20-58840220-C-T

Variant names:

• chr20-58840220-C-T
• rs2085663948
• NM_016592.5:c.114C>T

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6 BP7

The NM_016592.5(GNAS):​c.114C>T​(p.Ser38Ser) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,458,826 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: GNAS NM_016592.5 synonymous
• Clinical Significance: Likely benign no assertion criteria provided B:1
• Conservation: PhyloP100: 0.642
• 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-AS1 (HGNC:24872): (GNAS antisense RNA 1) This gene produces a paternally-imprinted antisense RNA transcript that helps regulate the GNAS complex locus, which encodes the alpha subunit of the stimulatory G protein. Defects in this gene are a cause of pseudohypoparathyroidism type Ib.[provided by RefSeq, Jun 2010]

GNAS-AS1 Gene-Disease associations (from GenCC):

• pseudohypoparathyroidism type 1B

  Inheritance: Unknown Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

ENSG00000293655 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.49).
• BP6: Variant 20-58840220-C-T is Benign according to our data. Variant chr20-58840220-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 3349511.Status of the report is no_assertion_criteria_provided, 0 stars.
• BP7: Synonymous conserved (PhyloP=0.642 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_016592.5. 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_016592.5	MANE Plus Clinical	c.114C>T	p.Ser38Ser	synonymous	Exon 1 of 13	NP_057676.1	O95467-1
	GNAS-AS1	NR_185847.1	MANE Select	n.672+1717G>A		intron	N/A
	GNAS	NM_001410912.1		c.-624C>T		5_prime_UTR	Exon 1 of 13	NP_001397841.1	A0A0A0MR13

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GNAS	ENST00000371075.7	TSL:1 MANE Plus Clinical	c.114C>T	p.Ser38Ser	synonymous	Exon 1 of 13	ENSP00000360115.3	O95467-1
	GNAS	ENST00000313949.11	TSL:1	c.114C>T	p.Ser38Ser	synonymous	Exon 1 of 13	ENSP00000323571.7	O95467-1
	GNAS	ENST00000453292.7	TSL:5	c.114C>T	p.Ser38Ser	synonymous	Exon 1 of 12	ENSP00000392000.2	O95467-1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1458826 Hom.: 0 Cov.: 35 AF XY: 0.00000138 AC XY: 1 AN XY: 725916

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44696

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26102

East Asian (EAS) AF: 0.00 AC: 0 AN: 39692

South Asian (SAS) AF: 0.00 AC: 0 AN: 86232

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 50662

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111842

Other (OTH) AF: 0.00 AC: 0 AN: 60356

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000469 Hom.: 0

ClinVar

ClinVar submissions as Germline

Significance: Likely benign

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
-	-	1	GNAS-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.49
CADD	Benign	14
DANN	Benign	0.95
PhyloP100		0.64
PromoterAI		0.034	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
Mutation Taster		=100/0	polymorphism

Splicing

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

Other links and lift over

dbSNP: rs2085663948; hg19: chr20-57415275;