1-25800230-C-A

Variant names:

• chr1-25800230-C-A
• rs1023302860
• NM_020451.3:c.-1C>A

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_020451.3(SELENON):​c.-1C>A variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000274 in 619,450 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 0.000027 (0 hom.)
• Consequence: SELENON NM_020451.3 5_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.302
• 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 Submitted by: Ambry Genetics, G2P
• 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: Likely_benign. The variant received -2 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.44).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SELENON	NM_020451.3	c.-1C>A		5_prime_UTR_variant	Exon 1 of 13	ENST00000361547.7	NP_065184.2
SELENON	NM_206926.2	c.-1C>A		5_prime_UTR_variant	Exon 1 of 12		NP_996809.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SELENON	ENST00000361547.7	c.-1C>A		5_prime_UTR_variant	Exon 1 of 13	1	NM_020451.3	ENSP00000355141.2
SELENON	ENST00000374315.1	c.-1C>A		5_prime_UTR_variant	Exon 1 of 12	5		ENSP00000363434.1
SELENON	ENST00000354177.9	c.-1C>A		upstream_gene_variant		5		ENSP00000346109.5
SELENON	ENST00000494537.2	n.-1C>A		upstream_gene_variant		3		ENSP00000508308.1

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome AF: 0.0000274 AC: 17 AN: 619450 Hom.: 0 Cov.: 8 AF XY: 0.0000346 AC XY: 10 AN XY: 288668

African (AFR) AF: 0.00 AC: 0 AN: 11596

American (AMR) AF: 0.00 AC: 0 AN: 730

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3870

East Asian (EAS) AF: 0.00 AC: 0 AN: 2642

South Asian (SAS) AF: 0.00 AC: 0 AN: 12876

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 208

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 1222

European-Non Finnish (NFE) AF: 0.0000300 AC: 17 AN: 566052

Other (OTH) AF: 0.00 AC: 0 AN: 20254

GnomAD4 genome Cov.: 30

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

SEPN1-related disorder Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.44
CADD	Benign	11
DANN	Benign	0.94
PhyloP100		-0.30
PromoterAI		-0.31	Neutral

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: rs1023302860; hg19: chr1-26126721;