20-23688920-C-A

Variant names:

• chr20-23688920-C-A
• rs143937172
• NM_001899.3:c.50G>T

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong

The NM_001899.3(CST4):​c.50G>T​(p.Gly17Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign 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. G17E) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: CST4 NM_001899.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.297
• Publications: 2 publications found

Genes affected

CST4 (HGNC:2476): (cystatin S) The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences. Some of the members are active cysteine protease inhibitors, while others have lost or perhaps never acquired this inhibitory activity. There are three inhibitory families in the superfamily, including the type 1 cystatins (stefins), type 2 cystatins and the kininogens. The type 2 cystatin proteins are a class of cysteine proteinase inhibitors found in a variety of human fluids and secretions. The cystatin locus on chromosome 20 contains the majority of the type 2 cystatin genes and pseudogenes. This gene is located in the cystatin locus and encodes a type 2 salivary cysteine peptidase inhibitor. The protein is an S-type cystatin, based on its high level of expression in saliva, tears and seminal plasma. The specific role in these fluids is unclear but antibacterial and antiviral activity is present, consistent with a protective function. [provided by RefSeq, Jul 2008]

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.040914595).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001899.3. 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
	CST4	NM_001899.3	MANE Select	c.50G>T	p.Gly17Val	missense	Exon 1 of 3	NP_001890.1	P01036

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CST4	ENST00000217423.4	TSL:1 MANE Select	c.50G>T	p.Gly17Val	missense	Exon 1 of 3	ENSP00000217423.3	P01036

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152102 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.00316

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00 AC: 0 AN: 251386 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: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 1461688 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727136

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44714

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26122

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86240

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5756

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111876

Other (OTH) AF: 0.00 AC: 0 AN: 60386

GnomAD4 genome Data not reliable, filtered out with message: AS_VQSR AF: 0.0000197 AC: 3 AN: 152216 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74420

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

African (AFR) AF: 0.00 AC: 0 AN: 41568

American (AMR) AF: 0.00 AC: 0 AN: 15298

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3466

East Asian (EAS) AF: 0.00 AC: 0 AN: 5160

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10628

Middle Eastern (MID) AF: 0.00345 AC: 1 AN: 290

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 67958

Other (OTH) AF: 0.00 AC: 0 AN: 2112

⚠️ 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: 0.00000650 Hom.: 0

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.070
BayesDel_addAF	Benign	-0.35	T
BayesDel_noAF	Benign	-0.74
CADD	Benign	0.095
DANN	Benign	0.035
DEOGEN2	Benign	0.0071	T
Eigen	Benign	-2.2
Eigen_PC	Benign	-2.2
FATHMM_MKL	Benign	0.00010	N
LIST_S2	Benign	0.32	T
M_CAP	Benign	0.00093	T
MetaRNN	Benign	0.041	T
MetaSVM	Benign	-0.93	T
MutationAssessor	Benign	0.0	N
PhyloP100		0.30
PrimateAI	Benign	0.32	T
PROVEAN	Benign	2.8	N
REVEL	Benign	0.019
Sift	Benign	0.22	T
Sift4G	Benign	0.54	T
Polyphen		0.0	B
Vest4		0.063
MutPred		0.39		Loss of disorder (P = 0.0348)
MVP		0.088
MPC		0.0046
ClinPred		0.12	T
GERP RS		-1.7
PromoterAI		0.059	Neutral
Varity_R		0.029
gMVP		0.30
Mutation Taster		=99/1	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: rs143937172; hg19: chr20-23669557;