rs1555623738

Positions:

• chr16-89919376-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_002386.4(MC1R):​c.118A>C​(p.Ile40Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,980 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict 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. I40T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MC1R NM_002386.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.882

Genes affected

MC1R (HGNC:6929): (melanocortin 1 receptor) This intronless gene encodes the receptor protein for melanocyte-stimulating hormone (MSH). The encoded protein, a seven pass transmembrane G protein coupled receptor, controls melanogenesis. Two types of melanin exist: red pheomelanin and black eumelanin. Gene mutations that lead to a loss in function are associated with increased pheomelanin production, which leads to lighter skin and hair color. Eumelanin is photoprotective but pheomelanin may contribute to UV-induced skin damage by generating free radicals upon UV radiation. Binding of MSH to its receptor activates the receptor and stimulates eumelanin synthesis. This receptor is a major determining factor in sun sensitivity and is a genetic risk factor for melanoma and non-melanoma skin cancer. Over 30 variant alleles have been identified which correlate with skin and hair color, providing evidence that this gene is an important component in determining normal human pigment variation. [provided by RefSeq, Jul 2008]

ENSG00000198211 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.240118).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MC1R	NM_002386.4	c.118A>C	p.Ile40Leu	missense_variant	1/1	ENST00000555147.2	NP_002377.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MC1R	ENST00000555147.2	c.118A>C	p.Ile40Leu	missense_variant	1/1	6	NM_002386.4	ENSP00000451605.1
ENSG00000198211	ENST00000556922.1	c.118A>C	p.Ile40Leu	missense_variant	1/5	2		ENSP00000451560.1
MC1R	ENST00000555427.1	c.118A>C	p.Ile40Leu	missense_variant	3/4	5		ENSP00000451760.1
MC1R	ENST00000639847.1	c.118A>C	p.Ile40Leu	missense_variant	3/3	5		ENSP00000492011.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460980 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726750

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Melanoma, cutaneous malignant, susceptibility to, 5 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 01, 2021

This sequence change replaces isoleucine with leucine at codon 40 of the MC1R protein (p.Ile40Leu). The isoleucine residue is highly conserved and there is a small physicochemical difference between isoleucine and leucine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with MC1R-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.090	T
BayesDel_noAF	Benign	-0.37
CADD	Benign	0.048
DANN	Benign	0.93
DEOGEN2	Benign	0.19	.;T;T;.
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.6
FATHMM_MKL	Benign	0.27	N
LIST_S2	Uncertain	0.97	D;.;D;D
M_CAP	Uncertain	0.091	D
MetaRNN	Benign	0.24	T;T;T;T
MetaSVM	Benign	-0.83	T
MutationAssessor	Pathogenic	3.5	.;H;H;.
PROVEAN	Benign	-1.7	N;.;N;N
REVEL	Benign	0.22
Sift	Uncertain	0.0010	D;.;D;D
Sift4G	Benign	0.069	T;.;T;D
Polyphen		0.070	.;B;B;.
Vest4		0.33
MutPred		0.68		Loss of helix (P = 0.2271);Loss of helix (P = 0.2271);Loss of helix (P = 0.2271);Loss of helix (P = 0.2271);
MVP		0.29
MPC		0.019
ClinPred		0.22	T
GERP RS		-5.4
Varity_R		0.16
gMVP		0.35

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: rs1555623738; hg19: chr16-89985784;