3-15644670-T-G

Variant names:

• chr3-15644670-T-G
• rs397514387
• NM_001370658.1:c.754T>G

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1 PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_001370658.1(BTD):​c.754T>G​(p.Trp252Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: BTD NM_001370658.1 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 8.02
• Publications: 1 publications found

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]

BTD Gene-Disease associations (from GenCC):

• biotinidase deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Myriad Women’s Health, ClinGen, Orphanet, Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
• Leigh syndrome

  Inheritance: AR Classification: MODERATE Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 17 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_001370658.1
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 88 curated pathogenic missense variants (we use a threshold of 10). The gene has 9 curated benign missense variants. Gene score misZ: -0.52516 (below the threshold of 3.09). Trascript score misZ: 0.15371 (below the threshold of 3.09). GenCC associations: The gene is linked to Leigh syndrome, biotinidase deficiency.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.986
• PP5: Variant 3-15644670-T-G is Pathogenic according to our data. Variant chr3-15644670-T-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 25043.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001370658.1. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BTD	NM_001370658.1	MANE Select	c.754T>G	p.Trp252Gly	missense	Exon 4 of 4	NP_001357587.1
	BTD	NM_001281723.4		c.754T>G	p.Trp252Gly	missense	Exon 4 of 4	NP_001268652.2
	BTD	NM_001281724.3		c.754T>G	p.Trp252Gly	missense	Exon 6 of 6	NP_001268653.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BTD	ENST00000643237.3	MANE Select	c.754T>G	p.Trp252Gly	missense	Exon 4 of 4	ENSP00000495254.2
	BTD	ENST00000303498.10	TSL:1	c.754T>G	p.Trp252Gly	missense	Exon 5 of 5	ENSP00000306477.6
	BTD	ENST00000427382.2	TSL:4	c.754T>G	p.Trp252Gly	missense	Exon 4 of 4	ENSP00000397113.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000795 AC: 2 AN: 251444 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000578

Gnomad ASJ exome AF: 0.00

Gnomad EAS 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: 0.00000137 AC: 2 AN: 1461892 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727248

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.0000447 AC: 2 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000151

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Biotinidase deficiency Pathogenic:3

Jul 31, 2023

3billion

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.001%). Predicted Consequence/Location: Missense variant In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.93; 3Cnet: 1.00). Same nucleotide change resulting in same amino acid change has been previously reported to be associated with BTD-related disorder (ClinVar ID: VCV000025043 /3billion dataset). The variant has been reported to be in trans with a pathogenic variant as either compound heterozygous or homozygous in at least one similarly affected unrelated individual (PMID: 22698809). Therefore, this variant is classified as Likely pathogenic according to the recommendation of ACMG/AMP guideline.

Jun 07, 2022

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

May 03, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt BTD protein function. ClinVar contains an entry for this variant (Variation ID: 25043). This missense change has been observed in individual(s) with biotinidase deficiency (PMID: 22698809; Invitae). 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 (rs397514387, gnomAD 0.006%). This sequence change replaces tryptophan, which is neutral and slightly polar, with glycine, which is neutral and non-polar, at codon 272 of the BTD protein (p.Trp272Gly).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	30
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.69	D
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Pathogenic	3.8	H
PhyloP100		8.0
PrimateAI	Uncertain	0.69	T
PROVEAN	Pathogenic	-12	D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0030	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.93
MutPred		0.88		Loss of stability (P = 0.0966)
MVP		0.98
MPC		0.55
ClinPred		1.0	D
GERP RS		5.8
Varity_R		0.98
gMVP		0.99
Mutation Taster		=2/98	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs397514387; hg19: chr3-15686177;