20-58909186-C-G

Variant names:

• chr20-58909186-C-G
• rs8620
• NM_080425.4:c.2484C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000516.7(GNAS):​c.555C>G​(p.Ile185Met) 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 pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. I185I) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GNAS NM_000516.7 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.27
• Publications: 19 publications found

Genes affected

GNAS (HGNC:4392): (GNAS complex locus) This locus has a highly complex imprinted expression pattern. It gives rise to maternally, paternally, and biallelically expressed transcripts that are derived from four alternative promoters and 5' exons. Some transcripts contain a differentially methylated region (DMR) at their 5' exons, and this DMR is commonly found in imprinted genes and correlates with transcript expression. An antisense transcript is produced from an overlapping locus on the opposite strand. One of the transcripts produced from this locus, and the antisense transcript, are paternally expressed noncoding RNAs, and may regulate imprinting in this region. In addition, one of the transcripts contains a second overlapping ORF, which encodes a structurally unrelated protein - Alex. Alternative splicing of downstream exons is also observed, which results in different forms of the stimulatory G-protein alpha subunit, a key element of the classical signal transduction pathway linking receptor-ligand interactions with the activation of adenylyl cyclase and a variety of cellular reponses. Multiple transcript variants encoding different isoforms have been found for this gene. Mutations in this gene result in pseudohypoparathyroidism type 1a, pseudohypoparathyroidism type 1b, Albright hereditary osteodystrophy, pseudopseudohypoparathyroidism, McCune-Albright syndrome, progressive osseus heteroplasia, polyostotic fibrous dysplasia of bone, and some pituitary tumors. [provided by RefSeq, Aug 2012]

GNAS Gene-Disease associations (from GenCC):

• McCune-Albright syndrome

  Inheritance: AD, Unknown Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics, G2P
• progressive osseous heteroplasia

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE, NO_KNOWN Submitted by: Orphanet, Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
• pseudohypoparathyroidism type 1A

  Inheritance: AD, Mitochondrial Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• pseudohypoparathyroidism type 1B

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, G2P
• pseudohypoparathyroidism type 1C

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Genomics England PanelApp
• pseudopseudohypoparathyroidism

  Inheritance: AD, Mitochondrial Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, G2P, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 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, 7 uncertain in NM_000516.7
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.882

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000516.7. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GNAS	NM_080425.4	MANE Plus Clinical	c.2484C>G	p.Ile828Met	missense	Exon 7 of 13	NP_536350.2	Q5JWF2-1
	GNAS	NM_000516.7	MANE Select	c.555C>G	p.Ile185Met	missense	Exon 7 of 13	NP_000507.1	P63092-1
	GNAS	NM_016592.5	MANE Plus Clinical	c.*461C>G		3_prime_UTR	Exon 7 of 13	NP_057676.1	O95467-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GNAS	ENST00000371100.9	TSL:5 MANE Plus Clinical	c.2484C>G	p.Ile828Met	missense	Exon 7 of 13	ENSP00000360141.3	Q5JWF2-1
	GNAS	ENST00000371085.8	TSL:1 MANE Select	c.555C>G	p.Ile185Met	missense	Exon 7 of 13	ENSP00000360126.3	P63092-1
	GNAS	ENST00000676826.2		c.2487C>G	p.Ile829Met	missense	Exon 7 of 13	ENSP00000504675.2	A0A7I2V5R6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 868

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.65
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.16
CADD	Uncertain	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.81	D
Eigen	Uncertain	0.44
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.88	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.1	M
PhyloP100		1.3
PrimateAI	Uncertain	0.70	T
PROVEAN	Benign	-2.2	N
REVEL	Pathogenic	0.82
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.012	D
Polyphen		0.99	D
Vest4		0.53
MutPred		0.66		Gain of sheet (P = 0.0011)
MVP		0.98
MPC		3.1
ClinPred		0.99	D
GERP RS		4.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.88
gMVP		0.90
Mutation Taster		=90/10	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: rs8620; hg19: chr20-57484241;