rs138818907

Positions:

• chr3-15645345-C-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_001370658.1(BTD):​c.1429C>T​(p.Pro477Ser) variant causes a missense change. The variant allele was found at a frequency of 0.0000335 in 1,614,204 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: 𝑓 0.00012 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000025 (0 hom.)
• Consequence: BTD NM_001370658.1 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:13
• Conservation: PhyloP100: 4.77

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 16 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_001370658.1
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.981
• PP5: Variant 3-15645345-C-T is Pathogenic according to our data. Variant chr3-15645345-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 25094.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr3-15645345-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BTD	NM_001370658.1	c.1429C>T	p.Pro477Ser	missense_variant	4/4	ENST00000643237.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BTD	ENST00000643237.3	c.1429C>T	p.Pro477Ser	missense_variant	4/4		NM_001370658.1	P1

Frequencies

GnomAD3 genomes AF: 0.000112 AC: 17 AN: 152196 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000410

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

GnomAD3 exomes AF: 0.0000239 AC: 6 AN: 251394 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135868

Gnomad AFR exome AF: 0.000246

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000246 AC: 36 AN: 1461890 Hom.: 0 Cov.: 32 AF XY: 0.0000234 AC XY: 17 AN XY: 727244

Gnomad4 AFR exome AF: 0.000747

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000629

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.000118 AC: 18 AN: 152314 Hom.: 0 Cov.: 32 AF XY: 0.000121 AC XY: 9 AN XY: 74480

Gnomad4 AFR AF: 0.000433

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000288 Hom.: 0

Bravo AF: 0.0000982

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.0000247 AC: 3

Asia WGS AF: 0.000289 AC: 1 AN: 3478

EpiCase AF: 0.000109

EpiControl AF: 0.0000593

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:13

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Biotinidase deficiency Pathogenic:8

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 15, 2024	This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 497 of the BTD protein (p.Pro497Ser). This variant is present in population databases (rs138818907, gnomAD 0.04%). This missense change has been observed in individual(s) with with profound biotinidase deficiency and in combination with other variants in individuals with partial biotinidase deficiency (PMID: 10400129, 15776412, 19757147, 20224900, 25754625, 26361991, 26810761). ClinVar contains an entry for this variant (Variation ID: 25094). 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 with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 02, 2024	- -
Pathogenic, criteria provided, single submitter	research	Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center	Mar 17, 2024	- -
Likely pathogenic, no assertion criteria provided	clinical testing	Counsyl	Dec 21, 2017	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 10, 2022	Variant summary: BTD c.1429C>T (p.Pro477Ser) results in a non-conservative amino acid change in the Vanin, C-terminal domain (IPR043957) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 3.9e-05 in 282800 control chromosomes (gnomAD). This frequency is not higher than the estimated maximum expected for a pathogenic variant in BTD causing Biotinidase Deficiency (3.9e-05 vs 0.0046), allowing no conclusion about variant significance. c.1429C>T has been reported in the literature in multiple compound heterozygous (e.g. Norrgard_1999, Sarafoglou_2009, Kasapkara_2015) and homozygous (e.g. Sarafoglou_2009, Ercan_2021) individuals affected mostly with profound Biotinidase Deficiency. These data indicate that the variant is very likely to be associated with disease. Seven ClinVar submitters have assessed the variant since 2014: one classified the variant as likely pathogenic and six as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Dec 14, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Neuberg Centre For Genomic Medicine, NCGM	-	The missense c.1429C>T (p.Pro477Ser) variant in BTD gene has been reported previously in both homozygous and compound heterozygous state in multiple individuals affected with profound biotinidase deficiency (Sarafoglou et al. 2009; Kasapkara et al.2015; Procter et al. 2016). The p.Pro477Ser variant is reported with an allele frequency of 0.002% in the gnomAD exomes database and is novel (not in any individuals) in 1000 Genomes database. This variant has been reported to the ClinVar database as Likely Pathogenic / Pathogenic (multiple submissions). The amino acid change p.Pro477Ser in BTD is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. The amino acid Pro at position 477 is changed to a Ser changing protein sequence and it might alter its composition and physico-chemical properties. Additional studies will be required to prove the pathogenicity of this variant. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:5

Pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Nov 27, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 15, 2022	In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 25087612, 15776412, 26589311, 19757147, 25423671, 25754625, 20224900, 24516753, 29353266, 25967232, 28498829, 26361991, 26810761, 10400129) -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics	May 09, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Sep 10, 2012	- -
Pathogenic, criteria provided, single submitter	clinical testing	Al Jalila Children’s Genomics Center, Al Jalila Childrens Speciality Hospital	Dec 17, 2022	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.48
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.50
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	.;.;D;.;.;.;.
Eigen	Pathogenic	0.74
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.94	.;D;D;.;.;D;D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.2	.;.;M;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Benign	0.47	T
PROVEAN	Pathogenic	-7.8	.;D;.;.;.;D;D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	.;D;.;.;.;D;D
Sift4G	Pathogenic	0.0	.;D;.;.;.;D;D
Polyphen		1.0	.;.;D;.;.;.;.
Vest4		0.92, 0.94, 0.92
MVP		1.0
MPC		0.42
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.87
gMVP		0.96

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: rs138818907; hg19: chr3-15686852;