Is BTD p.Ser28= (c.84C>T) pathogenic?

BTD p.Ser28= (c.84C>T) is classified Likely benign in BTD (ClinVar, Single submitter, 1 submitter; last evaluated 2025-11-22). Ultra-rare (popmax 0.0164%, mid); Associated with biotinidase deficiency.

What condition is associated with BTD p.Ser28= (c.84C>T)?

BTD p.Ser28= (c.84C>T) is associated with biotinidase deficiency (ClinVar).

How common is BTD p.Ser28= (c.84C>T) in the general population?

BTD p.Ser28= (c.84C>T) is ultra-rare (popmax 0.0164%, mid) (gnomAD).

How is Biotinidase deficiency inherited?

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

BTD p.Ser28=

c.84C>T · rs144654790 · VCV2732704

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

ultra-rare (popmax 0.0164%, mid)

Conditions

biotinidase deficiency

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -1	GERP -1.9
Overall
CADD	3.432	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0164% Middle Eastern · 1/6,084 alleles

Filtering AF 0.00103% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00083%

Overall 0.00142% 23/1,614,052 alleles · ultra-rare

Ancestry group	Frequency	1 in
Middle Easterngrpmax	0.0164%	6,084
Remaining individualsnot grpmax-eligible	0.0032%	31,241
European (non-Finnish)	0.00161%	62,107
African / African-American	0.00133%	74,920

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.Ser28=
Coding: c.84C>T
MANE Select: NM_001370658
dbSNP: rs144654790
Type: single nucleotide variant
Location: chr3:15635523 (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 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
BTD p.Ala279Pro 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-ser28 (accessed [today's date]).

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