Is PRF1 p.Ala122= (c.366T>A) pathogenic?

PRF1 p.Ala122= (c.366T>A) is classified Likely benign in PRF1 (ClinVar, Single submitter, 1 submitter; last evaluated 2023-08-09). Very rare (popmax 6.84e-05%); Associated with familial hemophagocytic lymphohistiocytosis 2.

What condition is associated with PRF1 p.Ala122= (c.366T>A)?

PRF1 p.Ala122= (c.366T>A) is associated with familial hemophagocytic lymphohistiocytosis 2 (ClinVar).

How common is PRF1 p.Ala122= (c.366T>A) in the general population?

PRF1 p.Ala122= (c.366T>A) is very rare (popmax 6.84e-05%) (gnomAD).

How is Familial hemophagocytic lymphohistiocytosis inherited?

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

PRF1 p.Ala122=

c.366T>A · rs1045149352 · VCV2707414

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 6.84e-05%)

Conditions

familial hemophagocytic lymphohistiocytosis 2

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 -1.2	GERP -4
Overall
CADD	0.324	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 6.84e-05%

Overall 6.84e-05% 1/1,461,818 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: PRF1
Protein: p.Ala122=
Coding: c.366T>A
MANE Select: NM_001083116
dbSNP: rs1045149352
Type: single nucleotide variant
Location: chr10:70600537 (GRCh38)
Gene constraint: LOEUF 1.438 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 91.01
Residue 122: the macpf domain

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-ala122 (accessed [today's date]).

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