Is CA5A p.Arg32Ter (c.94C>T) pathogenic?

CA5A p.Arg32Ter (c.94C>T) is classified Pathogenic in CA5A (ClinVar, Multiple submitters, 2 submitters; last evaluated 2025-10-26). Very rare (popmax 0.00267%, afr); Associated with hyperammonemic encephalopathy due to carbonic anhydrase VA deficiency.

What condition is associated with CA5A p.Arg32Ter (c.94C>T)?

CA5A p.Arg32Ter (c.94C>T) is associated with hyperammonemic encephalopathy due to carbonic anhydrase VA deficiency (ClinVar).

How common is CA5A p.Arg32Ter (c.94C>T) in the general population?

CA5A p.Arg32Ter (c.94C>T) is very rare (popmax 0.00267%, afr) (gnomAD).

CA5A p.Arg32Ter

Q: How is Hyperammonemic encephalopathy due to carbonic anhydrase VA deficiency inherited?

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

c.94C>T · rs767402215 · VCV570252

Pathogenic Multiple submitters

Classification

Pathogenic

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

Consequence

nonsense (stop-gain)

predicted LoF

gnomAD v4.1

Rare

very rare (popmax 0.00267%, afr)

Conditions

hyperammonemic encephalopathy due to carbonic anhydrase VA deficiency

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Consequence	nonsense (stop-gain)	predicted loss-of-function
NMD	predicted	premature termination codon in exon 1 of 7
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 0.25	GERP -1.6
Overall
CADD	35.0	PHRED · no single calibrated threshold — expert panels disagree

Predicted loss-of-function is descriptive, not an applied PVS1 code.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00267% African / African-American · 2/74,858 alleles

Filtering AF 0.00138% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00116%

Overall 0.00174% 28/1,613,796 alleles · very rare exomes 26/1,461,758 · genomes 2/152,038 · joint denominator

Ancestry group	Frequency	1 in
Remaining individualsnot grpmax-eligible	0.0032%	31,243
African / African-Americangrpmax	0.00267%	37,429
European (non-Finnish)	0.00203%	49,163

Remaining individuals shows a higher raw frequency than the grpmax group above it. gnomAD excludes bottlenecked groups — Finnish, Ashkenazi Jewish, Amish and “Remaining individuals” — from grpmax, because founder effects make their frequencies unrepresentative for filtering. The table is sorted by frequency, so an excluded group can sit above the grpmax row.

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: CA5A
Protein: p.Arg32Ter
Coding: c.94C>T
MANE Select: NM_001739
dbSNP: rs767402215
Type: single nucleotide variant
Location: chr16:87936357 (GRCh38)
Gene constraint: LOEUF 1.257 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 84.38

Full CA5A gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

hyperammonemic encephalopathy due to carbonic anhydrase VA deficiency — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Hyperammonemic encephalopathy due to carbonic anhydrase VA deficiency (Orphanet):

Inheritance: Autosomal recessive
Onset: Childhood, Infancy, Neonatal

Similar variants

CA5A p.Glu241Lys Pathogenic/Likely pathogenic ★★ same condition
CA5A p.Ala149Thr Uncertain significance ★★ ⚠ same condition
CA5A p.Ala208Val Uncertain significance ★★ ⚠ same condition
CA5A p.Ala261Val Uncertain significance ★★ ⚠ same condition
CA5A p.Arg26His Uncertain significance ★★ ⚠ same condition
CA5A p.Asp216Ala Uncertain significance ★★ ⚠ same condition
CA5A p.Gln79Glu Uncertain significance ★★ ⚠ same condition
CA5A p.His143Asp 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/ca5a-p-arg32ter (accessed [today's date]).

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