

MutationAssessor

Uncertain

2.2

PhyloP100

4.3

PrimateAI

Uncertain

0.70

PROVEAN

Uncertain

-4.0

REVEL

Uncertain

0.32

Sift

Uncertain

0.022

Sift4G

Uncertain

0.053

Polyphen

1.0

Vest4

0.55

MutPred

0.57

Loss of MoRF binding (P = 0.0065);

MVP

0.69

MPC

1.4

ClinPred

0.91

GERP RS

3.8

Varity_R

0.26

gMVP

0.82

Mutation Taster

=60/40

polymorphism

(source)

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

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12-22201854-G-A

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over