18-51030629-C-T

Position:

• chr18-51030629-C-T

Variant summary

Our verdict is Benign. Variant got -7 ACMG points: 0P and 7B. BP4_Moderate BS1_Supporting BS2

The NM_005359.6(SMAD4):​c.-128+6C>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000803 in 149,472 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000080 (0 hom., cov: 31)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SMAD4 NM_005359.6 splice_region, intron
• Scores: Splicing: ADA: 0.001702
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.230

Genes affected

SMAD4 (HGNC:6770): (SMAD family member 4) This gene encodes a member of the Smad family of signal transduction proteins. Smad proteins are phosphorylated and activated by transmembrane serine-threonine receptor kinases in response to transforming growth factor (TGF)-beta signaling. The product of this gene forms homomeric complexes and heteromeric complexes with other activated Smad proteins, which then accumulate in the nucleus and regulate the transcription of target genes. This protein binds to DNA and recognizes an 8-bp palindromic sequence (GTCTAGAC) called the Smad-binding element (SBE). The protein acts as a tumor suppressor and inhibits epithelial cell proliferation. It may also have an inhibitory effect on tumors by reducing angiogenesis and increasing blood vessel hyperpermeability. The encoded protein is a crucial component of the bone morphogenetic protein signaling pathway. The Smad proteins are subject to complex regulation by post-translational modifications. Mutations or deletions in this gene have been shown to result in pancreatic cancer, juvenile polyposis syndrome, and hereditary hemorrhagic telangiectasia syndrome. [provided by RefSeq, May 2022]

ENSG00000267699 (HGNC:):

ACMG classification

Verdict is Benign. Variant got -7 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.32).
• BS1: Variant frequency is greater than expected in population sas. gnomad4 allele frequency = 0.0000803 (12/149472) while in subpopulation SAS AF= 0.000414 (2/4828). AF 95% confidence interval is 0.0000729. There are 0 homozygotes in gnomad4. There are 8 alleles in male gnomad4 subpopulation. Median coverage is 31. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAd4 at 12 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SMAD4	NM_005359.6	c.-128+6C>T		splice_region_variant, intron_variant		ENST00000342988.8	NP_005350.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SMAD4	ENST00000342988.8	c.-128+6C>T		splice_region_variant, intron_variant		5	NM_005359.6	ENSP00000341551.3
ENSG00000267699	ENST00000590722.2	n.158-16291C>T		intron_variant		2		ENSP00000465737.1

Frequencies

GnomAD3 genomes AF: 0.0000803 AC: 12 AN: 149364 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.0000243

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000414

Gnomad FIN AF: 0.000103

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000120

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 472 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 246

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 AF: 0.0000803 AC: 12 AN: 149472 Hom.: 0 Cov.: 31 AF XY: 0.000110 AC XY: 8 AN XY: 72898

Gnomad4 AFR AF: 0.0000243

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000414

Gnomad4 FIN AF: 0.000103

Gnomad4 NFE AF: 0.000120

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000356 Hom.: 0

Bravo AF: 0.0000831

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Oct 11, 2024

Located in a regulatory region; in the absence of functional studies, the actual effect of this sequence change is unknown; In silico analysis indicates that this variant does not alter splicing; Has not been previously published as pathogenic or benign to our knowledge; No data available from control populations to assess the frequency of this variant -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

curation

Sema4, Sema4

Aug 07, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.32
CADD	Benign	19
DANN	Benign	0.97
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.3

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.0017
dbscSNV1_RF	Benign	0.020
SpliceAI score (max)		0.020		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: rs1023427434; hg19: chr18-48556999;