17-3481798-G-A
Variant summary
Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM2PP3_StrongPP5_Very_Strong
The NM_000049.4(ASPA):c.432G>A(p.Lys144Lys) variant causes a splice region, synonymous change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000082 in 1,586,074 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).
Frequency
Consequence
NM_000049.4 splice_region, synonymous
Scores
Clinical Significance
Conservation
Publications
- infertility disorderInheritance: AR Classification: MODERATE Submitted by: Ambry Genetics
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ACMG classification
Our verdict: Pathogenic. The variant received 14 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000658 AC: 1AN: 152072Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000215 AC: 5AN: 232326 AF XY: 0.0000319 show subpopulations
GnomAD4 exome AF: 0.00000837 AC: 12AN: 1434002Hom.: 0 Cov.: 29 AF XY: 0.0000112 AC XY: 8AN XY: 713266 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.00000658 AC: 1AN: 152072Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74294 show subpopulations
ClinVar
Submissions by phenotype
Spongy degeneration of central nervous system Pathogenic:2Uncertain:2
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This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 554976). This variant has been observed in individual(s) with Canavan disease (PMID: 21907889, 28101991). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is present in population databases (rs754087904, gnomAD 0.004%). This sequence change affects codon 144 of the ASPA mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the ASPA protein. This variant also falls at the last nucleotide of exon 2, which is part of the consensus splice site for this exon. -
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Canavan Disease, Familial Form Pathogenic:1
Variant summary: ASPA c.432G>A (p.Lys144Lys) alters a conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Several computational tools predict a significant impact on normal splicing: One predicts the variant abolishes a 5 splicing donor site. Two predict the variant weakens a 5' donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 2.2e-05 in 232326 control chromosomes (gnomAD). c.432G>A has been reported in the literature in individuals affected with Canavan Disease (examples: Schober_2011, Mendes_2017, Ashrafi_2023), although one of the reported cases was mild, and to explain the atypical phenotype, authors proposed a leaky splice effect for the variant, but provided no mRNA studies to confirm this hypothesis (Mendes_2017). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 28101991, 21907889, 37597066). ClinVar contains an entry for this variant (Variation ID: 554976). Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at