20-45897769-T-A

Variant names:

• chr20-45897769-T-A
• rs137854548
• NM_000308.4:c.1217T>A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PM5 PP3_Moderate

The NM_000308.4(CTSA):​c.1217T>A​(p.Met406Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000658 in 151,960 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M406T) has been classified as Pathogenic.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: CTSA NM_000308.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.71
• Publications: 4 publications found

Genes affected

CTSA (HGNC:9251): (cathepsin A) This gene encodes a member of the peptidase S10 family of serine carboxypeptidases. Alternative splicing results in multiple transcript variants, at least one of which encodes a preproprotein that is proteolytically processed to generate two chains that comprise the heterodimeric active enzyme. This enzyme possesses deamidase, esterase and carboxypeptidase activities and acts as a scaffold in the lysosomal multienzyme complex. Mutations in this gene are associated with galactosialidosis. [provided by RefSeq, Nov 2015]

CTSA Gene-Disease associations (from GenCC):

• galactosialidosis

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), Orphanet, Genomics England PanelApp, Illumina, G2P

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr20-45897769-T-C is described in ClinVar as Pathogenic. ClinVar VariationId is 386.Status of the report is no_assertion_criteria_provided, 0 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.854

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000308.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CTSA	NM_000308.4	MANE Select	c.1217T>A	p.Met406Lys	missense	Exon 13 of 15	NP_000299.3	P10619-1
	CTSA	NM_001127695.3		c.1217T>A	p.Met406Lys	missense	Exon 13 of 15	NP_001121167.1	P10619-1
	CTSA	NM_001167594.3		c.1166T>A	p.Met389Lys	missense	Exon 12 of 14	NP_001161066.2	P10619-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CTSA	ENST00000646241.3	MANE Select	c.1217T>A	p.Met406Lys	missense	Exon 13 of 15	ENSP00000493613.2	P10619-1
	CTSA	ENST00000372484.8	TSL:1	c.1271T>A	p.Met424Lys	missense	Exon 13 of 15	ENSP00000361562.3	X6R8A1
	CTSA	ENST00000191018.9	TSL:1	c.1217T>A	p.Met406Lys	missense	Exon 13 of 15	ENSP00000191018.5	P10619-1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 151960 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000242

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.: 29

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 151960 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74210

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.0000242 AC: 1 AN: 41366

American (AMR) AF: 0.00 AC: 0 AN: 15242

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5152

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10588

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68000

Other (OTH) AF: 0.00 AC: 0 AN: 2088

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.76
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Uncertain	0.090
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.59	D
Eigen	Pathogenic	0.70
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.96	D
M_CAP	Uncertain	0.14	D
MetaRNN	Pathogenic	0.85	D
MetaSVM	Uncertain	0.42	D
MutationAssessor	Uncertain	2.1	M
PhyloP100		7.7
PrimateAI	Uncertain	0.67	T
PROVEAN	Uncertain	-4.0	D
REVEL	Pathogenic	0.74
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		0.99	D
Vest4		0.80
MutPred		0.77		Loss of stability (P = 0.0168)
MVP		0.98
MPC		1.2
ClinPred		0.99	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.94
gMVP		0.83
Mutation Taster		=13/87	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs137854548; hg19: chr20-44526408;