4-54698430-T-C

Variant names:

• chr4-54698430-T-C
• rs201222895
• NM_000222.3:c.484T>C

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_000222.3(KIT):​c.484T>C​(p.Phe162Leu) 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. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: KIT NM_000222.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 2.62

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 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 piebaldism, gastrointestinal stromal tumor, mastocytosis, cutaneous mastocytosis.
• BP4: Computational evidence support a benign effect (MetaRNN=0.17921102).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KIT	NM_000222.3	c.484T>C	p.Phe162Leu	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.484T>C	p.Phe162Leu	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:2

Revision: criteria provided, single submitter

Submissions by phenotype

KIT-related disorder Uncertain:1

Oct 25, 2023

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

The KIT c.484T>C variant is predicted to result in the amino acid substitution p.Phe162Leu. To our knowledge, this variant has not been reported in the literature or in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. This variant is interpreted as uncertain significance in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/942277/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Gastrointestinal stromal tumor Uncertain:1

Sep 23, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The leucine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with KIT-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces phenylalanine with leucine at codon 162 of the KIT protein (p.Phe162Leu). The phenylalanine residue is highly conserved and there is a small physicochemical difference between phenylalanine and leucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.85
BayesDel_addAF	Benign	-0.045	T
BayesDel_noAF	Benign	-0.30
CADD	Benign	21
DANN	Benign	0.93
DEOGEN2	Uncertain	0.59	.;D
Eigen	Benign	-0.48
Eigen_PC	Benign	-0.39
FATHMM_MKL	Benign	0.46	N
LIST_S2	Benign	0.78	T;T
M_CAP	Benign	0.040	D
MetaRNN	Benign	0.18	T;T
MetaSVM	Benign	-0.87	T
MutationAssessor	Benign	1.7	L;L
PrimateAI	Uncertain	0.54	T
PROVEAN	Uncertain	-3.4	D;D
REVEL	Benign	0.15
Sift	Benign	0.090	T;T
Sift4G	Benign	0.24	T;T
Polyphen		0.012	B;B
Vest4		0.35
MutPred		0.45		Gain of disorder (P = 0.0604);Gain of disorder (P = 0.0604);
MVP		0.71
MPC		0.54
ClinPred		0.57	D
GERP RS		4.4
Varity_R		0.27
gMVP		0.85

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

LitVar

Other links and lift over

dbSNP: rs201222895; hg19: chr4-55564596;