rs1553653888

chr3-15644797-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PM5 PP3

The NM_001370658.1(BTD):c.881A>G(p.His294Arg) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. H294L) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BTD NM_001370658.1 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.79

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 Likely_pathogenic. Variant got 7 ACMG points.

• PM1: In a hotspot region, there are 4 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 chr3-15644797-A-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2865860.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.801

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BTD	NM_001370658.1	c.881A>G	p.His294Arg	missense_variant	4/4	ENST00000643237.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BTD	ENST00000643237.3	c.881A>G	p.His294Arg	missense_variant	4/4		NM_001370658.1	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Oct 22, 2021

Variant summary: BTD c.881A>G (p.His294Arg) results in a non-conservative amino acid change located in the Carbon-nitrogen hydrolase domain (IPR003010) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251394 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.881A>G has been reported in the literature as a single variant in an asymptomatic Greek newborn with partial BTD activity (Thodi_2016). This report does not provide unequivocal conclusions about association of the variant with Biotinidase Deficiency. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. A ClinVar submitter (evaluation after 2014) cites the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Biotinidase deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Counsyl

Dec 12, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.71
BayesDel_addAF	Uncertain	0.081	D
BayesDel_noAF	Benign	-0.12
Cadd	Benign	23
Dann	Uncertain	0.99
Eigen	Uncertain	0.43
Eigen_PC	Uncertain	0.51
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Uncertain	0.10	D
MetaRNN	Pathogenic	0.80	D;D;D;D;D;D;D
MetaSVM	Uncertain	0.32	D
MutationTaster	Benign	0.88	D;D;D;D
PrimateAI	Benign	0.45	T
Polyphen		0.83	.;.;P;.;.;.;.
Vest4		0.69, 0.78, 0.72
MutPred		0.67		.;.;Loss of disorder (P = 0.0924);.;.;.;.;
MVP		0.99
MPC		0.21
ClinPred		0.95	D
GERP RS		5.8
Varity_R		0.53
gMVP		0.92

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: rs1553653888; hg19: chr3-15686304;