IDO2

Chr 8

indoleamine 2,3-dioxygenase 2

Also known as: INDOL1

NCBI Gene: 169355 ENSG00000188676 UniProt: Q6ZQW0 OMIM: 612129

Along with the enzymes encoded by the INDO (MIM 147435) and TDO2 (MIM 191070) genes, the enzyme encoded by the INDOL1 gene metabolizes tryptophan in the kynurenine pathway (Ball et al., 2007 [PubMed 17499941]).[supplied by OMIM, Feb 2011]

OMIM Research

OMIM ResearchGenerating clinical summary…

Active trials

Pubs (1 yr)

—

P/LP submissions

—

P/LP missense

1.25

LOEUF

Mechanism· predicted

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?

1.25LOEUF

pLI 0.000

Z-score 0.75

OE 0.81 (0.54–1.25)

Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?

-0.46Z-score

OE missense 1.09 (0.98–1.21)

234 obs / 215.2 exp

Tolerant

Tolerant to missense variation

Observed / Expected Ratios?

LoF OE?0.81 (0.54–1.25)

0≤0.351.4

Missense OE?1.09 (0.98–1.21)

0≤0.61.4

Synonymous OE?1.05

0≤1.21.6

LoF obs/exp: 15 / 18.5Missense obs/exp: 234 / 215.2Syn Z: -0.37

Background carrier burden — how many people carry a rare variant somewhere in IDO2?

gnomAD v4 · ~731k individuals · PASS only

Rare means allele frequency under

Rare missense

1 in 92

585 rare PASS variants

Rare truncating (LoF)

1 in 540

98 rare PASS variants

Rare synonymous (reference)

1 in 280

227 rare PASS variants

Truncating variants are far rarer here than missense — that gap, in human units, is what constraint means for IDO2. 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 120	1 in 1,200
South Asian	~43k	1 in 110	1 in 670
Remaining (unassigned)	~30k	1 in 70	1 in 260
European (Finnish)	~27k	1 in 600	≈ 1 in 8,800
Admixed American	~22k	1 in 79	1 in 390
African / African American	~21k	1 in 100	1 in 920
East Asian	~20k	1 in 140	1 in 820
Ashkenazi Jewish	~13k	1 in 1,000	≈ 1 in 13,000
Middle Eastern	~2,884	1 in 82	≈ 1 in 960

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): 7 of 10 coding exons well covered in gnomAD exomes; exons 3, 5, 9 marginal. Genomes: all 10.? see exons ↓