chr20-58891728-T-C

Variant names:

• chr20-58891728-T-C
• rs1555883949
• NM_000516.7:c.2T>C

Variant summary

Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PVS1 PS1_Moderate PM2 PP5_Very_Strong

The NM_000516.7(GNAS):​c.2T>C​(p.Met1?) variant causes a start lost 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. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 28)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: GNAS NM_000516.7 start_lost
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 3.26
• Publications: 0 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: G2P, Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics
• progressive osseous heteroplasia

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

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

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

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

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

ACMG classification

Our verdict: Pathogenic. The variant received 20 ACMG points.

• PVS1: Start lost variant, next in-frame start position is after 38 pathogenic variants. Next in-frame start position is after 60 codons. Genomic position: 58895650. Lost 0.150 part of the original CDS.
• PS1: Another start lost variant in NM_000516.7 (GNAS) was described as [Likely_pathogenic] in ClinVar
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 20-58891728-T-C is Pathogenic according to our data. Variant chr20-58891728-T-C is described in ClinVar as Pathogenic. ClinVar VariationId is 499177.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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_000516.7	MANE Select	c.2T>C	p.Met1?	start_lost	Exon 1 of 13	NP_000507.1
	GNAS	NM_080425.4	MANE Plus Clinical	c.2069-3884T>C		intron	N/A	NP_536350.2
	GNAS	NM_016592.5	MANE Plus Clinical	c.*43-3884T>C		intron	N/A	NP_057676.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GNAS	ENST00000371085.8	TSL:1 MANE Select	c.2T>C	p.Met1?	start_lost	Exon 1 of 13	ENSP00000360126.3
	GNAS	ENST00000354359.12	TSL:1	c.2T>C	p.Met1?	start_lost	Exon 1 of 13	ENSP00000346328.7
	GNAS	ENST00000371095.7	TSL:1	c.2T>C	p.Met1?	start_lost	Exon 1 of 12	ENSP00000360136.3

Frequencies

GnomAD3 genomes Cov.: 28

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 1005396 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 487100

African (AFR) AF: 0.00 AC: 0 AN: 20502

American (AMR) AF: 0.00 AC: 0 AN: 24640

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 12274

East Asian (EAS) AF: 0.00 AC: 0 AN: 8282

South Asian (SAS) AF: 0.00 AC: 0 AN: 42982

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 20374

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 2464

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 840174

Other (OTH) AF: 0.00 AC: 0 AN: 33704

GnomAD4 genome Cov.: 28

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
2	-	-	not provided (2)
1	-	-	See cases (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.27
CADD	Uncertain	24
DANN	Benign	0.95
DEOGEN2	Uncertain	0.54	D
Eigen	Benign	0.18
Eigen_PC	Benign	0.047
FATHMM_MKL	Benign	0.28	N
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.87	D
PhyloP100		3.3
PROVEAN	Uncertain	-2.8	D
REVEL	Pathogenic	0.79
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.57
MutPred		0.98		Gain of phosphorylation at M1 (P = 0.0771)
MVP		0.91
ClinPred		0.90	D
GERP RS		1.9
PromoterAI		-0.46	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.3
Mutation Taster		=4/196	disease causing (ClinVar)

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: rs1555883949; hg19: chr20-57466783;