Is DRC4 p.Val18= (c.54C>T) pathogenic?

DRC4 p.Val18= (c.54C>T) is classified Likely benign in DRC4 (ClinVar, Single submitter, 2 submitters; last evaluated 2026-01-25). Ultra-rare (popmax 0.03%, amr); Associated with primary ciliary dyskinesia 33.

What condition is associated with DRC4 p.Val18= (c.54C>T)?

DRC4 p.Val18= (c.54C>T) is associated with primary ciliary dyskinesia 33 (ClinVar).

How common is DRC4 p.Val18= (c.54C>T) in the general population?

DRC4 p.Val18= (c.54C>T) is ultra-rare (popmax 0.03%, amr) (gnomAD).

How is Primary ciliary dyskinesia inherited?

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

DRC4 p.Val18=

c.54C>T · rs185349515 · VCV1556086

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.03%, amr)

Conditions

primary ciliary dyskinesia 33

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 -5.6	GERP -4.1
Overall
CADD	0.061	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.03% Admixed American · 18/60,028 alleles

Filtering AF 0.0194% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.016%

Overall 0.00229% 37/1,614,178 alleles · ultra-rare

Ancestry group	Frequency	1 in
Admixed Americangrpmax	0.03%	3,335
Middle Eastern	0.0165%	6,062
African / African-American	0.00533%	18,767
Remaining individualsnot grpmax-eligible	0.0048%	20,834
East Asian	0.00223%	44,880
European (non-Finnish)	0.000847%	118,003

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: DRC4
Protein: p.Val18=
Coding: c.54C>T
MANE Select: NM_001481
dbSNP: rs185349515
Type: single nucleotide variant
Location: chr16:90027686 (GRCh38)
Structure: AlphaFold pLDDT 85.12 · 1 PDB
Residue 18: the 'regulates microtubule-binding' region; the 'disordered' region

Full DRC4 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

primary ciliary dyskinesia 33 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Primary ciliary dyskinesia (Orphanet):

Inheritance: Autosomal dominant, Autosomal recessive, X-linked recessive
Onset: Neonatal
Prevalence: 1-5 / 10 000 (Pakistan)

Similar variants

DRC4 c.495+1G>T Likely pathogenic ★★ same condition
DRC4 p.Gln357Ter Pathogenic ★★ same condition
DRC4 p.Ala280Thr Uncertain significance ★★ ⚠ same condition
DRC4 p.Ala460Pro Uncertain significance ★★ ⚠ same condition
DRC4 p.Arg143Trp Uncertain significance ★★ ⚠ same condition
DRC4 p.Arg164Trp Uncertain significance ★★ ⚠ same condition
DRC4 p.Arg203Gln Uncertain significance ★★ ⚠ same condition
DRC4 p.Arg278Cys Uncertain significance ★★ ⚠ 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/drc4-p-val18 (accessed [today's date]).

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