18-11881007-G-T

Variant names:

• chr18-11881007-G-T
• rs142792291
• NM_182978.4:c.1249G>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_182978.4(GNAL):​c.1249G>T​(p.Gly417Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,764 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G417S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: GNAL NM_182978.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.68
• Publications: 1 publications found

Genes affected

GNAL (HGNC:4388): (G protein subunit alpha L) This gene encodes a stimulatory G protein alpha subunit which mediates odorant signaling in the olfactory epithelium. This protein couples dopamine type 1 receptors and adenosine A2A receptors and is widely expressed in the central nervous system. Mutations in this gene have been associated with dystonia 25 and this gene is located in a susceptibility region for bipolar disorder and schizophrenia. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2013]

GNAL Gene-Disease associations (from GenCC):

• dystonia 25

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.88

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_182978.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GNAL	NM_182978.4	MANE Select	c.1249G>T	p.Gly417Cys	missense	Exon 12 of 12	NP_892023.1
	GNAL	NM_001369387.1	MANE Plus Clinical	c.1018G>T	p.Gly340Cys	missense	Exon 12 of 12	NP_001356316.1
	GNAL	NM_001142339.3		c.1018G>T	p.Gly340Cys	missense	Exon 13 of 13	NP_001135811.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GNAL	ENST00000334049.11	TSL:1 MANE Select	c.1249G>T	p.Gly417Cys	missense	Exon 12 of 12	ENSP00000334051.5
	GNAL	ENST00000423027.8	TSL:1 MANE Plus Clinical	c.1018G>T	p.Gly340Cys	missense	Exon 12 of 12	ENSP00000408489.2
	GNAL	ENST00000535121.5	TSL:1	c.1018G>T	p.Gly340Cys	missense	Exon 13 of 13	ENSP00000439023.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251036 AF XY: 0.00

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461764 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727180

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111930

Other (OTH) AF: 0.00 AC: 0 AN: 60386

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Dystonic disorder Uncertain:1

Sep 06, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt GNAL protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This variant has not been reported in the literature in individuals affected with GNAL-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with cysteine, which is neutral and slightly polar, at codon 340 of the GNAL protein (p.Gly340Cys).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.31
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.19
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.71	D
Eigen	Pathogenic	0.73
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.80	D
MetaRNN	Pathogenic	0.88	D
MetaSVM	Pathogenic	0.83	D
MutationAssessor	Pathogenic	2.9	M
PhyloP100		7.7
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-7.5	D
REVEL	Pathogenic	0.76
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.64
MutPred		0.53		Loss of catalytic residue at G340 (P = 0.0084)
MVP		0.88
MPC		2.5
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.85
gMVP		0.90

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: rs142792291; hg19: chr18-11881006;