NM_198576.4:c.904G>T

Variant names:

• chr1-1041349-G-T
• rs1318084676
• NM_198576.4:c.904G>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_198576.4(AGRN):​c.904G>T​(p.Ala302Ser) variant causes a missense change. 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. A302G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: AGRN NM_198576.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.24
• Publications: 0 publications found

Genes affected

AGRN (HGNC:329): (agrin) This gene encodes one of several proteins that are critical in the development of the neuromuscular junction (NMJ), as identified in mouse knock-out studies. The encoded protein contains several laminin G, Kazal type serine protease inhibitor, and epidermal growth factor domains. Additional post-translational modifications occur to add glycosaminoglycans and disulfide bonds. In one family with congenital myasthenic syndrome affecting limb-girdle muscles, a mutation in this gene was found. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Mar 2015]

AGRN Gene-Disease associations (from GenCC):

• congenital myasthenic syndrome 8

  Inheritance: AR Classification: STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• presynaptic congenital myasthenic syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• postsynaptic congenital myasthenic syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

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

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_198576.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	AGRN	NM_198576.4	MANE Select	c.904G>T	p.Ala302Ser	missense	Exon 5 of 36	NP_940978.2
	AGRN	NM_001305275.2		c.904G>T	p.Ala302Ser	missense	Exon 5 of 39	NP_001292204.1
	AGRN	NM_001364727.2		c.589G>T	p.Ala197Ser	missense	Exon 4 of 36	NP_001351656.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	AGRN	ENST00000379370.7	TSL:1 MANE Select	c.904G>T	p.Ala302Ser	missense	Exon 5 of 36	ENSP00000368678.2
	AGRN	ENST00000651234.1		c.589G>T	p.Ala197Ser	missense	Exon 4 of 38	ENSP00000499046.1
	AGRN	ENST00000652369.2		c.589G>T	p.Ala197Ser	missense	Exon 4 of 35	ENSP00000498543.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1377006 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 679978

African (AFR) AF: 0.00 AC: 0 AN: 31032

American (AMR) AF: 0.00 AC: 0 AN: 33870

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 24298

East Asian (EAS) AF: 0.00 AC: 0 AN: 35924

South Asian (SAS) AF: 0.00 AC: 0 AN: 78338

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 33694

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5644

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1076798

Other (OTH) AF: 0.00 AC: 0 AN: 57408

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital myasthenic syndrome 8 Uncertain:1

Mar 29, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine with serine at codon 302 of the AGRN protein (p.Ala302Ser). The alanine residue is highly conserved and there is a moderate physicochemical difference between alanine and serine. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the ExAC database. This variant has not been reported in the literature in individuals with AGRN-related conditions. 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: "Possibly 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.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Benign	-0.12	T
BayesDel_noAF	Benign	-0.42
CADD	Uncertain	24
DANN	Uncertain	0.99
Eigen	Uncertain	0.39
Eigen_PC	Uncertain	0.30
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Benign	0.85	T
M_CAP	Uncertain	0.12	D
MetaRNN	Uncertain	0.61	D
MetaSVM	Benign	-1.2	T
MutationAssessor	Benign	1.8	L
PhyloP100		5.2
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-1.6	N
REVEL	Benign	0.25
Sift	Benign	0.11	T
Sift4G	Benign	0.091	T
Vest4		0.37
MutPred		0.56		Gain of phosphorylation at A302 (P = 0.0269)
MVP		0.66
MPC		1.0
ClinPred		0.93	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.9
gMVP		0.47
Mutation Taster		=70/30	polymorphism

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

Other links and lift over

dbSNP: rs1318084676; hg19: chr1-976729;