VPS33A

Chr 12AR

VPS33A core subunit of CORVET and HOPS complexes

Also known as: MPSPS

NCBI Gene: 65082 ENSG00000139719 UniProt: Q96AX1

This gene encodes a tethering protein and a core subunit of the homotypic fusion and protein sorting (HOPS) complex. The HOPS complex and a second endosomal tethering complex called the class C core vacuole/endosome tethering (CORVET) complex, perform diverse functions in endocytosis including membrane tethering, RabGTPase interaction, activation and proofreading of synaptic-soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) assembly to drive membrane fusion, and endosome-to-cytoskeleton attachment. The HOPS complex controls endosome maturation as well as endosome traffic to the lysosome. This complex is essential for vacuolar fusion and is required for adaptor protein complex 3-dependent transport from the golgi to the vacuole. The encoded protein belongs to the Sec1/Munc18 (SM) family of SNARE-mediated membrane fusion regulators. Naturally occurring mutations in this gene are associated with a novel mucopolysaccharidosis-like disease. [provided by RefSeq, Apr 2017]

Primary Disease Associations & Inheritance

Mucopolysaccharidosis-plus syndromeMIM #617303

287

ClinVar variants

Pathogenic / LP

0.18

pLI score

Active trials

Clinical Summary— VPS33A

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Gene-Disease Validity (ClinGen)

mucopolysaccharidosis-plus syndrome · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

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Population Constraint (gnomAD)

Constrained for loss-of-function variants (OE-LoF 0.24) despite low pLI — interpret in context.

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ClinVar Variants

21 Pathogenic / Likely Pathogenic· 109 VUS of 287 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Moderate LoF intolerance

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.

0.44LOEUF

pLI 0.182

Z-score 4.01

OE 0.24 (0.14–0.44)

Moderately constrained

More LoF-intolerant than ~75% of genes

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.

1.64Z-score

OE missense 0.75 (0.68–0.83)

263 obs / 349.0 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.0.24 (0.14–0.44)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.75 (0.68–0.83)

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.1.07

0≤1.21.6

LoF obs/exp: 8 / 32.8Missense obs/exp: 263 / 349.0Syn Z: -0.63