TTLL8

Chr 22

tubulin tyrosine ligase like 8

NCBI Gene: 164714ENSG00000138892UniProt: A6PVC2

Predicted to enable protein-glycine ligase activity, initiating. Predicted to be involved in several processes, including axoneme assembly; flagellated sperm motility; and protein polyglycylation. Predicted to act upstream of or within cilium assembly. Predicted to be located in cilium. Predicted to be active in axoneme; microtubule cytoskeleton; and sperm flagellum. [provided by Alliance of Genome Resources, Jul 2025]

153
ClinVar variants
137
Pathogenic / LP
0.00
pLI score
0
Active trials
Clinical Summary— TTLL8
⚡
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
📋
ClinVar Variants
137 Pathogenic / Likely Pathogenic· 12 VUS of 153 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Tolerant — LoF & missense variants common in population
LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.
1.03LOEUF
pLI 0.000
Z-score 1.42
OE 0.75 (0.55–1.03)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.
0.35Z-score
OE missense 0.95 (0.88–1.03)
451 obs / 472.5 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.
LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.75 (0.55–1.03)
0≤0.351.4
Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.95 (0.88–1.03)
0≤0.61.4
Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.0.98
0≤1.21.6
LoF obs/exp: 27 / 36.2Missense obs/exp: 451 / 472.5Syn Z: 0.28

ClinVar Variant Classifications

153 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic136
Likely Pathogenic1
VUS12
Likely Benign3
Benign1
136
Pathogenic
1
Likely Pathogenic
12
VUS
3
Likely Benign
1
Benign

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories· variant type breakdown unavailable

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
————136
Likely Pathogenic
————1
VUS
————12
Likely Benign
————3
Benign
————1
Total—153

Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

TTLL8 · protein map & ClinVar variants

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

OMIM — Genotype-Phenotype Relationships

1 OMIM entry

OMIM
Clinical Literature
Landmark / reviewRecent case evidence
Key Publications
Landmark & review papers · by relevance
PubMed
Top 10 resultsSearch PubMed ↗
Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC
Top 5 resultsSearch Europe PMC ↗

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →

External Resources

Links to major genomics databases and tools