Is QDPR p.Ala87= (c.261T>C) pathogenic?

QDPR p.Ala87= (c.261T>C) is classified Likely benign in QDPR (ClinVar, Single submitter, 1 submitter; last evaluated 2023-03-24). Very rare (popmax 0.0022%, sas); Associated with dihydropteridine reductase deficiency.

What condition is associated with QDPR p.Ala87= (c.261T>C)?

QDPR p.Ala87= (c.261T>C) is associated with dihydropteridine reductase deficiency (ClinVar).

How common is QDPR p.Ala87= (c.261T>C) in the general population?

QDPR p.Ala87= (c.261T>C) is very rare (popmax 0.0022%, sas) (gnomAD).

QDPR p.Ala87=

Q: How is Hyperphenylalaninemia due to tetrahydrobiopterin deficiency inherited?

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

c.261T>C · rs2474675117 · VCV2991809

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.0022%, sas)

Conditions

dihydropteridine reductase deficiency

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
REVEL	0.04	moderately benign-leaning
Splicing
SpliceAI	<0.2	all four deltas below 0.2 · A>C here scores Δ0.21 · evaluated, not missing
Constraint at this position
Conservation	phyloP -0.052	GERP -4.6, phastCons 0.013
Overall
CADD	7.84	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0022% South Asian · 2/91,088 alleles

Filtering AF 0.000365% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000136%

Overall 0.000137% 2/1,461,892 alleles · very rare

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: QDPR
Protein: p.Ala87=
Coding: c.261T>C
MANE Select: NM_000320
dbSNP: rs2474675117
Type: single nucleotide variant
Location: chr4:17504413 (GRCh38)
Gene constraint: LOEUF 0.984 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 96.43 · 2 PDB

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

Disease context

dihydropteridine reductase deficiency — 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

QDPR c.436+2552A>G Pathogenic ★★ same condition
QDPR c.545+1G>A Pathogenic ★★ same condition
QDPR c.546-1G>A Likely pathogenic ★★ same condition
QDPR p.Arg221Ter Pathogenic ★★ same condition
QDPR p.His158Tyr Pathogenic/Likely pathogenic ★★ same condition
QDPR p.Phe212Ser Likely pathogenic ★★ same condition
QDPR p.Ser115Leu Pathogenic/Likely pathogenic ★★ same condition
QDPR p.Tyr150Cys 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/qdpr-p-ala87 (accessed [today's date]).

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