NM_020451.3:c.8_9insTGCCGGGCCG

Variant names:

• chr1-25800232-T-TGGGCCGTGCC
• rs2124436380
• NM_020451.3:c.8_9insTGCCGGGCCG

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_020451.3(SELENON):​c.8_9insTGCCGGGCCG​(p.Arg5GlyfsTer81) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. R3R) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 30)
• Consequence: SELENON NM_020451.3 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 0.342
• Publications: 0 publications found

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]

SELENON Gene-Disease associations (from GenCC):

• rigid spine muscular dystrophy 1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, G2P, Ambry Genetics
• SELENON-related myopathy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• congenital myopathy 4A, autosomal dominant

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• congenital fiber-type disproportion myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• desmin-related myopathy with Mallory body-like inclusions

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• rigid spine syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 81 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-25800232-T-TGGGCCGTGCC is Pathogenic according to our data. Variant chr1-25800232-T-TGGGCCGTGCC is described in ClinVar as Pathogenic. ClinVar VariationId is 1445921.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_020451.3. 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
	SELENON	NM_020451.3	MANE Select	c.8_9insTGCCGGGCCG	p.Arg5GlyfsTer81	frameshift	Exon 1 of 13	NP_065184.2
	SELENON	NM_206926.2		c.8_9insTGCCGGGCCG	p.Arg5GlyfsTer81	frameshift	Exon 1 of 12	NP_996809.1	Q9NZV5-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SELENON	ENST00000361547.7	TSL:1 MANE Select	c.8_9insTGCCGGGCCG	p.Arg5GlyfsTer81	frameshift	Exon 1 of 13	ENSP00000355141.2	Q9NZV5-1
	SELENON	ENST00000374315.1	TSL:5	c.8_9insTGCCGGGCCG	p.Arg5GlyfsTer81	frameshift	Exon 1 of 12	ENSP00000363434.1	Q9NZV5-2
	SELENON	ENST00000354177.9	TSL:5	c.8_9insTGCCGGGCCG	p.Arg5GlyfsTer81	frameshift	Exon 1 of 12	ENSP00000346109.5	H9KV50

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 8

GnomAD4 genome Cov.: 30

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Eichsfeld type congenital muscular dystrophy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.34

Splicing

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

Other links and lift over

dbSNP: rs2124436380; hg19: chr1-26126723;