PAFAH1B1

Chr 17AD

platelet activating factor acetylhydrolase 1b regulatory subunit 1

Also known as: LIS1, LIS2, MDCR, MDS, NudF, PAFAH

NCBI Gene: 5048 ENSG00000007168 UniProt: P43034

This locus was identified as encoding a gene that when mutated or lost caused the lissencephaly associated with Miller-Dieker lissencephaly syndrome. This gene encodes the non-catalytic alpha subunit of the intracellular Ib isoform of platelet-activating factor acteylhydrolase, a heterotrimeric enzyme that specifically catalyzes the removal of the acetyl group at the SN-2 position of platelet-activating factor (identified as 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine). Two other isoforms of intracellular platelet-activating factor acetylhydrolase exist: one composed of multiple subunits, the other, a single subunit. In addition, a single-subunit isoform of this enzyme is found in serum. [provided by RefSeq, Apr 2009]

Primary Disease Associations & Inheritance

Lissencephaly 1MIM #607432

Subcortical laminar heterotopiaMIM #607432

UniProtSubcortical band heterotopia

UniProtMiller-Dieker lissencephaly syndrome

390

ClinVar variants

Pathogenic / LP

1.00

pLI score· haploinsufficient

Active trials

Clinical Summary— PAFAH1B1

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Population Constraint (gnomAD)

Highly constrained gene — heterozygous loss-of-function variants are very rare in the population (pLI 1.00). One damaged copy is likely sufficient to cause disease.

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ClinVar Variants

82 Pathogenic / Likely Pathogenic· 138 VUS of 390 total submissions

Some data sources returned errors (1)

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Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Dual constrained — LoF & missense intolerant

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.

0.11LOEUF

pLI 1.000

Z-score 4.89

OE 0.00 (0.00–0.11)

Highly constrained

Among the most LoF-intolerant genes (~top 3%)

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.

3.53Z-score

OE missense 0.35 (0.29–0.42)

81 obs / 232.3 exp

Constrained

Highly missense-constrained (top ~0.1%)

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.0.00 (0.00–0.11)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.35 (0.29–0.42)

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.0.87

0≤1.21.6

LoF obs/exp: 0 / 27.9Missense obs/exp: 81 / 232.3Syn Z: 0.91