1-43920482-T-C

Position:

• chr1-43920482-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_006279.5(ST3GAL3):​c.823T>C​(p.Tyr275His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y275C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ST3GAL3 NM_006279.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.54

Genes affected

ST3GAL3 (HGNC:10866): (ST3 beta-galactoside alpha-2,3-sialyltransferase 3) The protein encoded by this gene is a type II membrane protein that catalyzes the transfer of sialic acid from CMP-sialic acid to galactose-containing substrates. The encoded protein is normally found in the Golgi apparatus but can be proteolytically processed to a soluble form. This protein is a member of glycosyltransferase family 29. Mutations in this gene have been associated with a form of autosomal recessive nonsymdromic cognitive disability as well as infantile epileptic encephalopathy. Multiple transcript variants encoding several different isoforms have been found for this gene. [provided by RefSeq, Jul 2017]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ST3GAL3	NM_006279.5	c.823T>C	p.Tyr275His	missense_variant	10/12	ENST00000347631.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ST3GAL3	ENST00000347631.8	c.823T>C	p.Tyr275His	missense_variant	10/12	5	NM_006279.5	A1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 08, 2022

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: "Probably 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. ClinVar contains an entry for this variant (Variation ID: 530539). This variant has not been reported in the literature in individuals affected with ST3GAL3-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces tyrosine, which is neutral and polar, with histidine, which is basic and polar, at codon 275 of the ST3GAL3 protein (p.Tyr275His). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.67
BayesDel_addAF	Uncertain	0.058	T
BayesDel_noAF	Benign	-0.15
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Benign	0.14	T;.;.;.;.;.;.;.;T;.;.;.;.;T;.;.;.
Eigen	Uncertain	0.51
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.95	.;D;D;D;D;D;D;D;.;D;D;D;D;D;D;D;D
M_CAP	Benign	0.019	T
MetaRNN	Uncertain	0.50	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.99	T
MutationAssessor	Benign	2.0	M;.;.;.;.;.;.;.;M;.;.;.;.;M;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
PrimateAI	Pathogenic	0.82	D
PROVEAN	Benign	-1.4	.;N;N;N;.;.;.;.;.;.;N;.;.;.;N;.;.
REVEL	Benign	0.23
Sift	Benign	0.21	.;T;T;T;.;.;.;.;.;.;T;.;.;.;T;.;.
Sift4G	Benign	0.45	.;T;T;T;.;.;.;.;.;.;T;.;.;.;T;.;.
Polyphen		1.0	D;D;D;D;.;.;D;D;D;.;D;.;.;D;.;.;.
Vest4		0.79, 0.84, 0.84, 0.85, 0.83
MutPred		0.51		Loss of catalytic residue at Y275 (P = 0.0276);.;.;.;Loss of catalytic residue at Y275 (P = 0.0276);.;.;.;Loss of catalytic residue at Y275 (P = 0.0276);Loss of catalytic residue at Y275 (P = 0.0276);.;.;Loss of catalytic residue at Y275 (P = 0.0276);Loss of catalytic residue at Y275 (P = 0.0276);.;.;.;
MVP		0.31
MPC		1.7
ClinPred		0.95	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.21
gMVP		0.77

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: rs1553140040; hg19: chr1-44386154;