1-183515948-A-G

Variant names:

• chr1-183515948-A-G
• rs1223104099
• NM_001375584.1:c.136A>G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_001394144.1(SMG7):​c.-236A>G variant causes a 5 prime UTR premature start codon gain change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,196 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SMG7 NM_001394144.1 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.78

Genes affected

SMG7 (HGNC:16792): (SMG7 nonsense mediated mRNA decay factor) This gene encodes a protein that is essential for nonsense-mediated mRNA decay (NMD); a process whereby transcripts with premature termination codons are targeted for rapid degradation by a mRNA decay complex. The mRNA decay complex consists, in part, of this protein along with proteins SMG5 and UPF1. The N-terminal domain of this protein is thought to mediate its association with SMG5 or UPF1 while the C-terminal domain interacts with the mRNA decay complex. This protein may therefore couple changes in UPF1 phosphorylation state to the degradation of NMD-candidate transcripts. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Aug 2011]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMG7	NM_001375584.1	c.136A>G	p.Thr46Ala	missense_variant	Exon 3 of 23	ENST00000688051.1	NP_001362513.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMG7	ENST00000688051.1	c.136A>G	p.Thr46Ala	missense_variant	Exon 3 of 23		NM_001375584.1	ENSP00000510175.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461196 Hom.: 0 Cov.: 29 AF XY: 0.00000138 AC XY: 1 AN XY: 726944

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Nov 12, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.136A>G (p.T46A) alteration is located in exon 3 (coding exon 3) of the SMG7 gene. This alteration results from a A to G substitution at nucleotide position 136, causing the threonine (T) at amino acid position 46 to be replaced by an alanine (A). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.31
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.030
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Benign	0.042	.;T;.;T;T;.;.;T
Eigen	Uncertain	0.24
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D;D;D;D;D;D;D;D
M_CAP	Benign	0.0089	T
MetaRNN	Uncertain	0.47	T;T;T;T;T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.90	.;.;.;.;L;L;L;.
PrimateAI	Pathogenic	0.90	D
PROVEAN	Benign	-1.3	N;D;N;N;N;N;N;.
REVEL	Uncertain	0.30
Sift	Benign	0.072	T;D;D;T;T;T;T;.
Sift4G	Benign	0.48	T;T;T;T;T;T;T;.
Polyphen		0.84	P;.;.;.;P;.;P;.
Vest4		0.73
MutPred		0.35		Loss of ubiquitination at K71 (P = 0.1576);Loss of ubiquitination at K71 (P = 0.1576);.;.;.;.;.;.;
MVP		0.80
MPC		1.7
ClinPred		0.59	D
GERP RS		5.7
Varity_R		0.25
gMVP		0.30

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: rs1223104099; hg19: chr1-183485083;