Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_ModeratePM2PP5_Moderate
The NM_001370658.1(BTD):c.250-1G>T variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000069 in 1,449,920 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).
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]
Verdict is Likely_pathogenic. Variant got 6 ACMG points.
PVS1
Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.094783716 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.4, offset of 9, new splice context is: ttcattttcatgatgtacAGatt. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 3-15641907-G-T is Pathogenic according to our data. Variant chr3-15641907-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 551671.Status of the report is criteria_provided_single_submitter, 1 stars.