Is PTS p.Lys91= (c.273G>A) pathogenic?

PTS p.Lys91= (c.273G>A) is classified Likely benign in PTS (ClinVar, Single submitter, 1 submitter; last evaluated 2024-03-19). Very rare (popmax 0.0011%, sas); Associated with BH4-deficient hyperphenylalaninemia A.

What condition is associated with PTS p.Lys91= (c.273G>A)?

PTS p.Lys91= (c.273G>A) is associated with BH4-deficient hyperphenylalaninemia A (ClinVar).

How common is PTS p.Lys91= (c.273G>A) in the general population?

PTS p.Lys91= (c.273G>A) is very rare (popmax 0.0011%, sas) (gnomAD).

PTS p.Lys91=

Q: How is Hyperphenylalaninemia due to tetrahydrobiopterin deficiency inherited?

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

c.273G>A · rs1318726823 · VCV1671546

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.0011%, sas)

Conditions

BH4-deficient hyperphenylalaninemia A

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 8.5	GERP 2, phastCons 1
Overall
CADD	12.9	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0011% South Asian · 1/91,082 alleles

Filtering AF 0.000542% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000428%

Overall 0.000889% 13/1,461,800 alleles · very rare

Ancestry group	Frequency	1 in
South Asiangrpmax	0.0011%	91,082
European (non-Finnish)	0.00102%	98,330

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: PTS
Protein: p.Lys91=
Coding: c.273G>A
MANE Select: NM_000317
dbSNP: rs1318726823
Type: single nucleotide variant
Location: chr11:112233192 (GRCh38)
Gene constraint: LOEUF 1.695 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 96.01 · 1 PDB

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

Disease context

BH4-deficient hyperphenylalaninemia A — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Hyperphenylalaninemia due to tetrahydrobiopterin deficiency (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal
Prevalence: 1-9 / 1 000 000 (Japan)

Similar variants

PTS p.Lys91Arg Pathogenic/Likely pathogenic ★★ ⚠ same residue
PTS p.Lys91Glu Conflicting classifications of pathogenicity ★ ⚠ same residue
PTS c.186+1G>A Pathogenic ★★ same condition
PTS c.186+1G>T Pathogenic ★★ same condition
PTS c.187-2A>G Likely pathogenic ★★ same condition
PTS c.315-1G>A Pathogenic/Likely pathogenic ★★ same condition
PTS c.315-2A>G Pathogenic/Likely pathogenic ★★ same condition
PTS c.84-1G>A 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/pts-p-lys91 (accessed [today's date]).

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