chr20-23879541-A-C

Variant names:

• chr20-23879541-A-C
• rs1799841
• NM_001900.5:c.136T>G

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_001900.5(CST5):​c.136T>G​(p.Cys46Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. C46Y) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CST5 NM_001900.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -1.92
• Publications: 0 publications found

Genes affected

CST5 (HGNC:2477): (cystatin D) 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 protein found in saliva and tears. The encoded protein may play a protective role against proteinases present in the oral cavity. [provided by RefSeq, Jul 2008]

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.037451923).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001900.5. 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
	CST5	NM_001900.5	MANE Select	c.136T>G	p.Cys46Gly	missense	Exon 1 of 3	NP_001891.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CST5	ENST00000304710.5	TSL:1 MANE Select	c.136T>G	p.Cys46Gly	missense	Exon 1 of 3	ENSP00000307132.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 51

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.051
BayesDel_addAF	Benign	-0.33	T
BayesDel_noAF	Benign	-0.71
CADD	Benign	3.2
DANN	Benign	0.57
DEOGEN2	Benign	0.033	T
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.5
FATHMM_MKL	Benign	0.0020	N
LIST_S2	Benign	0.25	T
M_CAP	Benign	0.0013	T
MetaRNN	Benign	0.037	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.14	N
PhyloP100		-1.9
PrimateAI	Benign	0.28	T
PROVEAN	Benign	0.87	N
REVEL	Benign	0.0070
Sift	Uncertain	0.0050	D
Sift4G	Uncertain	0.016	D
Polyphen		0.0020	B
Vest4		0.064
MutPred		0.43		Gain of disorder (P = 0.0149)
MVP		0.048
MPC		0.0050
ClinPred		0.11	T
GERP RS		-0.40
PromoterAI		-0.0034	Neutral
Varity_R		0.15
gMVP		0.17
Mutation Taster		=96/4	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: rs1799841; hg19: chr20-23860178;