dbSNP rs572852980: KIT:p.Ile748Thr (chr4-54731880-T-C) – ACMG Classification: Benign (-8 pts)

Variant summary

Our verdict is Benign. The variant received -8 ACMG points: 1P and 9B. PP2BP4_StrongBP6BS2

The NM_000222.3(KIT):c.2243T>C(p.Ile748Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000806 in 1,613,434 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 variant affecting the same amino acid position, but resulting in a different missense (i.e. I748V) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000062 ( 0 hom. )

Consequence

KIT
NM_000222.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:1

Conservation

PhyloP100: 1.43

Publications

7 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: Benign. The variant received -8 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=0.055396527).

BP6

Variant 4-54731880-T-C is Benign according to our data. Variant chr4-54731880-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 237258.

BS2

High AC in GnomAdExome4 at 9 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.2243T>C	p.Ile748Thr	missense	Exon 16 of 21	NP_000213.1	P10721-1
KIT	NM_001385284.1		c.2246T>C	p.Ile749Thr	missense	Exon 16 of 21	NP_001372213.1	A0A8I5KS03
KIT	NM_001385290.1		c.2243T>C	p.Ile748Thr	missense	Exon 16 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.2243T>C	p.Ile748Thr	missense	Exon 16 of 21	ENSP00000288135.6	P10721-1
KIT	ENST00000412167.7	TSL:1	c.2231T>C	p.Ile744Thr	missense	Exon 16 of 21	ENSP00000390987.3	A0A8J8Z860
KIT	ENST00000687109.1		c.2246T>C	p.Ile749Thr	missense	Exon 16 of 21	ENSP00000509371.1	A0A8I5KS03

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

151958

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000386

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

GnomAD2 exomes

AF:

0.00000796

AC:

AN:

251236

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000109

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000616

AC:

AN:

1461358

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726998

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33452

American (AMR)

AF:

0.00

AC:

AN:

44714

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26108

East Asian (EAS)

AF:

0.0000756

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86242

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111594

Other (OTH)

AF:

0.0000994

AC:

AN:

60374

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.514

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:

0.0000263

AC:

AN:

152076

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74350

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

41508

American (AMR)

AF:

0.000131

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000387

AC:

AN:

5168

South Asian (SAS)

AF:

0.00

AC:

AN:

4800

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10604

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67954

Other (OTH)

AF:

0.00

AC:

AN:

2108

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.00955443), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.388

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:

0.0000712

Hom.:

Bravo

AF:

0.0000151

ExAC

AF:

0.00000824

AC:

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 (1)

not provided (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.067

BayesDel_addAF

Benign

-0.26

BayesDel_noAF

Benign

-0.38

CADD

Benign

(source)

DANN

Benign

0.59

DEOGEN2

Benign

0.41

Eigen

Benign

-0.34

Eigen_PC

Benign

-0.18

FATHMM_MKL

Uncertain

0.87

LIST_S2

Benign

0.81

M_CAP

Benign

0.016

MetaRNN

Benign

0.055

MetaSVM

Benign

-0.92

MutationAssessor

Benign

1.2

PhyloP100

1.4

PrimateAI

Uncertain

0.50

PROVEAN

Benign

-0.97

REVEL

Benign

0.27

Sift

Benign

0.95

Sift4G

Benign

0.41

Polyphen

0.013

Vest4

0.083

MutPred

0.52

Gain of glycosylation at Y747 (P = 0.0075)

MVP

0.59

MPC

0.58

ClinPred

0.032

GERP RS

4.8

Varity_R

0.057

gMVP

0.74

Mutation Taster

=94/6

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