chr20-58853893-G-A

Position:

• chr20-58853893-G-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_080425.4(GNAS):​c.628G>A​(p.Ala210Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000414 in 1,449,042 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A210P) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: GNAS NM_080425.4 missense
• Clinical Significance: Uncertain significance no assertion criteria provided U:1
• Conservation: PhyloP100: -1.96

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 (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.05431351).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GNAS	NM_016592.5	c.*42+13007G>A		intron_variant		ENST00000371075.7	NP_057676.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GNAS	ENST00000676826.2	c.628G>A	p.Ala210Thr	missense_variant	1/13			ENSP00000504675.2
GNAS	ENST00000371102.8	c.628G>A	p.Ala210Thr	missense_variant	1/12	5		ENSP00000360143.4
GNAS	ENST00000371075.7	c.*42+13007G>A		intron_variant		1	NM_016592.5	ENSP00000360115.3
GNAS	ENST00000663479.2	c.-39+12018G>A		intron_variant				ENSP00000499353.2
GNAS	ENST00000462499.6	c.-39+12018G>A		intron_variant		2		ENSP00000499758.2
GNAS	ENST00000467227.6	c.-39+9819G>A		intron_variant		3		ENSP00000499681.2
GNAS	ENST00000453292.7	c.*42+13007G>A		intron_variant		5		ENSP00000392000.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000448 AC: 1 AN: 223074 Hom.: 0 AF XY: 0.00000822 AC XY: 1 AN XY: 121688

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: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000101

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000414 AC: 6 AN: 1449042 Hom.: 0 Cov.: 33 AF XY: 0.00000417 AC XY: 3 AN XY: 719754

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000511

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000362

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000829 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: no assertion criteria provided

Submissions by phenotype

GNAS-related disorder Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Feb 02, 2024

The GNAS c.628G>A variant is predicted to result in the amino acid substitution p.Ala210Thr. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.0010% of alleles in individuals of European (Non-Finnish) descent in gnomAD. 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	Benign	0.076
BayesDel_addAF	Benign	-0.15	T
BayesDel_noAF	Benign	-0.46
CADD	Benign	0.047
DANN	Benign	0.59
DEOGEN2	Benign	0.24	T;.;.
Eigen	Benign	-1.5
Eigen_PC	Benign	-1.6
FATHMM_MKL	Benign	0.057	N
LIST_S2	Benign	0.54	T;T;T
M_CAP	Benign	0.032	D
MetaRNN	Benign	0.054	T;T;T
MetaSVM	Benign	-0.63	T
MutationAssessor	Benign	0.90	L;.;L
PrimateAI	Benign	0.41	T
PROVEAN	Benign	-0.60	N;N;N
REVEL	Benign	0.16
Sift	Benign	0.42	T;T;T
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		0.079	B;.;.
Vest4		0.052
MutPred		0.21		Gain of phosphorylation at A210 (P = 0.0024);Gain of phosphorylation at A210 (P = 0.0024);Gain of phosphorylation at A210 (P = 0.0024);
MVP		0.46
MPC		0.39
ClinPred		0.037	T
GERP RS		-2.1
Varity_R		0.042
gMVP		0.080

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs61749696; hg19: chr20-57428948; COSMIC: COSV58339485; COSMIC: COSV58339485;