rs587777216

Positions:

• chr11-125618475-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Moderate PP5_Moderate

The NM_152713.5(STT3A):​c.1877T>C​(p.Val626Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,870 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: 0.0000014 (0 hom.)
• Consequence: STT3A NM_152713.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 8.02

Genes affected

STT3A (HGNC:6172): (STT3 oligosaccharyltransferase complex catalytic subunit A) The protein encoded by this gene is a catalytic subunit of the N-oligosaccharyltransferase (OST) complex, which functions in the endoplasmic reticulum to transfer glycan chains to asparagine residues of target proteins. A separate complex containing a similar catalytic subunit with an overlapping function also exists. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Aug 2015]

STT3A (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), STT3A. . Gene score misZ 3.6202 (greater than the threshold 3.09). Trascript score misZ 4.4288 (greater than threshold 3.09). GenCC has associacion of gene with STT3A-congenital disorder of glycosylation, congenital disorder of glycosylation, type Iw, autosomal dominant.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.88
• PP5: Variant 11-125618475-T-C is Pathogenic according to our data. Variant chr11-125618475-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 102443.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr11-125618475-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
STT3A	NM_152713.5	c.1877T>C	p.Val626Ala	missense_variant	16/18	ENST00000392708.9	NP_689926.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
STT3A	ENST00000392708.9	c.1877T>C	p.Val626Ala	missense_variant	16/18	1	NM_152713.5	ENSP00000376472.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461870 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727236

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

STT3A-congenital disorder of glycosylation Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Nov 15, 2013

- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 19, 2024

This sequence change replaces valine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 626 of the STT3A protein (p.Val626Ala). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with congenital disorder of glycosylation (PMID: 23842455, 28424003). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 102443). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt STT3A protein function with a negative predictive value of 80%. Studies have shown that this missense change alters STT3A gene expression (PMID: 23842455). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.43	T;T;T;.
Eigen	Pathogenic	0.74
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	.;.;D;D
M_CAP	Pathogenic	0.51	D
MetaRNN	Pathogenic	0.88	D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.4	M;M;M;.
PrimateAI	Pathogenic	0.88	D
PROVEAN	Uncertain	-3.3	D;D;.;D
REVEL	Pathogenic	0.95
Sift	Uncertain	0.021	D;D;.;D
Sift4G	Uncertain	0.024	D;D;.;D
Polyphen		0.97	D;D;D;.
Vest4		0.84
MutPred		0.59		Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);.;
MVP		0.85
MPC		1.7
ClinPred		0.97	D
GERP RS		5.1
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.0
Varity_R		0.64
gMVP		0.85

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: rs587777216; hg19: chr11-125488370;