TMEM38B

Chr 9AR

transmembrane protein 38B

Also known as: C9orf87, D4Ertd89e, OI14, TRIC-B, TRICB, bA219P18.1

NCBI Gene: 55151 ENSG00000095209 UniProt: Q9NVV0

This gene encodes an intracellular monovalent cation channel that functions in maintenance of intracellular calcium release. Mutations in this gene may be associated with autosomal recessive osteogenesis. [provided by RefSeq, Oct 2012]

Primary Disease Associations & Inheritance

Osteogenesis imperfecta, type XIVMIM #615066

Active trials

Pathogenic / LP

ClinVar variants

Pubs (1 yr)

-0.1

Missense Z

0.80

LOEUF

Clinical Summary— TMEM38B

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Population Constraint (gnomAD)

Low constraint (pLI 0.02) — loss-of-function variants are relatively tolerated in the population.

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.

0.80LOEUF

pLI 0.020

Z-score 2.09

OE 0.38 (0.20–0.80)

Tolerant

Typical tolerance to LoF variation

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.

-0.05Z-score

OE missense 1.01 (0.89–1.15)

158 obs / 156.2 exp

Tolerant

Tolerant to missense variation

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.0.38 (0.20–0.80)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.1.01 (0.89–1.15)

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.1.14

0≤1.21.6

LoF obs/exp: 5 / 13.2Missense obs/exp: 158 / 156.2Syn Z: -0.84

0.7035th %ile

GOF

0.6541th %ile

LOF

0.3165th %ile

This gene has evidence for multiple mechanisms of pathogenicity (dominant-negative and gain-of-function). Both the Badonyi & Marsh prediction and the broader genomic evidence point to dominant-negative as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

DNprediction above median

GOFprediction 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.