Is PIGO p.Pro422= (c.1266G>A) pathogenic?

PIGO p.Pro422= (c.1266G>A) is classified Likely benign in PIGO (ClinVar, Single submitter, 1 submitter; last evaluated 2022-11-22). Very rare (popmax 0.00267%, afr); Associated with hyperphosphatasia with intellectual disability syndrome 2.

What condition is associated with PIGO p.Pro422= (c.1266G>A)?

PIGO p.Pro422= (c.1266G>A) is associated with hyperphosphatasia with intellectual disability syndrome 2 (ClinVar).

How common is PIGO p.Pro422= (c.1266G>A) in the general population?

PIGO p.Pro422= (c.1266G>A) is very rare (popmax 0.00267%, afr) (gnomAD).

PIGO p.Pro422=

Q: How is Hyperphosphatasia-intellectual disability syndrome inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

c.1266G>A · rs758742085 · VCV745229

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00267%, afr)

Conditions

hyperphosphatasia with intellectual disability syndrome 2

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 0.73	GERP 0.63, phastCons 0.15
Overall
CADD	6.407	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00267% African / African-American · 2/74,946 alleles

Filtering AF 0.000443% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000166%

Overall 0.000558% 9/1,614,122 alleles · very rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.00267%	37,473
East Asian	0.00223%	44,900
South Asian	0.0022%	45,542
Remaining individualsnot grpmax-eligible	0.0016%	62,486
European (non-Finnish)	0.000254%	393,354

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: PIGO
Protein: p.Pro422=
Coding: c.1266G>A
MANE Select: NM_032634
dbSNP: rs758742085
Type: single nucleotide variant
Location: chr9:35092621 (GRCh38)
Gene constraint: LOEUF 0.89 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 82.57

Full PIGO gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

hyperphosphatasia with intellectual disability syndrome 2 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Hyperphosphatasia-intellectual disability syndrome (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal

Similar variants

PIGO c.2648-1G>A Likely pathogenic ★★ same condition
PIGO c.3069+2T>C Likely pathogenic ★★ same condition
PIGO c.3069+5G>A Pathogenic/Likely pathogenic ★★ same condition
PIGO p.Arg119Trp Likely pathogenic ★★ ⚠ same condition
PIGO p.Arg122Ter Pathogenic/Likely pathogenic ★★ same condition
PIGO p.Arg376Ter Pathogenic/Likely pathogenic ★★ same condition
PIGO p.Arg802Ter Pathogenic/Likely pathogenic ★★ same condition
PIGO p.Gln372Ter Pathogenic ★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/pigo-p-pro422 (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown