PAH p.Pro275Ser
c.823C>T · rs62508691 · VCV102853
ClinGen expert panel — Phenylketonuria VCEP
Pathogenic for phenylketonuria. Applied ACMG criteria (verbatim):
PM2 PP4_Moderate PM3_Strong PP3 PM5
Curation rationale (ClinGen, verbatim)
The c.823C>T (p.Pro275Ser) variant in PAH is absent from all population databases, and is in the same codon as two other likely pathogenic variants. In silico algorithms agree on a damaging effect. It has been identified in trans with two independent pathogenic variants (R408W and c.669delC; PMID: 20123475, 24705691), and a defect in BH4 metabolism was excluded as a cause of elevated phenylalanine in multiple patients. In summary, this variant meets criteria to be classified as pathogenic for PAH. PAH-specific ACMG/AMP criteria applied: PM3_strong, PM2, PP4_Moderate, PM5, PP3.
ClinGen Evidence Repository → · reported verbatim, not re-tallied by Sugi Variant.
Computational evidence
| Protein change | ||
| AlphaMissense | 0.8245 | likely pathogenic ✓ concordant with ClinVar |
|---|---|---|
| REVEL | 0.954 | strongly pathogenic-leaning |
| SaProt | LLR -12.10 | damaging |
| ⇒ AlphaMissense, REVEL and SaProt all call this damaging. | ||
| Splicing | ||
| SpliceAI | — | not assessed · no allele here is in the release |
| Constraint at this position | ||
| Conservation | phyloP 10 | GERP 2.2, phastCons 1 |
| Regional constraint | o/e 1.07 | unconstrained · MANE · 78 kb · p 0.12 · regional, not allelic |
| Overall | ||
| CADD | 29.6 | PHRED · no single calibrated threshold — expert panels disagree |
AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.
Population frequency
Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.
Variant & gene context
- Gene
- PAH
- Protein
- p.Pro275Ser
- Coding
- c.823C>T
- MANE Select
- NM_000277
- dbSNP
- rs62508691
- Type
- single nucleotide variant
- Location
- chr12:102852834 (GRCh38)
- Gene constraint
- LOEUF 1.265 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
- Structure
- AlphaFold pLDDT 89.04 · 21 PDB
- Residue 275
- a UniProt-annotated variant site (in pah deficiency; severe; reduced activity; increased affinity for the substrate; mildly reduced substrate activation; decreased cofactor affinity)
Disease context
phenylketonuria — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatmentsFor Phenylketonuria (Orphanet):
- Inheritance
- Autosomal recessive
- Onset
- Infancy
- Prevalence
- 1-9 / 100 000 (France)
Similar variants
- PAH p.Pro275Arg Likely pathogenic ★★★ same residue
- PAH p.Pro275Leu Pathogenic ★★★ same residue
- PAH p.Pro275= Likely benign ★ same residue
- PAH c.1065+1G>A Likely pathogenic ★★★ same condition
- PAH c.1065+1G>T Likely pathogenic ★★★ same condition
- PAH c.1065+3A>G Likely pathogenic ★★★ same condition
- PAH c.1066-11G>A Pathogenic ★★★ same condition
- PAH c.1066-14C>G Likely 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/pah-p-pro275ser (accessed [today's date]).
Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown