IFT27

Chr 22AR

intraflagellar transport 27

Also known as: BBS19, CFAP156, FAP156, RABL4, RAYL

NCBI Gene: 11020ENSG00000100360UniProt: Q9BW83

This gene encodes a GTP-binding protein that is a core component of the intraflagellar transport complex B. Characterization of the similar Chlamydomonas protein indicates a function in cell cycle control. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, Jan 2012]

Primary Disease Associations & Inheritance

Bardet-Biedl syndrome 19MIM #615996
AR
222
ClinVar variants
31
Pathogenic / LP
0.00
pLI score
1
Active trials
Clinical Summary— IFT27
⚡
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
📋
ClinVar Variants
31 Pathogenic / Likely Pathogenic· 77 VUS of 222 total submissions
💊
Clinical Trials
1 active or recruiting trial — potential therapeutic options may be available

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.
1.41LOEUF
pLI 0.000
Z-score 0.58
OE 0.81 (0.49–1.41)
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.
0.22Z-score
OE missense 0.94 (0.80–1.11)
98 obs / 104.2 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.0.81 (0.49–1.41)
0≤0.351.4
Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.94 (0.80–1.11)
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.0.86
0≤1.21.6
LoF obs/exp: 9 / 11.1Missense obs/exp: 98 / 104.2Syn Z: 0.73

ClinVar Variant Classifications

222 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic26
Likely Pathogenic5
VUS77
Likely Benign87
Benign8
Conflicting10
26
Pathogenic
5
Likely Pathogenic
77
VUS
87
Likely Benign
8
Benign
10
Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
4
3
19
0
26
Likely Pathogenic
3
1
1
0
5
VUS
1
64
9
3
77
Likely Benign
0
3
47
37
87
Benign
0
2
4
2
8
Conflicting
—10
Total8738042213

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

IFT27 · protein map & ClinVar variants

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

Gene2Phenotype Curations

IFT27-related Bardet-Biedl syndrome

limited
ARUndeterminedAltered Gene Product Structure
Eye
G2P ↗
missense variantinframe deletioninframe insertion

Gene2Phenotype curations · DECIPHER consortium patient cohort (public variants) · deciphergenomics.org

OMIM — Genotype-Phenotype Relationships

1 OMIM entry

OMIM

Bardet-Biedl syndrome 19

MIM #615996

Molecular basis of disorder known

Autosomal recessive
Clinical Literature
Landmark / reviewRecent case evidence
Key Publications
Landmark & review papers · by relevance
PubMed
IFT27 regulates the long-term maintenance of photoreceptor outer segments in zebrafish.
Han S et al.·Gene
2024Functional
Loss of function IFT27 variants associated with an unclassified lethal fetal ciliopathy with renal agenesis.
Quélin C et al.·Am J Med Genet A
2018Case report
Biallelic Variants in Seven Different Genes Associated with Clinically Suspected Bardet-Biedl Syndrome.
Nawaz H et al.·Genes (Basel)
2023
Leucine zipper transcription factor-like 1 (LZTFL1), an intraflagellar transporter protein 27 (IFT27) associated protein, is required for normal sperm function and male fertility.
Huang Q et al.·Dev Biol
2021
Compound heterozygous IFT81 variations in a skeletal ciliopathy patient cause Bardet-Biedl syndrome-like ciliary defects.
Tasaki K et al.·Hum Mol Genet
2023Case report
Combining targeted panel-based resequencing and copy-number variation analysis for the diagnosis of inherited syndromic retinopathies and associated ciliopathies.
Sanchez-Navarro I et al.·Sci Rep
2018
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
Morbid ObesityBariatric SurgeryTelerehabilitation

Exercise to Fight Obesity

RECRUITING
NCT06934681Phase NAInstituto de Investigacion Sanitaria La FeStarted 2025-05-19
Usual Care GroupControlled exercise with telerehabilitation

External Resources

Links to major genomics databases and tools