rs397514425

Positions:

• chr3-15645346-C-CT

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001370658.1(BTD):​c.1433dup​(p.Leu478PhefsTer13) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BTD NM_001370658.1 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: -0.752

Genes affected

BTD (HGNC:1122): (biotinidase) The protein encoded by this gene functions to recycle protein-bound biotin by cleaving biocytin (biotin-epsilon-lysine), a normal product of carboxylase degradation, resulting in regeneration of free biotin. The encoded protein has also been shown to have biotinyl transferase activity. Mutations in this gene are associated with biotinidase deficiency. Multiple transcript variants encoding different isoforms have been described. [provided by RefSeq, Aug 2013]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 32 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-15645346-C-CT is Pathogenic according to our data. Variant chr3-15645346-C-CT is described in ClinVar as [Pathogenic]. Clinvar id is 587752.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BTD	NM_001370658.1	c.1433dup	p.Leu478PhefsTer13	frameshift_variant	4/4	ENST00000643237.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BTD	ENST00000643237.3	c.1433dup	p.Leu478PhefsTer13	frameshift_variant	4/4		NM_001370658.1	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251394 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135870

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461892 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727246

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Biotinidase deficiency Pathogenic:3

Pathogenic, no assertion criteria provided	clinical testing	Center for Molecular Medicine, Children’s Hospital of Fudan University	Mar 08, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Dec 23, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Feb 04, 2022	For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this premature translational stop signal affects BTD function (PMID: 29359854). Algorithms developed to predict the effect of variants on protein structure and function are not available or were not evaluated for this variant. ClinVar contains an entry for this variant (Variation ID: 587752). This premature translational stop signal has been observed in individual(s) with biotinidase deficiency (PMID: 17382128, 19728141, 29359854). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is present in population databases (rs760773815, gnomAD 0.006%). This sequence change creates a premature translational stop signal (p.Leu498Phefs*13) in the BTD gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 46 amino acid(s) of the BTD protein. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs397514425; hg19: chr3-15686853;