Is CPT2 p.Ser26fs (c.75del) pathogenic?

CPT2 p.Ser26fs (c.75del) is classified Pathogenic/Likely pathogenic in CPT2 (ClinVar, Multiple submitters, 6 submitters; last evaluated 2026-01-18). Very rare (popmax 0.00414%, afr); Associated with carnitine palmitoyltransferase II deficiency.

How common is CPT2 p.Ser26fs (c.75del) in the general population?

CPT2 p.Ser26fs (c.75del) is very rare (popmax 0.00414%, afr) (gnomAD).

How is Carnitine palmitoyltransferase II deficiency inherited?

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

CPT2 p.Ser26fs

Q: What condition is associated with CPT2 p.Ser26fs (c.75del)?

CPT2 p.Ser26fs (c.75del) is associated with carnitine palmitoyltransferase II deficiency, carnitine palmitoyl transferase II deficiency, myopathic form, carnitine palmitoyl transferase II deficiency, severe infantile form (ClinVar).

c.75del · rs1057517493 · VCV371730

Pathogenic/Likely pathogenic Multiple submitters

Classification

Pathogenic/Likely pathogenic

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 6 submitters

Consequence

frameshift

predicted LoF

gnomAD v4.1

Rare

very rare (popmax 0.00414%, afr)

Conditions

carnitine palmitoyltransferase II deficiency

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Consequence	frameshift	predicted loss-of-function
NMD	predicted	premature termination codon in exon 1 of 5
Splicing
SpliceAI	—	not assessed · substitutions only
Constraint at this position
Conservation	phyloP 2.7	GERP 1.9, phastCons 0.18
Overall
CADD	10.97	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 0.00414% African / African-American · 3/72,408 alleles

Filtering AF 0.0011% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000505%

Overall 0.000195% 3/1,535,208 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: CPT2
Protein: p.Ser26fs
Coding: c.75del
MANE Select: NM_000098
dbSNP: rs1057517493
Type: Deletion
Location: chr1:53197018 (GRCh38)
Gene constraint: LOEUF 1.038 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 94.52

Full CPT2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

carnitine palmitoyltransferase II deficiency — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: carnitine palmitoyl transferase II deficiency, myopathic form carnitine palmitoyl transferase II deficiency, severe infantile form carnitine palmitoyl transferase II deficiency, neonatal form encephalopathy, acute, infection-induced, susceptibility to, 4

For Carnitine palmitoyltransferase II deficiency (Orphanet):

Inheritance: Autosomal recessive
Onset: All ages

Similar variants

CPT2 p.Ser26Gly Uncertain significance ⚠ same residue
CPT2 p.Ala643_Leu644insTer Pathogenic/Likely pathogenic ★★ same condition
CPT2 p.Arg382fs Pathogenic/Likely pathogenic ★★ same condition
CPT2 p.Asp576fs Pathogenic/Likely pathogenic ★★ same condition
CPT2 p.Gln33fs Pathogenic ★★ same condition
CPT2 p.Glu285fs Pathogenic/Likely pathogenic ★★ same condition
CPT2 p.Leu178_Pro180delinsPhe Pathogenic ★★ same condition
CPT2 p.Leu556fs 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/cpt2-p-ser26fs (accessed [today's date]).

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