Is PRF1 p.Val19Ile (c.55G>A) pathogenic?

PRF1 p.Val19Ile (c.55G>A) is classified Uncertain significance in PRF1 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2022-07-06). AlphaMissense: likely benign (0.0935); Very rare (popmax 0.00447%, eas); Associated with familial hemophagocytic lymphohistiocytosis 2.

What condition is associated with PRF1 p.Val19Ile (c.55G>A)?

PRF1 p.Val19Ile (c.55G>A) is associated with familial hemophagocytic lymphohistiocytosis 2 (ClinVar).

How common is PRF1 p.Val19Ile (c.55G>A) in the general population?

PRF1 p.Val19Ile (c.55G>A) is very rare (popmax 0.00447%, eas) (gnomAD).

How is Familial hemophagocytic lymphohistiocytosis inherited?

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

What do computational predictors say about PRF1 p.Val19Ile (c.55G>A)?

AlphaMissense predicts likely benign (score 0.0935) — an in-silico prediction, not a clinical call.

PRF1 p.Val19Ile

c.55G>A · rs772896823 · VCV300336

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

AlphaMissense

likely benign

0.0935 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00447%, eas)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

familial hemophagocytic lymphohistiocytosis 2

Computational evidence

Protein change
AlphaMissense	0.0935	likely benign
REVEL	0.135	moderately benign-leaning
SaProt	LLR -8.38	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -2.7	GERP -1.8
Regional constraint	o/e 0.97	unconstrained · MANE · 2,846 bp · p 0.42 · regional, not allelic
Overall
CADD	0.048	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean tolerated — a triage signal, not a reclassification

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00447% East Asian · 2/44,742 alleles

Filtering AF 0.00216% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00191%

Overall 0.00242% 39/1,610,224 alleles · very rare exomes 37/1,457,946 · genomes 2/152,278 · joint denominator

Ancestry group	Frequency	1 in
East Asiangrpmax	0.00447%	22,371
Ashkenazi Jewishnot grpmax-eligible	0.0034%	29,450
European (non-Finnish)	0.00297%	33,677
Admixed American	0.00169%	59,342

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: PRF1
Protein: p.Val19Ile
Coding: c.55G>A
MANE Select: NM_001083116
dbSNP: rs772896823
Type: single nucleotide variant
Location: chr10:70600848 (GRCh38)
Gene constraint: LOEUF 1.438 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 91.01

Full PRF1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

familial hemophagocytic lymphohistiocytosis 2 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Familial hemophagocytic lymphohistiocytosis (Orphanet):

Inheritance: Autosomal recessive
Onset: Adolescent, Infancy
Prevalence: 1-9 / 100 000 (Sweden)

Similar variants

PRF1 c.539+2T>A Pathogenic/Likely pathogenic ★★ same condition
PRF1 p.Arg225Trp Pathogenic ★★ ⚠ same condition
PRF1 p.Arg232Cys Pathogenic/Likely pathogenic ★★ ⚠ same condition
PRF1 p.Arg299Cys Pathogenic/Likely pathogenic ★★ same condition
PRF1 p.Arg356Trp Pathogenic/Likely pathogenic ★★ ⚠ same condition
PRF1 p.Arg361Trp Pathogenic/Likely pathogenic ★★ ⚠ same condition
PRF1 p.Arg390Ter Pathogenic ★★ same condition
PRF1 p.Arg410Pro Pathogenic/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/prf1-p-val19ile (accessed [today's date]).

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