STAG1

Chr 3AD

STAG1 cohesin complex component

Also known as: MRD47, SA1, SCC3A

Encodes a component of the cohesin complex that maintains sister chromatid cohesion during cell division. Mutations cause autosomal dominant intellectual developmental disorder with onset in early childhood. The gene is highly constrained against loss-of-function variants, indicating that such variants are likely pathogenic when they occur.

OMIMResearchSummary from RefSeq, OMIM, UniProt
LOFmechanismADLOEUF 0.121 OMIM phenotype
Clinical SummarySTAG1
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Gene-Disease Validity (ClinGen)
complex neurodevelopmental disorder · ADDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Highly constrained gene — heterozygous loss-of-function variants are very rare in the population (pLI 1.00). One damaged copy is likely sufficient to cause disease.
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Clinical Trials
1 active or recruiting trial — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Dual constrained — LoF & missense intolerant
LoF Constraint
0.12LOEUF
pLI 1.000
Z-score 7.69
OE 0.05 (0.030.12)
Highly constrained

Among the most LoF-intolerant genes (~top 3%)

Missense Constraint
4.44Z-score
OE missense 0.51 (0.470.56)
338 obs / 658.9 exp
Constrained

Highly missense-constrained (top ~0.1%)

Observed / Expected Ratios
LoF OE0.05 (0.030.12)
00.351.4
Missense OE0.51 (0.470.56)
00.61.4
Synonymous OE1.08
01.21.6
LoF obs/exp: 4 / 76.7Missense obs/exp: 338 / 658.9Syn Z: -0.89
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitiveSTAG1-related syndromic intellectual disabilityLOFAD
DN
0.3196th %ile
GOF
0.4085th %ile
LOF
0.69top 10%

The highest-scoring mechanism for this gene is loss-of-function (haploinsufficiency).

LOFprediction above median · 1 literature citation · LOEUF 0.12

Literature Evidence

LOFFunctional studies of the variants and studies of patient cells were not performed, but Lehalle et al. (2017) postulated that the neurodevelopmental phenotype is caused by STAG1 haploinsufficiency with a putative disruptive effect on transcriptional regulation.PMID:28119487

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312. Mechanism ranking also informed by gnomAD constraint, ClinVar, and ClinGen data.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

STAG1 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold
Clinical Literature
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