rs755213977

Positions:

• chrX-111736778-C-T

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_Moderate BS2

The NM_001099922.3(ALG13):​c.2594C>T​(p.Ser865Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000638 in 1,097,104 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 5 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. 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. S865P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000064 (0 hom. 5 hem.)
• Consequence: ALG13 NM_001099922.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 2.79

Genes affected

ALG13 (HGNC:30881): (ALG13 UDP-N-acetylglucosaminyltransferase subunit) The protein encoded by this gene is a subunit of a bipartite UDP-N-acetylglucosamine transferase. It heterodimerizes with asparagine-linked glycosylation 14 homolog to form a functional UDP-GlcNAc glycosyltransferase that catalyzes the second sugar addition of the highly conserved oligosaccharide precursor in endoplasmic reticulum N-linked glycosylation. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Dec 2009]

ACMG classification

Verdict is Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.20592844).
• BS2: High Hemizygotes in GnomAdExome4 at 5 XL gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ALG13	NM_001099922.3	c.2594C>T	p.Ser865Phe	missense_variant	23/27	ENST00000394780.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALG13	ENST00000394780.8	c.2594C>T	p.Ser865Phe	missense_variant	23/27	2	NM_001099922.3	A2

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 0.00000638 AC: 7 AN: 1097104 Hom.: 0 Cov.: 29 AF XY: 0.0000138 AC XY: 5 AN XY: 362606

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: 0.00000832

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.00000830 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Developmental and epileptic encephalopathy, 36 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 02, 2022

This sequence change replaces serine, which is neutral and polar, with phenylalanine, which is neutral and non-polar, at codon 865 of the ALG13 protein (p.Ser865Phe). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with ALG13-related conditions. ClinVar contains an entry for this variant (Variation ID: 581060). 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 ALG13 protein function. 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Sep 13, 2024

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Benign	-0.16	T
BayesDel_noAF	Benign	-0.47
CADD	Benign	17
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.69	D;.;.;.;.
FATHMM_MKL	Benign	0.33	N
LIST_S2	Benign	0.75	T;T;.;T;.
M_CAP	Pathogenic	0.40	D
MetaRNN	Benign	0.21	T;T;T;T;T
MetaSVM	Benign	-0.82	T
MutationAssessor	Benign	1.4	L;.;.;.;.
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.29	T
PROVEAN	Uncertain	-2.6	D;.;D;.;.
REVEL	Benign	0.12
Sift	Uncertain	0.013	D;.;D;.;.
Sift4G	Uncertain	0.020	D;D;D;D;D
Polyphen		0.50	P;P;P;P;P
Vest4		0.29
MutPred		0.40		Gain of catalytic residue at S865 (P = 0.002);.;.;.;.;
MVP		0.42
MPC		0.40
ClinPred		0.70	D
GERP RS		3.7
Varity_R		0.14
gMVP		0.32

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs755213977; hg19: chrX-110980006;