TTC1

Chr 5

tetratricopeptide repeat domain 1

Also known as: TPR1

This gene encodes an adapter protein that binds to G protein subunits to activate Ras signaling and also functions as a co-chaperone in the HSP70 protein folding pathway. Mutations in TTC1 cause autosomal recessive intellectual disability with seizures and spasticity. The gene shows minimal constraint against loss-of-function variants, consistent with its recessive inheritance pattern.

OMIMResearchSummary from RefSeq, UniProt
DNmechanismLOEUF 1.11
Clinical SummaryTTC1
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
1.11LOEUF
pLI 0.000
Z-score 1.23
OE 0.67 (0.421.11)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint
0.66Z-score
OE missense 0.85 (0.730.98)
125 obs / 147.5 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.67 (0.421.11)
00.351.4
Missense OE0.85 (0.730.98)
00.61.4
Synonymous OE0.93
01.21.6
LoF obs/exp: 11 / 16.4Missense obs/exp: 125 / 147.5Syn Z: 0.44
DN
0.78top 25%
GOF
0.6053th %ile
LOF
0.2191th %ile

The highest-scoring mechanism for this gene is dominant-negative.

DNprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

TTC1 · protein map & ClinVar variants

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

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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Clinical Literature
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