VPS4A

Chr 16AD

vacuolar protein sorting 4 homolog A

Also known as: CIMDAG, SKD1, SKD1A, SKD2, VPS4, VPS4-1

NCBI Gene: 27183 ENSG00000132612 UniProt: Q9UN37

The protein encoded by this gene is a member of the AAA protein family (ATPases associated with diverse cellular activities), and is the homolog of the yeast Vps4 protein. In humans, two paralogs of the yeast protein have been identified. The former share a high degree of aa sequence similarity with each other, and also with yeast Vps4 and mouse Skd1 proteins. The mouse Skd1 (suppressor of K+ transport defect 1) has been shown to be really an yeast Vps4 ortholog. Functional studies indicate that both human paralogs associate with the endosomal compartments, and are involved in intracellular protein trafficking, similar to Vps4 protein in yeast. The gene encoding this paralog has been mapped to chromosome 16; the gene for the other resides on chromosome 18. [provided by RefSeq, Jul 2008]

Primary Disease Associations & Inheritance

CIMDAG syndromeMIM #619273

Active trials

Pathogenic / LP

ClinVar variants

Pubs (1 yr)

2.7

Missense Z

0.35

LOEUF· LoF intolerant

Clinical Summary— VPS4A

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Population Constraint (gnomAD)

Highly constrained gene — heterozygous loss-of-function variants are very rare in the population (pLI 0.94). One damaged copy is likely sufficient to cause disease.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

LoF intolerant — likely haploinsufficient

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.

0.35LOEUF

pLI 0.945

Z-score 3.79

OE 0.13 (0.06–0.35)

Highly constrained

Highly LoF-intolerant (top ~10% 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.

2.68Z-score

OE missense 0.54 (0.47–0.62)

147 obs / 271.5 exp

Mild constraint

Moderately missense-constrained (top ~2.5%)

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.0.13 (0.06–0.35)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.54 (0.47–0.62)

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.1.18

0≤1.21.6

LoF obs/exp: 3 / 22.4Missense obs/exp: 147 / 271.5Syn Z: -1.54

0.5476th %ile

GOF

0.4184th %ile

LOF

0.56top 25%

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

LOFLOEUF 0.35

DN1 literature citation

Literature Evidence

DNIn cultured cells, overexpression of VPS4A mutants caused enlarged endosomal vacuoles resembling those induced by expression of known dominant-negative ATPase-defective forms of VPS4A.PMID:33186545

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312. Mechanism ranking also informed by gnomAD constraint, ClinVar, and ClinGen data.