Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_153816.6(SNX14):c.2670delT(p.Cys890fs) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000403 in 1,612,764 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.
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 Pathogenic. Variant got 18 ACMG points.
PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 6-85508042-TA-T is Pathogenic according to our data. Variant chr6-85508042-TA-T is described in ClinVar as [Pathogenic]. Clinvar id is 190320.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
Not observed at significant frequency in large population cohorts (gnomAD); Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 25848753, 34426522) -
Mar 08, 2024
Clinical Genetics Laboratory, Skane University Hospital Lund
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
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Jul 01, 2020
CeGaT Center for Human Genetics Tuebingen
Significance: Pathogenic
Review Status: criteria provided, single submitter
Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: curation
The homozygous p.Lys889_Cys890insTer variant in SNX14 was identified by our study in one individual with spinocerebellar ataxia. The p.Lys889_Cys890insTer variant in SNX14 has been previously reported in 4 affected relatives from one family with autosomal recessive spinocerebellar ataxia 20 (PMID: 25848753) but has been identified in 0.01% (17/128632) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs774694340). Although this variant has been seen in the general population in a heterozygous state, its frequency is low enough to be consistent with a recessive carrier frequency. These 4 affected individuals were homozygotes (PMID: 25848753), and the individual identified by our study was also a homozygote, which increases the likelihood that the p.Lys889_Cys890insTer variant is pathogenic. This variant has also been reported in ClinVar (Variation ID: 190320) and has been interpreted as pathogenic by OMIM, GeneDx, HudsonAlpha Institute for Biotechnology, and CeGaT Center for Human Genetics Tuebingen. This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 889 and leads to a premature termination codon 1 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Loss of function of the SNX14 gene is an established disease mechanism in autosomal recessive spinocerebellar ataxia 20. In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive spinocerebellar ataxia 20. ACMG/AMP Criteria applied: PVS1, PM2_Supporting, PM3, PP1_Moderate (Richards 2015). -
May 01, 2015
OMIM
Significance: Pathogenic
Review Status: no assertion criteria provided
Collection Method: literature only
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Jan 12, 2017
HudsonAlpha Institute for Biotechnology, HudsonAlpha Institute for Biotechnology
Significance: Pathogenic
Review Status: criteria provided, single submitter