Is BTD p.Leu342Ter (c.1025T>A) pathogenic?

BTD p.Leu342Ter (c.1025T>A) is classified Pathogenic in BTD (ClinVar, Single submitter, 2 submitters; last evaluated 2019-12-11). Ultra-rare (popmax 0.0165%, mid); Associated with biotinidase deficiency.

What condition is associated with BTD p.Leu342Ter (c.1025T>A)?

BTD p.Leu342Ter (c.1025T>A) is associated with biotinidase deficiency (ClinVar).

How common is BTD p.Leu342Ter (c.1025T>A) in the general population?

BTD p.Leu342Ter (c.1025T>A) is ultra-rare (popmax 0.0165%, mid) (gnomAD).

How is Biotinidase deficiency inherited?

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

BTD p.Leu342Ter

c.1025T>A · rs747548016 · VCV550894

Pathogenic Single submitter

Classification

Pathogenic

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 2 submitters

Consequence

nonsense (stop-gain)

predicted LoF

gnomAD v4.1

Rare

ultra-rare (popmax 0.0165%, mid)

Conditions

biotinidase 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	escapes	premature termination codon in the last exon (4 of 4) — the truncated protein is likely expressed. PVS1 input, not an applied code
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 2.7	GERP 2, phastCons 0.19
Overall
CADD	36.0	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 0.0165% Middle Eastern · 1/6,062 alleles

Overall 0.000137% 2/1,461,884 alleles · ultra-rare

Ancestry group	Frequency	1 in
Middle Easterngrpmax	0.0165%	6,062
European (non-Finnish)	8.47e-05%	1,180,020

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: BTD
Protein: p.Leu342Ter
Coding: c.1025T>A
MANE Select: NM_001370658
dbSNP: rs747548016
Type: single nucleotide variant
Location: chr3:15644941 (GRCh38)
Gene constraint: LOEUF 1.22 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 86.77

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

Disease context

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

For Biotinidase deficiency (Orphanet):

Inheritance: Autosomal recessive
Onset: Adolescent, Adult, Childhood, Infancy, Neonatal
Prevalence: 1-9 / 100 000 (Worldwide)

Similar variants

BTD p.Leu342= Likely benign ★ same residue
BTD c.1330G>C Pathogenic ★★ same condition
BTD c.249+1G>T Likely pathogenic ★★ same condition
BTD c.400-2A>G Likely pathogenic ★★ same condition
BTD c.-17+2T>C Pathogenic/Likely pathogenic ★★ same condition
BTD p.Ala142Val Pathogenic/Likely pathogenic ★★ same condition
BTD p.Ala217Thr Pathogenic/Likely pathogenic ★★ ⚠ same condition
BTD p.Ala269Val 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/btd-p-leu342ter (accessed [today's date]).

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