17-2061620-C-T

Position:

• chr17-2061620-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_017575.5(SMG6):​c.4132G>A​(p.Glu1378Lys) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SMG6 NM_017575.5 missense, splice_region
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.73

Genes affected

SMG6 (HGNC:17809): (SMG6 nonsense mediated mRNA decay factor) This gene encodes a component of the telomerase ribonucleoprotein complex responsible for the replication and maintenance of chromosome ends. The encoded protein also plays a role in the nonsense-mediated mRNA decay (NMD) pathway, providing the endonuclease activity near the premature translation termination codon that is needed to initiate NMD. Alternatively spliced transcript variants encoding distinct protein isoforms have been described. [provided by RefSeq, Feb 2014]

HIC1 (HGNC:4909): (HIC ZBTB transcriptional repressor 1) This gene functions as a growth regulatory and tumor repressor gene. Hypermethylation or deletion of the region of this gene have been associated with tumors and the contiguous-gene syndrome, Miller-Dieker syndrome. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, Sep 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.18018577).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMG6	NM_017575.5	c.4132G>A	p.Glu1378Lys	missense_variant, splice_region_variant	19/19	ENST00000263073.11
HIC1	NM_006497.4	c.*2785C>T		3_prime_UTR_variant	2/2	ENST00000619757.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMG6	ENST00000263073.11	c.4132G>A	p.Glu1378Lys	missense_variant, splice_region_variant	19/19	1	NM_017575.5	P1
HIC1	ENST00000619757.5	c.*2785C>T		3_prime_UTR_variant	2/2	1	NM_006497.4	P4

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1418426 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 701644

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 12, 2024

The c.4132G>A (p.E1378K) alteration is located in exon 19 (coding exon 19) of the SMG6 gene. This alteration results from a G to A substitution at nucleotide position 4132, causing the glutamic acid (E) at amino acid position 1378 to be replaced by a lysine (K). 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	Benign	-0.10	T
BayesDel_noAF	Benign	-0.39
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.034	T;.;.
Eigen	Benign	0.19
Eigen_PC	Uncertain	0.32
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Benign	0.80	T;.;T
M_CAP	Benign	0.0092	T
MetaRNN	Benign	0.18	T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.23	N;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-0.81	N;.;N
REVEL	Benign	0.12
Sift	Benign	0.53	T;.;T
Sift4G	Benign	0.42	T;T;T
Polyphen		0.67	P;.;.
Vest4		0.19
MutPred		0.47		Loss of helix (P = 0.0033);.;.;
MVP		0.42
MPC		0.25
ClinPred		0.87	D
GERP RS		5.0
Varity_R		0.18
gMVP		0.39

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

LitVar

Other links and lift over

dbSNP: rs1221804374; hg19: chr17-1964914;