Genetic Variant BTD:p.Asn182Ser (chr3-15644461-A-G) – ACMG Classification: Uncertain_significance (3 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 7P and 4B. PM1PM2PM5PP2BP4_Strong

The NM_001370658.1(BTD):c.545A>G(p.Asn182Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000681 in 1,614,090 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign 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. N182I) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000068 ( 0 hom. )

Consequence

BTD
NM_001370658.1 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: -0.912

Publications

3 publications found

Variant links:

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

BTD links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM1

In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 uncertain in NM_001370658.1

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr3-15644461-A-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 2070102.

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.

BP4

Computational evidence support a benign effect (MetaRNN=0.026498824).

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

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
BTD	NM_001370658.1	MANE Select	c.545A>G	p.Asn182Ser	missense	Exon 4 of 4	NP_001357587.1
BTD	NM_001281723.4		c.545A>G	p.Asn182Ser	missense	Exon 4 of 4	NP_001268652.2
BTD	NM_001281724.3		c.545A>G	p.Asn182Ser	missense	Exon 6 of 6	NP_001268653.2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
BTD	ENST00000643237.3	MANE Select	c.545A>G	p.Asn182Ser	missense	Exon 4 of 4	ENSP00000495254.2
BTD	ENST00000303498.10	TSL:1	c.545A>G	p.Asn182Ser	missense	Exon 5 of 5	ENSP00000306477.6
BTD	ENST00000427382.2	TSL:4	c.545A>G	p.Asn182Ser	missense	Exon 4 of 4	ENSP00000397113.2

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152196

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000192

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

GnomAD2 exomes

AF:

0.0000398

AC:

AN:

251468

AF XY:

0.0000515

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000116

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000272

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.00000684

AC:

AN:

1461894

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

727248

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000671

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.000101

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112012

Other (OTH)

AF:

0.0000166

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.460

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152196

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74360

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41446

American (AMR)

AF:

0.00

AC:

AN:

15282

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.000192

AC:

AN:

5206

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.625

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000151

ExAC

AF:

0.0000412

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Biotinidase deficiency

Uncertain:3

Aug 27, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces asparagine with serine at codon 202 of the BTD protein (p.Asn202Ser). The asparagine residue is weakly conserved and there is a small physicochemical difference between asparagine and serine. This variant is present in population databases (rs397514376, ExAC 0.03%). This variant has not been reported in the literature in individuals affected with BTD-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The serine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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.

Oct 28, 2019

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

May 02, 2022

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.051

BayesDel_addAF

Benign

-0.45

BayesDel_noAF

Benign

-0.59

CADD

Benign

0.026

(source)

DANN

Benign

0.20

DEOGEN2

Benign

0.19

Eigen

Benign

-1.6

Eigen_PC

Benign

-1.6

FATHMM_MKL

Benign

0.034

LIST_S2

Benign

0.71

M_CAP

Benign

0.022

MetaRNN

Benign

0.026

MetaSVM

Benign

-0.85

MutationAssessor

Benign

-1.4

PhyloP100

-0.91

PrimateAI

Benign

0.26

PROVEAN

Benign

1.1

REVEL

Benign

0.14

Sift

Benign

1.0

Sift4G

Benign

1.0

Polyphen

0.0

Vest4

0.042

MutPred

0.42

Gain of catalytic residue at N202 (P = 0.0799)

MVP

0.47

MPC

0.058

ClinPred

0.012

GERP RS

-3.8

Varity_R

0.021

gMVP

0.53

Mutation Taster

=87/13

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over