18-60371451-A-G

Position:

• chr18-60371451-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 6P and 1B. PM1 PP3_Strong BS2_Supporting

The NM_005912.3(MC4R):​c.899T>C​(p.Leu300Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000041 in 1,461,834 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: MC4R NM_005912.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.32

Genes affected

MC4R (HGNC:6932): (melanocortin 4 receptor) The protein encoded by this gene is a membrane-bound receptor and member of the melanocortin receptor family. The encoded protein interacts with adrenocorticotropic and MSH hormones and is mediated by G proteins. This is an intronless gene. Defects in this gene are a cause of autosomal dominant obesity. [provided by RefSeq, Jan 2010]

(HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_005912.3
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.945
• BS2: High AC in GnomAdExome4 at 6 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MC4R	NM_005912.3	c.899T>C	p.Leu300Pro	missense_variant	1/1	ENST00000299766.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MC4R	ENST00000299766.5	c.899T>C	p.Leu300Pro	missense_variant	1/1		NM_005912.3	P1
	ENST00000658928.1	n.156+42106A>G		intron_variant, non_coding_transcript_variant
	ENST00000650201.1	n.113+42106A>G		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251408 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135870

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 SAS exome AF: 0.0000653

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000410 AC: 6 AN: 1461834 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727224

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: 0.0000696

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

BODY MASS INDEX QUANTITATIVE TRAIT LOCUS 20 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Neuberg Centre For Genomic Medicine, NCGM

-

The missense variant c.899T>C (p.Leu300Pro) in MC4R gene has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. The p.Leu300Pro variant is novel (not in any individuals) in 1000 Genomes and allele frequency of 0.0007955% is reported in gnomAD. The amino acid Leu at position 300 is changed to a Pro changing protein sequence and it might alter its composition and physico-chemical properties. The amino acid change p.Leu300Pro in MC4R is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Uncertain Significance. -

MC4R-related disorder Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Mar 03, 2023

The MC4R c.899T>C variant is predicted to result in the amino acid substitution p.Leu300Pro. This variant has been reported in an individual of normal weight (Table 2, Namjou et al. 2021. PubMed ID: 32952152). This variant has been reported as a null Mc4r allele in a laboratory mouse strain referred to as "Southbeach" that exhibits severe obesity due to hyperphagia and decreased energy expenditure (Meehan et al. 2006. PubMed ID: 17143585). In vitro functional studies suggest this variant results in reduced protein surface expression and ligand binding (Table 1-3, Wang and Tao. 2011. PubMed ID: 21729752; Table 1, He and Tao. 2014. PubMed ID: 25332687; Table 3, Wang et al. 2017. PubMed ID: 28284973). This variant is reported in 2 of ~251,000 alleles in gnomAD (http://gnomad.broadinstitute.org/variant/18-58038684-A-G). Although we suspect that this variant may be pathogenic, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Uncertain	0.087	D
BayesDel_noAF	Uncertain	0.070
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.79	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.35	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Uncertain	-0.086	T
MutationAssessor	Pathogenic	3.7	H
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.66	T
PROVEAN	Pathogenic	-5.7	D
REVEL	Uncertain	0.62
Sift	Uncertain	0.0050	D
Sift4G	Uncertain	0.011	D
Polyphen		1.0	D
Vest4		0.91
MutPred		0.74		Loss of stability (P = 0.0586);
MVP		0.86
MPC		0.11
ClinPred		0.99	D
GERP RS		6.1
Varity_R		0.96
gMVP		0.99

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: rs1326028718; hg19: chr18-58038684;