21-31659715-C-T

Variant names:

• chr21-31659715-C-T
• rs16988395
• NM_000454.5:c.-55C>T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4_Strong BS1_Supporting

The NM_000454.5(SOD1):​c.-55C>T variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000402 in 1,571,582 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.00021 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00042 (1 hom.)
• Consequence: SOD1 NM_000454.5 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.59

Genes affected

SOD1 (HGNC:11179): (superoxide dismutase 1) The protein encoded by this gene binds copper and zinc ions and is one of two isozymes responsible for destroying free superoxide radicals in the body. The encoded isozyme is a soluble cytoplasmic protein, acting as a homodimer to convert naturally-occuring but harmful superoxide radicals to molecular oxygen and hydrogen peroxide. The other isozyme is a mitochondrial protein. In addition, this protein contains an antimicrobial peptide that displays antibacterial, antifungal, and anti-MRSA activity against E. coli, E. faecalis, S. aureus, S. aureus MRSA LPV+, S. agalactiae, and yeast C. krusei. Mutations in this gene have been implicated as causes of familial amyotrophic lateral sclerosis. Rare transcript variants have been reported for this gene. [provided by RefSeq, Jul 2020]

SOD1-DT (HGNC:55683): (SOD1 divergent transcript)

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.75).
• BS1: Variant frequency is greater than expected in population eas. gnomad4_exome allele frequency = 0.000422 (599/1419330) while in subpopulation EAS AF= 0.00162 (64/39478). AF 95% confidence interval is 0.0013. There are 1 homozygotes in gnomad4_exome. There are 283 alleles in male gnomad4_exome subpopulation. Median coverage is 25. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SOD1	NM_000454.5	c.-55C>T		5_prime_UTR_premature_start_codon_gain_variant	Exon 1 of 5	ENST00000270142.11	NP_000445.1
SOD1	NM_000454.5	c.-55C>T		5_prime_UTR_variant	Exon 1 of 5	ENST00000270142.11	NP_000445.1
SOD1-DT	NR_187558.1	n.310G>A		non_coding_transcript_exon_variant	Exon 1 of 3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SOD1	ENST00000270142	c.-55C>T		5_prime_UTR_premature_start_codon_gain_variant	Exon 1 of 5	1	NM_000454.5	ENSP00000270142.7
SOD1	ENST00000270142	c.-55C>T		5_prime_UTR_variant	Exon 1 of 5	1	NM_000454.5	ENSP00000270142.7

Frequencies

GnomAD3 genomes AF: 0.000210 AC: 32 AN: 152252 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000145

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000578

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000323

Gnomad OTH AF: 0.000478

GnomAD4 exome AF: 0.000422 AC: 599 AN: 1419330 Hom.: 1 Cov.: 25 AF XY: 0.000399 AC XY: 283 AN XY: 708694

Gnomad4 AFR exome AF: 0.0000307

Gnomad4 AMR exome AF: 0.0000896

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00162

Gnomad4 SAS exome AF: 0.0000234

Gnomad4 FIN exome AF: 0.0000189

Gnomad4 NFE exome AF: 0.000479

Gnomad4 OTH exome AF: 0.000203

GnomAD4 genome AF: 0.000210 AC: 32 AN: 152252 Hom.: 0 Cov.: 33 AF XY: 0.000175 AC XY: 13 AN XY: 74386

Gnomad4 AFR AF: 0.000145

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000578

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000323

Gnomad4 OTH AF: 0.000478

Alfa AF: 0.0000694 Hom.: 0

Bravo AF: 0.000204

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Amyotrophic lateral sclerosis type 1 Uncertain:1

Jan 13, 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	-0.75
CADD	Benign	1.1
DANN	Benign	0.87

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

Publications

LitVar

Other links and lift over

dbSNP: rs16988395; hg19: chr21-33032028;