3-15644442-AC-A

Position:

• chr3-15644442-AC-A

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.527del​(p.Thr176LysfsTer68) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: BTD NM_001370658.1 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.89

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 203 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-15644442-AC-A is Pathogenic according to our data. Variant chr3-15644442-AC-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 528478.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.527del	p.Thr176LysfsTer68	frameshift_variant	4/4	ENST00000643237.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BTD	ENST00000643237.3	c.527del	p.Thr176LysfsTer68	frameshift_variant	4/4		NM_001370658.1	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Biotinidase deficiency Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Aug 21, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Nov 08, 2022	This sequence change creates a premature translational stop signal (p.Thr196Lysfs*68) in the BTD gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 348 amino acid(s) of the BTD protein. For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the BTD protein in which other variant(s) (p.Leu498Phefs*13) have been determined to be pathogenic (PMID: 17382128, 19728141, 29359854). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 528478). This premature translational stop signal has been observed in individual(s) with biotinidase deficiency (PMID: 22698809). This variant is not present in population databases (gnomAD no frequency). -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Apr 25, 2017	- -

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: rs1553653680; hg19: chr3-15685949;