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Gene

SMAD3

SMAD family member 3

Summary

Cytogenetic location
15q22.33
Coordinates
Chromosome 15: 67,065,602–67,195,169 (GRCh38)
Exons
9 exons across 129.6 kb
Protein
425 amino acids
Inheritance
Autosomal dominant
Also known as
JV15-2, HsT17436
Previous symbols
MADH3
MANE Select transcript
ENST00000327367.9NM_005902.4
Locus type
gene with protein product
  • Very high
  • Confident
  • Low
  • Very low

Reference genomeGRCh38

Positions on gene and variant pages follow this choice, in this browser.

Curated reports relevant to this gene

  • Loeys-Dietz Syndrome

    • Autosomal dominant

      Loeys-Dietz syndrome is a rare genetic connective tissue disorder characterized by a broad spectrum of craniofacial, vascular and skeletal manifestations with five genetic subtypes described forming a clinical continuum.

      • 3 GenCC submitters rate it definitive or strong
      • On the ACMG secondary findings list

  • Marfan Like Syndromes

    • Loeys-Dietz SyndromeAutosomal dominant

      Loeys-Dietz syndrome is a rare genetic connective tissue disorder characterized by a broad spectrum of craniofacial, vascular and skeletal manifestations with five genetic subtypes described forming a clinical continuum.

      • 3 GenCC submitters rate it definitive or strong
      • On the ACMG secondary findings list

Inheritance

Autosomal dominant
One changed copy, from either parent, is enough. A parent who has one passes it on to each child with a one-in-two chance.

How SMAD3 is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Stretches short reads find hard
  • Variants with a page
Chromosome 15, with a bracket where SMAD3 sits. SMAD3 and 5 genes near it on chromosome 15, from 66,630,386 to 67,630,385.Chromosome 1515q22.33p13p12p11.2p11.1q11.1q11.2q12q13.1q13.2q13.3q14q15.1q15.2q15.3q21.1q21.2q21.3q22.1q22.2q22.31q22.32q22.33q23q24.1q24.2q24.3q25.1q25.2q25.3q26.1q26.2q26.366.8 Mb67 Mb67.2 Mb67.4 Mb67.6 MbSMAD6: 66,701,224–66,782,860, forward strandSMAD6SMAD3: 67,065,602–67,195,169, forward strandSMAD3AAGAB: 67,200,462–67,255,195, reverse strandAAGABIQCH: 67,254,776–67,502,260, forward strandIQCHC15orf61: 67,521,105–67,530,146, forward strandC15orf61MAP2K5: 67,542,611–67,807,123, forward strandMAP2K5Diagram of SMAD3: 9 exons on the forward strand of chromosome 15Exon 1: 6 known disease-causing sitesExon 2: 11 known disease-causing sitesExon 3: 2 known disease-causing sitesExon 4: 1 known disease-causing siteExon 6: 14 known disease-causing sitesExon 7: 4 known disease-causing sitesExon 8: 5 known disease-causing sitesExon 9: 4 known disease-causing sitesExon 1: 67,065,602–67,066,360, 759 bases. 1 variant with a page in exon 1. List themExon 2: 67,164,895–67,165,088, 194 bases. 1 variant with a page in exon 2. List themExon 3: 67,165,253–67,165,384, 132 basesExon 4: 67,166,779–67,166,853, 75 basesExon 5: 67,170,554–67,170,604, 51 basesExon 6: 67,181,241–67,181,453, 213 bases. 1 variant with a page in exon 6. List themExon 7: 67,184,727–67,184,864, 138 basesExon 8: 67,187,365–67,187,509, 145 basesExon 9: 67,190,413–67,195,169, 4,757 bases. 1 variant with a page in exon 9. List them1595′3′

Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.

Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).

Nearby genes from Ensembl release 116, on GRCh38.

Exons make up 6.5 kb of the gene's 129.6 kb; 1,278 of those bases code for the protein.

How a genome test reads SMAD3

54

positions in SMAD3 where ClinVar classes a change as pathogenic or likely pathogenic

None of them falls in a region short reads find hard.

A whole genome covers all 129.6 kb of SMAD3, introns included, not only the 6.5 kb of exons.

Variants with a page (5)

The SMAD3 variants with a page here, most review stars first. Each page describes ClinVar's public record of the variant, never a result.

VariantHGVS c.Exon or intronPosition (GRCh38)ClinVar classificationReview status
c.3G>AExon 167,066,157Pathogenic/likely pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts
c.401-6G>AIntron 267,165,247Pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts
R90Cc.268C>TExon 267,164,956Likely pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts
R287Wc.859C>TExon 667,181,441Pathogenic/likely pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts
S423Nc.1268G>AExon 967,190,526Pathogenic/likely pathogenic2 stars out of 4 criteria provided, multiple submitters, no conflicts

Where this comes from

  • HGNC: the gene's symbol, name, other symbols and location.
  • MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
  • GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
  • The ACMG secondary findings list, SF v3.2.
  • ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
  • The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
  • Data release 2026.10.16-c6eea6bf.

Cite this page

APA

Dante Labs. (n.d.). SMAD3 gene: SMAD family member 3. Retrieved 17 October 2026, from https://dantelabs.com/genes/smad3

Vancouver

Dante Labs. SMAD3 gene: SMAD family member 3 [Internet]. [cited 17 October 2026]. Available from: https://dantelabs.com/genes/smad3

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