9-99218008-T-C

Variant names:

• chr9-99218008-T-C
• rs963221673
• NM_033087.4:c.1177A>G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_033087.4(ALG2):​c.1177A>G​(p.Arg393Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 152,244 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 Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.000013 (0 hom., cov: 33)
• Consequence: ALG2 NM_033087.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.01

Genes affected

ALG2 (HGNC:23159): (ALG2 alpha-1,3/1,6-mannosyltransferase) This gene encodes a member of the glycosyltransferase 1 family. The encoded protein acts as an alpha 1,3 mannosyltransferase, mannosylating Man(2)GlcNAc(2)-dolichol diphosphate and Man(1)GlcNAc(2)-dolichol diphosphate to form Man(3)GlcNAc(2)-dolichol diphosphate. Defects in this gene have been associated with congenital disorder of glycosylation type Ih (CDG-Ii). Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.912

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ALG2	NM_033087.4	c.1177A>G	p.Arg393Gly	missense_variant	Exon 2 of 2	ENST00000476832.2	NP_149078.1
ALG2	XM_047423996.1	c.898A>G	p.Arg300Gly	missense_variant	Exon 2 of 2		XP_047279952.1
ALG2	NR_024532.2	n.1384A>G		non_coding_transcript_exon_variant	Exon 3 of 3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ALG2	ENST00000476832.2	c.1177A>G	p.Arg393Gly	missense_variant	Exon 2 of 2	1	NM_033087.4	ENSP00000417764.1
ALG2	ENST00000319033.7	c.898A>G	p.Arg300Gly	missense_variant	Exon 2 of 2	1		ENSP00000326609.6
ALG2	ENST00000238477.5	n.*919A>G		non_coding_transcript_exon_variant	Exon 3 of 3	2		ENSP00000432675.2
ALG2	ENST00000238477.5	n.*919A>G		3_prime_UTR_variant	Exon 3 of 3	2		ENSP00000432675.2

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152244 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000482

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152244 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74384

Gnomad4 AFR AF: 0.0000482

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

ALG2-congenital disorder of glycosylation;C4015597:Congenital myasthenic syndrome 14 Uncertain:1

Feb 08, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. 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: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C15"). ClinVar contains an entry for this variant (Variation ID: 566269). This variant has not been reported in the literature in individuals affected with ALG2-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.01%). This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 393 of the ALG2 protein (p.Arg393Gly). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.59
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.21
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.68	D;.
Eigen	Pathogenic	0.69
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Uncertain	0.93	D;D
M_CAP	Pathogenic	0.59	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Uncertain	0.54	D
MutationAssessor	Pathogenic	3.9	H;.
PrimateAI	Benign	0.46	T
PROVEAN	Pathogenic	-5.3	D;D
REVEL	Pathogenic	0.87
Sift	Uncertain	0.013	D;D
Sift4G	Uncertain	0.013	D;D
Polyphen		1.0	D;D
Vest4		0.87
MutPred		0.67		Loss of MoRF binding (P = 0.023);.;
MVP		0.93
MPC		0.84
ClinPred		0.99	D
GERP RS		3.5
Varity_R		0.91
gMVP		0.87

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: rs963221673; hg19: chr9-101980290;