chr1-100017814-A-G
Variant summary
Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2PP3PP5_Very_Strong
The NM_012243.3(SLC35A3):c.886A>G(p.Ser296Gly) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.0000264 in 1,550,916 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S296N) has been classified as Uncertain significance.
Frequency
Consequence
NM_012243.3 missense, splice_region
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 11 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
SLC35A3 | ENST00000533028.8 | c.886A>G | p.Ser296Gly | missense_variant, splice_region_variant | Exon 7 of 8 | 1 | NM_012243.3 | ENSP00000433849.1 | ||
ENSG00000283761 | ENST00000639037.1 | c.753+2394A>G | intron_variant | Intron 6 of 16 | 5 | ENSP00000492745.1 |
Frequencies
GnomAD3 genomes AF: 0.0000526 AC: 8AN: 152198Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000617 AC: 13AN: 210628Hom.: 0 AF XY: 0.0000607 AC XY: 7AN XY: 115352
GnomAD4 exome AF: 0.0000236 AC: 33AN: 1398718Hom.: 0 Cov.: 26 AF XY: 0.0000215 AC XY: 15AN XY: 696176
GnomAD4 genome AF: 0.0000526 AC: 8AN: 152198Hom.: 0 Cov.: 32 AF XY: 0.0000672 AC XY: 5AN XY: 74358
ClinVar
Submissions by phenotype
Autism spectrum disorder - epilepsy - arthrogryposis syndrome Pathogenic:5
Variant summary: c.1226A>G affects a conserved nucleotide, resulting in amino acid change from Asn to Ser. 2/3 in-silico tools predict this variant to be pathogenic. 3/3 in silico tools via Alamut predict loss of RNA splicing acceptor site and ESEFinder predicts gain of binding motifs for splicing enhancers. The variant was detected a a low frequency in the large and broad ExAC cohort (0.007%). This variant has been reported in 8 affected pts from a pedigree of families that are descendents of two separate couples. In this large pedigree, there is clear co-segregation of the variant with disease. (Edvardson_2013). A functional study showed this variant resulted in exon skipping and no functional SLC35A3 protein produced (Edvardson_ 2013). Taken together, this variant was classified as a Pathogenic. -
This sequence change replaces serine, which is neutral and polar, with glycine, which is neutral and non-polar, at codon 296 of the SLC35A3 protein (p.Ser296Gly). RNA analysis indicates that this missense change induces altered splicing and likely disrupts the C-terminus of the protein. This variant is present in population databases (rs141952252, gnomAD 0.1%). This missense change has been observed in individual(s) with autism spectrum disorder, epilepsy and arthrogryposis (PMID: 24031089). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 89030). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. Studies have shown that this missense change results in skipping of exon 7 and introduces a new termination codon (PMID: 24031089). However the mRNA is not expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic. -
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not provided Pathogenic:1
Published functional studies demonstrate that this variant results in skipping of exon 8 and is predicted to cause frame shift at the protein level, leading to an unstable, non-functional SLC35A3 protein (Edvardson S et al., 2013); Variant predicted to result in protein truncation, as the variant is predicted to result in the skipping of a portion of exon 8 resulting in a frameshift, and other loss-of-function variants have been reported; This variant is associated with the following publications: (PMID: 24031089) -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at