HADHB

Chr 2AR

hydroxyacyl-CoA dehydrogenase trifunctional multienzyme complex subunit beta

Also known as: ECHB, MSTP029, MTPB, MTPD, MTPD2, TP-BETA

NCBI Gene: 3032 ENSG00000138029 UniProt: P55084

This gene encodes the beta subunit of the mitochondrial trifunctional protein, which catalyzes the last three steps of mitochondrial beta-oxidation of long chain fatty acids. The mitochondrial membrane-bound heterocomplex is composed of four alpha and four beta subunits, with the beta subunit catalyzing the 3-ketoacyl-CoA thiolase activity. The encoded protein can also bind RNA and decreases the stability of some mRNAs. The genes of the alpha and beta subunits of the mitochondrial trifunctional protein are located adjacent to each other in the human genome in a head-to-head orientation. Mutations in this gene result in trifunctional protein deficiency. Alternatively spliced transcript variants encoding different isoforms have been described. [provided by RefSeq, Jul 2013]

Primary Disease Associations & Inheritance

Mitochondrial trifunctional protein deficiency 2MIM #620300

547

ClinVar variants

113

Pathogenic / LP

0.00

pLI score

Active trials

Clinical Summary— HADHB

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Gene-Disease Validity (ClinGen)

mitochondrial trifunctional protein deficiency · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

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Population Constraint (gnomAD)

Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.

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ClinVar Variants

113 Pathogenic / Likely Pathogenic· 140 VUS of 547 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.

1.04LOEUF

pLI 0.000

Z-score 1.39

OE 0.72 (0.51–1.04)

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.

0.65Z-score

OE missense 0.89 (0.80–0.99)

234 obs / 263.7 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.0.72 (0.51–1.04)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.89 (0.80–0.99)

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.0.95

0≤1.21.6

LoF obs/exp: 21 / 29.1Missense obs/exp: 234 / 263.7Syn Z: 0.39