chr4-177434418-G-A

Variant names:

• chr4-177434418-G-A
• rs386833434
• NM_000027.4:c.770C>T

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP3_Strong PP5

The NM_000027.4(AGA):​c.770C>T​(p.Thr257Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,878 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 Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. T257T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: AGA NM_000027.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 9.49
• Publications: 1 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: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 12 uncertain in NM_000027.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989
• PP5: Variant 4-177434418-G-A is Pathogenic according to our data. Variant chr4-177434418-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 55953.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000027.4. 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
	AGA	NM_000027.4	MANE Select	c.770C>T	p.Thr257Ile	missense	Exon 7 of 9	NP_000018.2
	AGA	NM_001171988.2		c.740C>T	p.Thr247Ile	missense	Exon 7 of 9	NP_001165459.1
	AGA	NR_033655.2		n.756C>T		non_coding_transcript_exon	Exon 6 of 8

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	AGA	ENST00000264595.7	TSL:1 MANE Select	c.770C>T	p.Thr257Ile	missense	Exon 7 of 9	ENSP00000264595.2
	AGA	ENST00000926431.1		c.785C>T	p.Thr262Ile	missense	Exon 7 of 9	ENSP00000596490.1
	AGA	ENST00000502310.5	TSL:5	c.341C>T	p.Thr114Ile	missense	Exon 4 of 5	ENSP00000423798.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00000795 AC: 2 AN: 251474 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000462

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461878 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727240

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.0000374 AC: 2 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112002

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 31

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
2	1	-	Aspartylglucosaminuria (3)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.53
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.30	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.4	H
PhyloP100		9.5
PrimateAI	Uncertain	0.63	T
PROVEAN	Pathogenic	-5.7	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.91		Loss of disorder (P = 0.0506)
MVP		1.0
MPC		0.55
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.96
gMVP		0.99
Mutation Taster		=10/90	disease causing (ClinVar)

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: rs386833434; hg19: chr4-178355572;