Submissions for variant NM_001370658.1(BTD):c.992del (p.Thr331fs)

dbSNP: rs397514398

Total submissions: 5

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
GeneDx	RCV000269677	SCV000329855	pathogenic	not provided	2018-09-27	criteria provided, single submitter	clinical testing	The c.1052delC variant in the BTD gene has been reported previously in association with biotinidase deficiency (Wolf et al. 2002; Iqbal et al. 2010; Gannavarapu et al. 2015). The c.1052delC variant has been reported to be associated with profound biotinidase deficiency in a patient who also harbored a second frameshift variant as well as in a patient homozygous for c.1052delC (Wolf et al. 2002; Iqbal et al. 2010). However, a second patient homozygous for c.1052delC was reported with partial biotinidase deficiency (Iqbal et al. 2010). The c.1052delC deletion causes a frameshift starting with codon Threonine 351, changes this amino acid to a Lysine residue and creates a premature Stop codon at position 12 of the new reading frame, denoted p.Thr351LysfsX12. This pathogenic variant is predicted to cause loss of normal protein function through protein truncation. The c.1052delC variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. In summary, we interpret c.1052delC to be a pathogenic variant.
Quest Diagnostics Nichols Institute San Juan Capistrano	RCV000269677	SCV000600935	pathogenic	not provided	2020-11-13	criteria provided, single submitter	clinical testing	The variant results in a shift of the reading frame, and is therefore predicted to result in the loss of a functional protein. Found in at least one symptomatic patient, and not found in general population data.
Labcorp Genetics (formerly Invitae), Labcorp	RCV000021980	SCV001235508	pathogenic	Biotinidase deficiency	2023-10-28	criteria provided, single submitter	clinical testing	This sequence change creates a premature translational stop signal (p.Thr351Lysfs*12) in the BTD gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 193 amino acid(s) of the BTD protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with profound biotinidase deficiency (PMID: 12359137, 15776412, 20083419). ClinVar contains an entry for this variant (Variation ID: 25057). This variant disrupts a region of the BTD protein in which other variant(s) (p.Leu498Phefs*13) have been determined to be pathogenic (PMID: 17382128, 19728141, 29359854). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic.
Baylor Genetics	RCV000021980	SCV004211459	pathogenic	Biotinidase deficiency	2023-05-23	criteria provided, single submitter	clinical testing
Counsyl	RCV000021980	SCV000486792	pathogenic	Biotinidase deficiency	2016-08-09	no assertion criteria provided	clinical testing