Genetic Variant MC4R:p.Tyr302* (chr18-60371444-A-C) – ACMG Classification: Likely_pathogenic (8 pts)

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_StrongPM2PP5_Moderate

The NM_005912.3(MC4R):c.906T>G(p.Tyr302*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,866 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 Likely pathogenic (★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MC4R
NM_005912.3 stop_gained

Scores

Clinical Significance

Likely pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 0.640

Variant links:

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]

MC4R links:

ENSG00000285681 (HGNC:):

ENSG00000285681 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 6 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 18-60371444-A-C is Pathogenic according to our data. Variant chr18-60371444-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3076076.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MC4R	NM_005912.3 link	c.906T>G	p.Tyr302*	stop_gained	Exon 1 of 1	ENST00000299766.5	NP_005903.2	P32245

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
MC4R	ENST00000299766.5 link	c.906T>G	p.Tyr302*	stop_gained	Exon 1 of 1	6	NM_005912.3	ENSP00000299766.3	P32245
ENSG00000285681	ENST00000650201.1 link	n.113+42099A>C		intron_variant	Intron 1 of 3
ENSG00000285681	ENST00000658928.1 link	n.156+42099A>C		intron_variant	Intron 1 of 3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251404

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135870

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461866

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727234

show subpopulations

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:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Obesity due to melanocortin 4 receptor deficiency

Pathogenic:1

Sep 19, 2018

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Tyr302X variant in MC4R has not been previously reported in individuals with obesity, but has been identified in 1/30782 South Asian chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org/). This nonsense variant leads to a premature termination codon at position 302. The MC4R protein is encoded by a single exon; therefore, this alteration is more likely to escape nonsense mediated decay (NMD), resulting in a truncated protein that is missing the c-terminal tail. The c-terminal tail contains a peptide signal which is required for targeting the MC4R protein to the plasma membrane, and removal of that peptide results in cytoplasmic retention of the MC4R protein (Ho 1999). Haploinsufficiency of the MC4R gene is an established disease mechanism in MC4R-related obesity. In summary, although additional studies are required to fully establish its clinical significance, the p.Tyr302X variant is likely pathogenic. ACMG/AMP Criteria applied: PVS1_Moderate, PM2, PM1. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.56

BayesDel_noAF

Pathogenic

0.60

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Uncertain

0.51

Eigen_PC

Uncertain

0.35

FATHMM_MKL

Uncertain

0.88

Vest4

0.85

GERP RS

2.4

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.32

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.32

Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

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