rs397514371

chr3-15644440-A-G

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_001370658.1(BTD):c.524A>G(p.Asn175Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,894 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. N175D) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: BTD NM_001370658.1 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.31

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 12 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, 3 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 chr3-15644439-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 25021.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Likely_pathogenic=1, Pathogenic=1}.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988
• PP5: Variant 3-15644440-A-G is Pathogenic according to our data. Variant chr3-15644440-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2203315.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr3-15644440-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BTD	NM_001370658.1	c.524A>G	p.Asn175Ser	missense_variant	4/4	ENST00000643237.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BTD	ENST00000643237.3	c.524A>G	p.Asn175Ser	missense_variant	4/4		NM_001370658.1	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251454 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135884

Gnomad AFR exome AF: 0.00

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: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461894 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727248

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

Alfa AF: 0.00455 Hom.: 0

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Biotinidase deficiency Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Nov 29, 2022

This variant disrupts the p.Asn195 amino acid residue in BTD. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 9396567, 11865279). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. This missense change has been observed in individual(s) with biotinidase deficiency (PMID: 17185019). This variant is present in population databases (rs397514371, gnomAD 0.0009%). This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 195 of the BTD protein (p.Asn195Ser). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.36
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Uncertain	0.090
Cadd	Uncertain	26
Dann	Uncertain	1.0
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	1.0	D
M_CAP	Pathogenic	0.31	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.54	T
Polyphen		1.0	.;.;D;.;.;.;.;.
Vest4		0.97, 0.98, 0.98
MutPred		0.98		.;.;Gain of catalytic residue at N195 (P = 0.054);.;.;.;.;.;
MVP		0.99
MPC		0.38
ClinPred		0.99	D
GERP RS		5.8
Varity_R		0.81
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: rs397514371; hg19: chr3-15685947;