4-54698301-C-T

Variant names:

• chr4-54698301-C-T
• rs1553887690
• NM_000222.3:c.355C>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_000222.3(KIT):​c.355C>T​(p.Leu119Phe) 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. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L119V) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KIT NM_000222.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.55
• Publications: 0 publications found

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: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet, ClinGen, Ambry Genetics
• piebaldism

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), Orphanet, Genomics England PanelApp
• 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

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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=0.32992488).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KIT	NM_000222.3	c.355C>T	p.Leu119Phe	missense_variant	Exon 3 of 21	ENST00000288135.6	NP_000213.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KIT	ENST00000288135.6	c.355C>T	p.Leu119Phe	missense_variant	Exon 3 of 21	1	NM_000222.3	ENSP00000288135.6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Aug 25, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.L119F variant (also known as c.355C>T), located in coding exon 3 of the KIT gene, results from a C to T substitution at nucleotide position 355. The leucine at codon 119 is replaced by phenylalanine, an amino acid with highly similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Benign	-0.081	T
BayesDel_noAF	Benign	-0.35
CADD	Benign	21
DANN	Uncertain	1.0
DEOGEN2	Benign	0.31	.;T
Eigen	Uncertain	0.22
Eigen_PC	Uncertain	0.25
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Uncertain	0.91	D;D
M_CAP	Benign	0.081	D
MetaRNN	Benign	0.33	T;T
MetaSVM	Uncertain	-0.28	T
MutationAssessor	Uncertain	2.0	M;M
PhyloP100		2.5
PrimateAI	Benign	0.40	T
PROVEAN	Benign	-1.1	N;N
REVEL	Uncertain	0.30
Sift	Benign	0.11	T;T
Sift4G	Benign	0.41	T;T
Polyphen		0.57	P;P
Vest4		0.38
MutPred		0.39		Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);
MVP		0.77
MPC		0.69
ClinPred		0.67	D
GERP RS		4.9
Varity_R		0.14
gMVP		0.86
Mutation Taster		=86/14	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: rs1553887690; hg19: chr4-55564467;