3-15645093-G-C

Variant names:

• chr3-15645093-G-C
• rs374141881
• NM_001370658.1:c.1177G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_001370658.1(BTD):​c.1177G>C​(p.Gly393Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,192 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G393S) has been classified as Uncertain significance.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: BTD NM_001370658.1 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.92
• 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: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 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, 0.985

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.1177G>C	p.Gly393Arg	missense	Exon 4 of 4	NP_001357587.1
	BTD	NM_001281723.4		c.1177G>C	p.Gly393Arg	missense	Exon 4 of 4	NP_001268652.2
	BTD	NM_001281724.3		c.1177G>C	p.Gly393Arg	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.1177G>C	p.Gly393Arg	missense	Exon 4 of 4	ENSP00000495254.2
	BTD	ENST00000303498.10	TSL:1	c.1177G>C	p.Gly393Arg	missense	Exon 5 of 5	ENSP00000306477.6
	BTD	ENST00000427382.2	TSL:4	c.1177G>C	p.Gly393Arg	missense	Exon 4 of 4	ENSP00000397113.2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152192 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152192 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74370

African (AFR) AF: 0.0000241 AC: 1 AN: 41444

American (AMR) AF: 0.00 AC: 0 AN: 15274

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10618

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68038

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Biotinidase deficiency Uncertain:1

Mar 10, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 413 of the BTD protein (p.Gly413Arg). This variant is present in population databases (no rsID available, gnomAD 0.01%). This missense change has been observed in individual(s) with biochemical features of biotinidase deficiency (Invitae). ClinVar contains an entry for this variant (Variation ID: 2113926). 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. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.54
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.91	D
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D
M_CAP	Uncertain	0.24	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Pathogenic	3.4	M
PhyloP100		9.9
PrimateAI	Benign	0.47	T
PROVEAN	Pathogenic	-7.1	D
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.95
MutPred		0.93		Gain of ubiquitination at K411 (P = 0.0743)
MVP		0.99
MPC		0.46
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.80
gMVP		0.91
Mutation Taster		=5/95	disease causing

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: rs374141881; hg19: chr3-15686600;