Genetic Variant KIT:p.Val50Leu (chr4-54695592-G-T) – ACMG Classification: Likely_benign (-6 pts)

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 1P and 7B. PP2BP4_ModerateBS1_SupportingBS2

The NM_000222.3(KIT):c.148G>T(p.Val50Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000539 in 1,614,054 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V50M) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000048 ( 0 hom. )

Consequence

KIT
NM_000222.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8B:2

Conservation

PhyloP100: 2.69

Publications

27 publications found

Variant links:

Genes affected

KIT (HGNC:6342): (KIT proto-oncogene, receptor tyrosine kinase) This gene encodes a receptor tyrosine kinase. This gene was initially identified as a homolog of the feline sarcoma viral oncogene v-kit and is often referred to as proto-oncogene c-Kit. The canonical form of this glycosylated transmembrane protein has an N-terminal extracellular region with five immunoglobulin-like domains, a transmembrane region, and an intracellular tyrosine kinase domain at the C-terminus. Upon activation by its cytokine ligand, stem cell factor (SCF), this protein phosphorylates multiple intracellular proteins that play a role in in the proliferation, differentiation, migration and apoptosis of many cell types and thereby plays an important role in hematopoiesis, stem cell maintenance, gametogenesis, melanogenesis, and in mast cell development, migration and function. This protein can be a membrane-bound or soluble protein. Mutations in this gene are associated with gastrointestinal stromal tumors, mast cell disease, acute myelogenous leukemia, and piebaldism. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2020]

KIT Gene-Disease associations (from GenCC):

gastrointestinal stromal tumor
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, ClinGen, Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae)
piebaldism
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Ambry Genetics, G2P, Orphanet, Labcorp Genetics (formerly Invitae)
cutaneous mastocytosis
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
mastocytosis
Inheritance: AD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics

KIT links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -6 ACMG points.

PP2

Missense variant in the KIT gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 54 curated pathogenic missense variants (we use a threshold of 10). The gene has 7 curated benign missense variants. Gene score misZ: 2.5806 (below the threshold of 3.09). Trascript score misZ: 4.1549 (above the threshold of 3.09). GenCC associations: The gene is linked to cutaneous mastocytosis, gastrointestinal stromal tumor, mastocytosis, piebaldism.

BP4

Computational evidence support a benign effect (MetaRNN=0.09165344).

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000112 (17/152174) while in subpopulation NFE AF = 0.00025 (17/68032). AF 95% confidence interval is 0.000159. There are 0 homozygotes in GnomAd4. There are 6 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

BS2

High AC in GnomAd4 at 17 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000222.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
KIT	NM_000222.3	MANE Select	c.148G>T	p.Val50Leu	missense	Exon 2 of 21	NP_000213.1	P10721-1
KIT	NM_001385284.1		c.148G>T	p.Val50Leu	missense	Exon 2 of 21	NP_001372213.1	A0A8I5KS03
KIT	NM_001385290.1		c.148G>T	p.Val50Leu	missense	Exon 2 of 21	NP_001372219.1	A0A8I5QKP7

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
KIT	ENST00000288135.6	TSL:1 MANE Select	c.148G>T	p.Val50Leu	missense	Exon 2 of 21	ENSP00000288135.6	P10721-1
KIT	ENST00000412167.7	TSL:1	c.148G>T	p.Val50Leu	missense	Exon 2 of 21	ENSP00000390987.3	A0A8J8Z860
KIT	ENST00000689994.1		c.-363G>T		5_prime_UTR_premature_start_codon_gain	Exon 2 of 21	ENSP00000509156.1	A0A8I5KRE7

Frequencies

GnomAD3 genomes

AF:

0.000112

AC:

AN:

152174

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:

0.00

Gnomad NFE

AF:

0.000250

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000319

AC:

AN:

251094

AF XY:

0.0000295

show subpopulations

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:

0.0000924

Gnomad NFE exome

AF:

0.0000529

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000479

AC:

AN:

1461880

Hom.:

Cov.:

AF XY:

0.0000509

AC XY:

AN XY:

727238

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.000112

AC:

AN:

53410

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000558

AC:

AN:

1112010

Other (OTH)

AF:

0.0000166

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.486

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000112

AC:

AN:

152174

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74334

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41456

American (AMR)

AF:

0.00

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10604

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000250

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.507

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000146

Hom.:

Bravo

AF:

0.0000340

ExAC

AF:

0.0000494

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

Gastrointestinal stromal tumor (2)

Hereditary cancer-predisposing syndrome (2)

not provided (2)

Acute myeloid leukemia;C0080024:Piebaldism;C0238198:Gastrointestinal stromal tumor;C1136033:Cutaneous mastocytosis;C1336708:Germ cell tumor of testis (1)

Mastocytosis (1)

not specified (1)

Piebaldism (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Benign

-0.54

BayesDel_noAF

Benign

-0.63

CADD

Benign

7.7

(source)

DANN

Benign

0.53

DEOGEN2

Benign

0.21

Eigen

Benign

-0.77

Eigen_PC

Benign

-0.69

FATHMM_MKL

Benign

0.12

LIST_S2

Uncertain

0.88

M_CAP

Benign

0.0081

MetaRNN

Benign

0.092

MetaSVM

Benign

-0.98

MutationAssessor

Benign

0.88

PhyloP100

2.7

PrimateAI

Benign

0.32

PROVEAN

Benign

-0.090

REVEL

Benign

0.13

Sift

Benign

0.68

Sift4G

Benign

0.80

Polyphen

0.0010

Vest4

0.18

MutPred

0.38

Gain of disorder (P = 0.2037)

MVP

0.42

MPC

0.47

ClinPred

0.42

GERP RS

4.3

Varity_R

0.095

gMVP

0.61

Mutation Taster

=97/3

polymorphism

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over