CIBAR1

Chr 8

CBY1 interacting BAR domain containing 1

Also known as: BARMR1, FAM92A, FAM92A1, PAPA9

NCBI Gene: 137392 ENSG00000188343 UniProt: A1XBS5

The CIBAR1 protein regulates mitochondrial ultrastructure by maintaining cristae organization and plays a crucial role in ciliogenesis and limb development through its phospholipid binding activity and ability to induce membrane curvature. Mutations cause postaxial polydactyly type A9 with autosomal recessive inheritance. The gene shows low constraint to loss-of-function variants, suggesting tolerance to complete protein loss.

ResearchSummary from RefSeq, OMIM, UniProt

Enables phospholipid binding activity. Involved in several processes, including inner mitochondrial membrane organization; limb morphogenesis; and membrane tubulation. Located in several cellular components, including centriole; ciliary base; and mitochondrial crista. [provided by Alliance of Genome Resources, Jul 2025]

ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

UniProtPolydactyly, postaxial, A9

Active trials

Pubs (1 yr)

—

P/LP submissions

—

P/LP missense

1.10

LOEUF

Multiple*

Mechanism· predicted

Some data sources returned errors (1)

omim: Error: OMIM fetch failed: 429

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?

1.10LOEUF

pLI 0.000

Z-score 1.21

OE 0.71 (0.47–1.10)

Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?

0.97Z-score

OE missense 0.77 (0.66–0.91)

113 obs / 145.9 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?

LoF OE?0.71 (0.47–1.10)

0≤0.351.4

Missense OE?0.77 (0.66–0.91)

0≤0.61.4

Synonymous OE?0.91

0≤1.21.6

LoF obs/exp: 14 / 19.8Missense obs/exp: 113 / 145.9Syn Z: 0.48

Background carrier burden — how many people carry a rare variant somewhere in CIBAR1?

gnomAD v4 · ~731k individuals · PASS only

Rare means allele frequency under

Rare missense

1 in 180

360 rare PASS variants

Rare truncating (LoF)

1 in 1,900

83 rare PASS variants

Rare synonymous (reference)

1 in 380

147 rare PASS variants

Truncating variants are far rarer here than missense — that gap, in human units, is what constraint means for CIBAR1. A background rate for each class, not the frequency of any particular variant; thin-coverage exons undercount.

By genetic ancestry · 9 gnomAD groups · rare = under 0.1% in that group

Group	People	Missense	Truncating
European (non-Finnish)	~556k	1 in 260	1 in 1,200
South Asian	~43k	1 in 100	1 in 1,400
Remaining (unassigned)	~30k	1 in 130	1 in 2,000
European (Finnish)	~27k	1 in 760	≈ 1 in 13,000
Admixed American	~22k	1 in 240	1 in 530
African / African American	~21k	1 in 110	1 in 560
East Asian	~20k	1 in 160	1 in 560
Ashkenazi Jewish	~13k	1 in 660	≈ 1 in 13,000
Middle Eastern	~2,884	1 in 180	none seen

Each group is summed over the variants that are rare in that group. Grey ≈ figures rest on fewer than five expected carriers — too few to distinguish groups. Differences mostly reflect how many people were sampled and how much variation each ancestry carries, not disease risk.

Exome coverage (gnomAD): 4 of 9 coding exons well covered in gnomAD exomes; exons 1, 3, 5, 7, 9 marginal. Genomes: all 9.? see exons ↓