4-177431756-A-C

Variant names:

• chr4-177431756-A-C
• rs1201784742
• NM_000027.4:c.993T>G

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PVS1_Moderate PM2 PP5

The NM_000027.4(AGA):​c.993T>G​(p.Tyr331*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: AGA NM_000027.4 stop_gained
• Clinical Significance: Likely pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 0.425
• Publications: 0 publications found

Genes affected

AGA (HGNC:318): (aspartylglucosaminidase) This gene encodes a member of the N-terminal nucleophile (Ntn) hydrolase family of proteins. The encoded preproprotein is proteolytically processed to generate alpha and beta chains that comprise the mature enzyme. This enzyme is involved in the catabolism of N-linked oligosaccharides of glycoproteins. It cleaves asparagine from N-acetylglucosamines as one of the final steps in the lysosomal breakdown of glycoproteins. Mutations in this gene are associated with the lysosomal storage disease aspartylglycosaminuria that results in progressive neurodegeneration. Alternative splicing results in multiple transcript variants, at least one of which encodes an isoform that is subject to proteolytic processing. [provided by RefSeq, Nov 2015]

AGA Gene-Disease associations (from GenCC):

• aspartylglucosaminuria

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, G2P, Orphanet, Myriad Women’s Health, Labcorp Genetics (formerly Invitae), Genomics England PanelApp

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0461 CDS is truncated, and there are 2 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-177431756-A-C is Pathogenic according to our data. Variant chr4-177431756-A-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 552400.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
AGA	NM_000027.4	c.993T>G	p.Tyr331*	stop_gained	Exon 9 of 9	ENST00000264595.7	NP_000018.2
AGA	NM_001171988.2	c.963T>G	p.Tyr321*	stop_gained	Exon 9 of 9		NP_001165459.1
AGA	NR_033655.2	n.979T>G		non_coding_transcript_exon_variant	Exon 8 of 8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
AGA	ENST00000264595.7	c.993T>G	p.Tyr331*	stop_gained	Exon 9 of 9	1	NM_000027.4	ENSP00000264595.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Aspartylglucosaminuria Pathogenic:1

Jun 21, 2017

Counsyl

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	36
DANN	Uncertain	0.99
Eigen	Uncertain	0.28
Eigen_PC	Benign	0.10
FATHMM_MKL	Uncertain	0.90	D
PhyloP100		0.42
Vest4		0.80
GERP RS		0.74
Mutation Taster		=17/183	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.21		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.21		Position offset: -1

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

Other links and lift over

dbSNP: rs1201784742; hg19: chr4-178352910;