Genetic Variant NM_138283.1:c.224C>T (chr20-23443938-C-T) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_138283.1(CSTL1):c.224C>T(p.Thr75Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000174 in 1,612,678 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000017 ( 0 hom. )

Consequence

CSTL1
NM_138283.1 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.44

Variant links:

Genes affected

CSTL1 (HGNC:15958): (cystatin like 1) 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 at the telomeric end of the cystatin locus and encodes a type 2 cystatin-like protein. The specific function of this protein has not been determined. [provided by RefSeq, Jul 2008]

CSTL1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CSTL1	NM_138283.1 link	c.224C>T	p.Thr75Met	missense_variant	Exon 3 of 4	ENST00000347397.5	NP_612140.1	Q9H114

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CSTL1	ENST00000347397.5 link	c.224C>T	p.Thr75Met	missense_variant	Exon 3 of 4	1	NM_138283.1	ENSP00000344907.1		Q9H114
CSTL1	ENST00000246020.3 link	c.224C>T	p.Thr75Met	missense_variant	Exon 3 of 4	1		ENSP00000246020.2		Q9H114

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152166

Hom.:

Cov.:

show subpopulations

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

GnomAD3 exomes

AF:

0.0000279

AC:

AN:

250986

Hom.:

AF XY:

0.0000369

AC XY:

AN XY:

135622

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000579

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.000131

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000881

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000171

AC:

AN:

1460512

Hom.:

Cov.:

AF XY:

0.0000124

AC XY:

AN XY:

726632

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000671

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000580

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000135

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74322

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.0000340

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Nov 21, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.224C>T (p.T75M) alteration is located in exon 3 (coding exon 2) of the CSTL1 gene. This alteration results from a C to T substitution at nucleotide position 224, causing the threonine (T) at amino acid position 75 to be replaced by a methionine (M). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.22

BayesDel_addAF

Benign

-0.12

BayesDel_noAF

Benign

-0.18

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Benign

0.024

T;T

Eigen

Uncertain

0.47

Eigen_PC

Uncertain

0.35

FATHMM_MKL

Benign

0.59

LIST_S2

Benign

0.75

T;.

M_CAP

Benign

0.015

MetaRNN

Uncertain

0.66

D;D

MetaSVM

Benign

-0.64

PrimateAI

Uncertain

0.62

PROVEAN

Benign

-1.9

N;N

REVEL

Benign

0.24

Sift

Uncertain

0.0060

D;D

Sift4G

Uncertain

0.013

D;D

Polyphen

1.0

D;D

Vest4

0.57

MutPred

0.64

Gain of MoRF binding (P = 0.0728);Gain of MoRF binding (P = 0.0728);

MVP

0.22

MPC

0.36

ClinPred

0.74

GERP RS

4.1

Varity_R

0.17

gMVP

0.55

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over