NM_020451.3:c.979C>G

Variant names:

• chr1-25809789-C-G
• NM_020451.3:c.979C>G

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_020451.3(SELENON):​c.979C>G​(p.Arg327Gly) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,686 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R327H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SELENON NM_020451.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 4.94

Genes affected

SELENON (HGNC:15999): (selenoprotein N) This gene encodes a glycoprotein that is localized in the endoplasmic reticulum. It plays an important role in cell protection against oxidative stress, and in the regulation of redox-related calcium homeostasis. Mutations in this gene are associated with early onset muscle disorders, referred to as SEPN1-related myopathy. SEPN1-related myopathy consists of 4 autosomal recessive disorders, originally thought to be separate entities: rigid spine muscular dystrophy (RSMD1), the classical form of multiminicore disease, desmin related myopathy with Mallory-body like inclusions, and congenital fiber-type disproportion (CFTD). This protein is a selenoprotein, containing the rare amino acid selenocysteine (Sec). Sec is encoded by the UGA codon, which normally signals translation termination. The 3' UTRs of selenoprotein mRNAs contain a conserved stem-loop structure, designated the Sec insertion sequence (SECIS) element, that is necessary for the recognition of UGA as a Sec codon, rather than as a stop signal. A second stop-codon redefinition element (SRE) adjacent to the UGA codon has been identified in this gene (PMID:15791204). SRE is a phylogenetically conserved stem-loop structure that stimulates readthrough at the UGA codon, and augments the Sec insertion efficiency by SECIS. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Dec 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.836

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SELENON	NM_020451.3	c.979C>G	p.Arg327Gly	missense_variant	Exon 7 of 13	ENST00000361547.7	NP_065184.2
SELENON	NM_206926.2	c.877C>G	p.Arg293Gly	missense_variant	Exon 6 of 12		NP_996809.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SELENON	ENST00000361547.7	c.979C>G	p.Arg327Gly	missense_variant	Exon 7 of 13	1	NM_020451.3	ENSP00000355141.2
SELENON	ENST00000374315.1	c.877C>G	p.Arg293Gly	missense_variant	Exon 6 of 12	5		ENSP00000363434.1
SELENON	ENST00000354177.9	c.808C>G	p.Arg270Gly	missense_variant	Exon 6 of 12	5		ENSP00000346109.5
SELENON	ENST00000494537.2	n.877C>G		non_coding_transcript_exon_variant	Exon 6 of 13	3		ENSP00000508308.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461686 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727154

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.60	.;D;.
Eigen	Uncertain	0.61
Eigen_PC	Uncertain	0.54
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.93	D;D;D
M_CAP	Uncertain	0.20	D
MetaRNN	Pathogenic	0.84	D;D;D
MetaSVM	Uncertain	0.68	D
MutationAssessor	Uncertain	2.2	.;M;.
PrimateAI	Uncertain	0.66	T
PROVEAN	Pathogenic	-4.4	D;D;D
REVEL	Pathogenic	0.74
Sift	Benign	0.040	D;D;D
Sift4G	Uncertain	0.016	D;D;D
Polyphen		1.0	.;D;D
Vest4		0.93
MutPred		0.44		.;Gain of loop (P = 0.0312);.;
MVP		0.97
MPC		0.74
ClinPred		0.97	D
GERP RS		4.8
Varity_R		0.44

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr1-26136280; COSMIC: COSV104668580; COSMIC: COSV104668580;