rs397514382

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1PM2PM5PP2PP3_ModeratePP5_Very_Strong

The NM_001370658.1(BTD):c.683T>C(p.Ile228Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,614,116 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I228L) has been classified as Likely pathogenic.

Frequency

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

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

BTD
NM_001370658.1 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6U:1

Conservation

PhyloP100: 8.02

Publications

2 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: Pathogenic. The variant received 17 ACMG points.

PM1

In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 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 chr3-15644598-A-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1004892.Status of the report is criteria_provided_single_submitter, 1 stars.

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, 0.931

PP5

Variant 3-15644599-T-C is Pathogenic according to our data. Variant chr3-15644599-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 25037.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BTD	NM_001370658.1 link	c.683T>C	p.Ile228Thr	missense_variant	Exon 4 of 4	ENST00000643237.3	NP_001357587.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BTD	ENST00000643237.3 link	c.683T>C	p.Ile228Thr	missense_variant	Exon 4 of 4		NM_001370658.1	ENSP00000495254.2		P43251-4

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152224

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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

GnomAD2 exomes

AF:

0.0000199

AC:

AN:

251456

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.0000615

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:

0.00000879

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461892

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727246

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.0000671

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

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:

1112010

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.495

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:

152224

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74378

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41452

American (AMR)

AF:

0.0000654

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68038

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

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:

0.00000378

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Biotinidase deficiency

Pathogenic:5Uncertain:1

Nov 14, 2017

Counsyl

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Mar 06, 2024

Baylor Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jun 18, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: BTD c.683T>C (p.Ile228Thr), also reported as c.743T>C (p.Ile248Thr), results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function all suggest that this variant is likely to be disruptive. The variant allele was found at a frequency of 2e-05 in 251456 control chromosomes. c.683T>C has been observed simple heterozygous, in the presumed or confirmed compound heterozygous state, or with 2 additional heterozygous variants (phase unknown) in individual(s) affected with clinical or biochemical features of Biotinidase Deficiency (example, Cowan_2012, Procter_2016, Jezela-Stanek_2022, Sharma_2024). In at least 1 individual, this variant was likely trans with a pathogenic variant. At least one publication reports experimental evidence evaluating an impact on protein function in patient confirmatory biochemical testing. The most pronounced variant effect results in <10% of normal activity in patient sample(s) (Cowan_2012). The following publications have been ascertained in the context of this evaluation (PMID: 22698809, 26810761, 35627187, 36684547, 38299772). ClinVar contains an entry for this variant (Variation ID: 25037). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Aug 18, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 248 of the BTD protein (p.Ile248Thr). This variant is present in population databases (rs397514382, gnomAD 0.003%). This missense change has been observed in individual(s) with biotinidase deficiency (PMID: 22698809, 26810761). ClinVar contains an entry for this variant (Variation ID: 25037). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt BTD protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

May 23, 2019

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The BTD c.743T>C; p.Ile248Thr variant (rs397514382) is reported in the literature in at least one individual affected with biotinidase deficiency who carried a second, pathogenic variant in BTD (Cowan 2012). This variant is reported in ClinVar (Variation ID: 25037), and is only observed on five alleles in the Genome Aggregation Database, indicating it is not a common polymorphism. The isoleucine at codon 248 is highly conserved, and computational analyses (SIFT, PolyPhen-2) predict that this variant is deleterious. Based on available information, this variant is considered to be likely pathogenic. References: Cowan TM et al. Increased incidence of profound biotinidase deficiency among Hispanic newborns in California. Mol Genet Metab. 2012 Aug;106(4):485-7. -

May 06, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:1

Sep 02, 2024

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The BTD c.743T>C (p.Ile248Thr) variant has been reported in the published literature in individuals with biotinidase deficiency (PMIDs: 26810761 (2016), 22698809 (2012)), including a newborn who also carried the Amish founder variant c.1330G>C (p.Asp444His) (PMID: 35627187 (2022)). The variant has been shown to result in low levels of biotinidise enzyme activity, however further experimental evidence is needed (PMID: 26810761 (2016), 22698809 (2012)). The frequency of this variant in the general population, 0.00002 (5/251456 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is damaging. Based on the available information, this variant is classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.72

BayesDel_addAF

Pathogenic

0.42

BayesDel_noAF

Pathogenic

0.44

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.60

.;.;D;.;.;.;T;.

Eigen

Pathogenic

0.73

Eigen_PC

Uncertain

0.65

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.94

.;D;D;.;.;D;D;D

M_CAP

Uncertain

0.27

MetaRNN

Pathogenic

0.93

D;D;D;D;D;D;D;D

MetaSVM

Pathogenic

0.84

MutationAssessor

Pathogenic

3.7

.;.;H;.;.;.;.;.

PhyloP100

8.0

PrimateAI

Uncertain

0.68

PROVEAN

Pathogenic

-4.5

.;D;.;.;.;D;D;D

REVEL

Pathogenic

0.88

Sift

Uncertain

0.0010

.;D;.;.;.;D;D;D

Sift4G

Pathogenic

0.0010

.;D;.;.;.;D;D;D

Polyphen

1.0

.;.;D;.;.;.;.;.

Vest4

0.92, 0.93, 0.93

MutPred

0.75

.;.;Loss of stability (P = 0.0172);.;.;.;.;.;

MVP

1.0

MPC

0.46

ClinPred

1.0

GERP RS

5.7

Varity_R

0.70

gMVP

0.96

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over