Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_ModeratePM2PP5_Moderate
The NM_153816.6(SNX14):c.2746-2A>G variant causes a splice acceptor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000688 in 1,452,874 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 (★).
SNX14 (HGNC:14977): (sorting nexin 14) This gene encodes a member of the sorting nexin family. Members of this family have a phox (PX) phosphoinositide binding domain and are involved in intracellular trafficking. The encoded protein also contains a regulator of G protein signaling (RGS) domain. Regulator of G protein signaling family members are regulatory molecules that act as GTPase activating proteins for G alpha subunits of heterotrimeric G proteins. Alternate splicing results in transcript variants encoding distinct isoforms. [provided by RefSeq, Jul 2014]
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 0.01971137 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4, offset of 33, new splice context is: tattggacattgtgatacAGgaa. 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 6-85507291-T-C is Pathogenic according to our data. Variant chr6-85507291-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2573000.Status of the report is criteria_provided_single_submitter, 1 stars.
Likely pathogenic, criteria provided, single submitter
clinical testing
Illumina Laboratory Services, Illumina
May 08, 2023
The SNX14 c.2746-2A>G variant results in a substitution at the consensus splice acceptor site, which is predicated to result in splicing defects that lead to truncated protein. This variant has been reported in a homozygous state in two siblings with spinocerebellar ataxia 20 (doi:10.5734/jgm.2021.18.2.127). The c.2746-2A>G variant is not observed at a significant frequency in version 2.1.1 or version 3.1.2 of the Genome Aggregation Database. Based on the available evidence, the c.2746-2A>G variant is classified as likely pathogenic for spinocerebellar ataxia 20. -