Is AMPD2 p.Pro442= (c.1326T>C) pathogenic?

AMPD2 p.Pro442= (c.1326T>C) is classified Likely benign in AMPD2 (ClinVar, Multiple submitters, 3 submitters; last evaluated 2026-01-09). Ultra-rare (popmax 0.0408%, nfe); Associated with pontocerebellar hypoplasia type 9.

What condition is associated with AMPD2 p.Pro442= (c.1326T>C)?

AMPD2 p.Pro442= (c.1326T>C) is associated with pontocerebellar hypoplasia type 9, hereditary spastic paraplegia 63 (ClinVar).

How common is AMPD2 p.Pro442= (c.1326T>C) in the general population?

AMPD2 p.Pro442= (c.1326T>C) is ultra-rare (popmax 0.0408%, nfe) (gnomAD).

AMPD2 p.Pro442=

c.1326T>C · rs371970036 · VCV1210749

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0408%, nfe)

Conditions

pontocerebellar hypoplasia type 9

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
REVEL	0.033	moderately benign-leaning
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -5	GERP -3.9
Overall
CADD	2.441	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0408% European (non-Finnish) · 481/1,180,000 alleles

Filtering AF 0.0377% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0366%

Overall 0.0313% 505/1,613,814 alleles · ultra-rare exomes 470/1,461,714 · genomes 35/152,100 · joint denominator

Ancestry group	Frequency	1 in
European (non-Finnish)grpmax	0.0408%	2,453
Remaining individualsnot grpmax-eligible	0.016%	6,251
Finnishnot grpmax-eligible	0.0125%	7,980
African / African-American	0.00534%	18,739
Admixed American	0.00167%	60,022
South Asian	0.0011%	91,058

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: AMPD2
Protein: p.Pro442=
Coding: c.1326T>C
MANE Select: NM_001368809
dbSNP: rs371970036
Type: single nucleotide variant
Location: chr1:109628414 (GRCh38)
Gene constraint: LOEUF 0.705 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 81.28 · 5 PDB
Residue 442: an α-helix

Full AMPD2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

pontocerebellar hypoplasia type 9 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: hereditary spastic paraplegia 63

Similar variants

AMPD2 p.Pro442fs Likely pathogenic ★ same residue
AMPD2 c.1698+1G>A Pathogenic/Likely pathogenic ★★ same condition
AMPD2 p.Arg353Ter Pathogenic/Likely pathogenic ★★ same condition
AMPD2 p.Arg449Ter Pathogenic/Likely pathogenic ★★ same condition
AMPD2 p.Arg620His Pathogenic/Likely pathogenic ★★ same condition
AMPD2 p.Arg789His Likely pathogenic ★★ same condition
AMPD2 p.Glu174Ter Pathogenic/Likely pathogenic ★★ same condition
AMPD2 c.1080+3G>A 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/ampd2-p-pro442 (accessed [today's date]).

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