Is QDPR p.Ser169= (c.507C>T) pathogenic?

QDPR p.Ser169= (c.507C>T) is classified Likely benign in QDPR (ClinVar, Multiple submitters, 2 submitters; last evaluated 2026-01-17). Ultra-rare (popmax 0.0198%, sas); Associated with dihydropteridine reductase deficiency.

What condition is associated with QDPR p.Ser169= (c.507C>T)?

QDPR p.Ser169= (c.507C>T) is associated with dihydropteridine reductase deficiency (ClinVar).

How common is QDPR p.Ser169= (c.507C>T) in the general population?

QDPR p.Ser169= (c.507C>T) is ultra-rare (popmax 0.0198%, sas) (gnomAD).

QDPR p.Ser169=

Q: How is Hyperphenylalaninemia due to tetrahydrobiopterin deficiency inherited?

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

c.507C>T · rs774932503 · VCV1546372

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0198%, sas)

Conditions

dihydropteridine reductase deficiency

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 -8.4	GERP -4.9
Overall
CADD	7.983	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0198% South Asian · 18/91,084 alleles

Filtering AF 0.0127% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0106%

Overall 0.00254% 41/1,613,986 alleles · ultra-rare

Ancestry group	Frequency	1 in
South Asiangrpmax	0.0198%	5,060
East Asian	0.00668%	14,961
African / African-American	0.00534%	18,732
Admixed American	0.00333%	30,003
Remaining individualsnot grpmax-eligible	0.0016%	62,478
European (non-Finnish)	0.0011%	90,771

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.Ser169=
Coding: c.507C>T
MANE Select: NM_000320
dbSNP: rs774932503
Type: single nucleotide variant
Location: chr4:17492270 (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-ser169 (accessed [today's date]).

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