1-43736345-G-A

Variant names:

• chr1-43736345-G-A
• NM_006279.5:c.83G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_006279.5(ST3GAL3):​c.83G>A​(p.Trp28*) variant causes a stop gained change. The variant allele was found at a frequency of 0.000000684 in 1,461,882 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ST3GAL3 NM_006279.5 stop_gained
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 4.88
• Publications: 0 publications found

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]

ST3GAL3 Gene-Disease associations (from GenCC):

• developmental and epileptic encephalopathy, 15

  Inheritance: AR Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• intellectual disability, autosomal recessive 12

  Inheritance: AR Classification: STRONG Submitted by: G2P
• complex neurodevelopmental disorder

  Inheritance: AR Classification: MODERATE Submitted by: ClinGen
• infantile spasms

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• autosomal recessive non-syndromic intellectual disability

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000284989 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 11 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-43736345-G-A is Pathogenic according to our data. Variant chr1-43736345-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3898041.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ST3GAL3	NM_006279.5	c.83G>A	p.Trp28*	stop_gained	Exon 2 of 12	ENST00000347631.8	NP_006270.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ST3GAL3	ENST00000347631.8	c.83G>A	p.Trp28*	stop_gained	Exon 2 of 12	5	NM_006279.5	ENSP00000317192.6
ENSG00000284989	ENST00000645057.1	n.*1405G>A		non_coding_transcript_exon_variant	Exon 16 of 26			ENSP00000494063.1
ENSG00000284989	ENST00000645057.1	n.*1405G>A		3_prime_UTR_variant	Exon 16 of 26			ENSP00000494063.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461882 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727238

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112004

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy, 15 Pathogenic:1

Feb 01, 2024

Neuberg Centre For Genomic Medicine, NCGM

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The stop gained variant c.83G>A (p.Trp28Ter) in the ST3GAL3 gene has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. Loss of function variants has been previously reported to be disease causing (Indellicato et al., 2020). For these reasons, this variant has been classified as Likely Pathogenic -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.61	D
BayesDel_noAF	Pathogenic	0.63
CADD	Pathogenic	40
DANN	Uncertain	0.99
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Uncertain	0.94	D
PhyloP100		4.9
Vest4		0.47
GERP RS		5.9
PromoterAI		-0.010	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=6/194	disease causing (fs/PTC)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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

hg19: chr1-44202016;