Is DBT p.Gln66Ter (c.196C>T) pathogenic?

DBT p.Gln66Ter (c.196C>T) is classified Likely pathogenic in DBT (ClinVar, Single submitter, 1 submitter; last evaluated 2020-01-17). Absent from gnomAD v4.1; Associated with maple syrup urine disease.

What condition is associated with DBT p.Gln66Ter (c.196C>T)?

DBT p.Gln66Ter (c.196C>T) is associated with maple syrup urine disease (ClinVar).

How common is DBT p.Gln66Ter (c.196C>T) in the general population?

DBT p.Gln66Ter (c.196C>T) is absent from gnomAD v4.1 (gnomAD).

How is Maple syrup urine disease inherited?

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

DBT p.Gln66Ter

c.196C>T · rs1663814011 · VCV983641

Likely pathogenic Single submitter

Classification

Likely pathogenic

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

Consequence

nonsense (stop-gain)

predicted LoF

gnomAD v4.1

Not reported

no allele count reported in gnomAD v4.1 (AN 1,591,034)

Conditions

maple syrup urine disease

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 3 of 11
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Pangolin	Δ0.20	loss · gain 0.01 · not in the SpliceAI release · independent
Constraint at this position
Conservation	phyloP 12	GERP 2.4, phastCons 1
Overall
CADD	40.0	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

No allele count reported in gnomAD v4.1 (AN 1,591,034). This is missing data, not an absence: the variant may or may not be present in gnomAD. Rarity (ACMG PM2) and BA1/BS1 cannot be assessed for it.

Variant & gene context

Gene: DBT
Protein: p.Gln66Ter
Coding: c.196C>T
MANE Select: NM_001918
dbSNP: rs1663814011
Type: single nucleotide variant
Location: chr1:100235491 (GRCh38)
Gene constraint: LOEUF 1.255 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 78.71 · 5 PDB
Residue 66: the lipoyl-binding domain; a β-strand

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

Disease context

maple syrup urine disease — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Maple syrup urine disease (Orphanet):

Inheritance: Autosomal recessive
Onset: Childhood, Infancy, Neonatal
Prevalence: 1-9 / 1 000 000 (Worldwide)

Similar variants

DBT p.Gln66= Conflicting classifications of pathogenicity ★ same residue
DBT c.1018-550A>G Pathogenic/Likely pathogenic ★★ same condition
DBT c.1281+1G>A Pathogenic/Likely pathogenic ★★ same condition
DBT c.1281+1G>T Pathogenic/Likely pathogenic ★★ same condition
DBT c.51+1G>T Pathogenic/Likely pathogenic ★★ same condition
DBT c.52-1G>A Pathogenic/Likely pathogenic ★★ same condition
DBT p.Arg291Ter Pathogenic ★★ same condition
DBT p.Arg301Cys 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/dbt-p-gln66ter (accessed [today's date]).

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