18-51030711-ACGGCGGCGGCGG-ACGGCGGCGGCGGCGGCGG

Variant names:

• chr18-51030711-A-ACGGCGG
• rs533316618
• NM_005359.6:c.-128+105_-128+110dupGGCGGC

Variant summary

Our verdict is Benign. The variant received -8 ACMG points: 0P and 8B. BS1 BS2

The NM_005359.6(SMAD4):​c.-128+105_-128+110dupGGCGGC variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000658 in 148,848 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: 𝑓 0.00066 (0 hom., cov: 31)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SMAD4 NM_005359.6 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.545
• Publications: 1 publications found

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]

SMAD4 Gene-Disease associations (from GenCC):

• juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Genomics England PanelApp, G2P, PanelApp Australia
• Myhre syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Orphanet, G2P, Labcorp Genetics (formerly Invitae)
• generalized juvenile polyposis/juvenile polyposis coli

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp
• juvenile polyposis syndrome

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• familial thoracic aortic aneurysm and aortic dissection

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary hemorrhagic telangiectasia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• pulmonary arterial hypertension

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ENSG00000267699 (HGNC:):

ACMG classification

Our verdict: Benign. The variant received -8 ACMG points.

• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.000658 (98/148848) while in subpopulation AFR AF = 0.00206 (84/40874). AF 95% confidence interval is 0.0017. There are 0 homozygotes in GnomAd4. There are 49 alleles in the male GnomAd4 subpopulation. Median coverage is 31. This position passed quality control check.
• BS2: High AC in GnomAd4 at 98 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMAD4	NM_005359.6	c.-128+105_-128+110dupGGCGGC		intron_variant	Intron 1 of 11	ENST00000342988.8	NP_005350.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMAD4	ENST00000342988.8	c.-128+88_-128+89insCGGCGG		intron_variant	Intron 1 of 11	5	NM_005359.6	ENSP00000341551.3
ENSG00000267699	ENST00000590722.2	n.158-16209_158-16208insCGGCGG		intron_variant	Intron 2 of 8	2		ENSP00000465737.1

Frequencies

GnomAD3 genomes AF: 0.000659 AC: 98 AN: 148740 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.00206

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000333

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000397

Gnomad SAS AF: 0.000419

Gnomad FIN AF: 0.000104

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000599

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1460 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 878

African (AFR) AF: 0.00 AC: 0 AN: 4

American (AMR) AF: 0.00 AC: 0 AN: 6

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 4

East Asian (EAS) AF: 0.00 AC: 0 AN: 58

South Asian (SAS) AF: 0.00 AC: 0 AN: 848

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 4

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 8

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 502

Other (OTH) AF: 0.00 AC: 0 AN: 26

GnomAD4 genome AF: 0.000658 AC: 98 AN: 148848 Hom.: 0 Cov.: 31 AF XY: 0.000675 AC XY: 49 AN XY: 72640

African (AFR) AF: 0.00206 AC: 84 AN: 40874

American (AMR) AF: 0.000332 AC: 5 AN: 15042

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3416

East Asian (EAS) AF: 0.000398 AC: 2 AN: 5022

South Asian (SAS) AF: 0.000419 AC: 2 AN: 4772

European-Finnish (FIN) AF: 0.000104 AC: 1 AN: 9638

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 290

European-Non Finnish (NFE) AF: 0.0000599 AC: 4 AN: 66814

Other (OTH) AF: 0.00 AC: 0 AN: 2074

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.000763

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.55

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs533316618; hg19: chr18-48557081;