1-1050334-G-C

Position:

• chr1-1050334-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_198576.4(AGRN):​c.4976+5G>C variant causes a splice region, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: AGRN NM_198576.4 splice_region, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.71

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
AGRN	NM_198576.4	c.4976+5G>C		splice_region_variant, intron_variant		ENST00000379370.7	NP_940978.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
AGRN	ENST00000379370.7	c.4976+5G>C		splice_region_variant, intron_variant		1	NM_198576.4	ENSP00000368678.2
AGRN	ENST00000651234.1	c.4661+5G>C		splice_region_variant, intron_variant				ENSP00000499046.1
AGRN	ENST00000652369.1	c.4661+5G>C		splice_region_variant, intron_variant				ENSP00000498543.1
AGRN	ENST00000620552.4	c.4562+5G>C		splice_region_variant, intron_variant		5		ENSP00000484607.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital myasthenic syndrome 8 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 11, 2017

This sequence change falls in intron 28 of the AGRN gene. It does not directly change the encoded amino acid sequence of the AGRN protein, but it affects a nucleotide within the consensus splice site of the intron. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with AGRN-related disease. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. 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 v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.50
CADD	Benign	22
DANN	Benign	0.83
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.49		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.49		Position offset: -5

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

Publications

LitVar

Other links and lift over

dbSNP: rs1553177963; hg19: chr1-985714;