chr11-66523882-G-A
Variant summary
Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM2PP3PP5_Very_Strong
The NM_024649.5(BBS1):c.1110G>A(p.Pro370Pro) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000093 in 1,612,874 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_024649.5 splice_region, synonymous
Scores
Clinical Significance
Conservation
Publications
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ACMG classification
Our verdict: Pathogenic. The variant received 11 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| BBS1 | ENST00000318312.12 | c.1110G>A | p.Pro370Pro | splice_region_variant, synonymous_variant | Exon 11 of 17 | 1 | NM_024649.5 | ENSP00000317469.7 | ||
| ENSG00000256349 | ENST00000419755.3 | c.1221G>A | p.Pro407Pro | splice_region_variant, synonymous_variant | Exon 11 of 17 | 2 | ENSP00000398526.3 |
Frequencies
GnomAD3 genomes AF: 0.0000329 AC: 5AN: 152192Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000120 AC: 3AN: 249712 AF XY: 0.0000222 show subpopulations
GnomAD4 exome AF: 0.00000685 AC: 10AN: 1460564Hom.: 0 Cov.: 31 AF XY: 0.0000110 AC XY: 8AN XY: 726634 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000328 AC: 5AN: 152310Hom.: 0 Cov.: 32 AF XY: 0.0000537 AC XY: 4AN XY: 74476 show subpopulations
ClinVar
Submissions by phenotype
Bardet-Biedl syndrome Pathogenic:2
This sequence change affects codon 370 of the BBS1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the BBS1 protein. This variant also falls at the last nucleotide of exon 11, which is part of the consensus splice site for this exon. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has been observed in individuals with BBS1-related conditions (PMID: 16877420, 23432027; internal data). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 553357). 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. 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. -
Variant summary: BBS1 c.1110G>A (p.Pro370Pro) 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. Three predict the variant weakens a 5' donor site. Three predict the variant creates a 3' acceptor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 1.2e-05 in 249712 control chromosomes (gnomAD). c.1110G>A has been observed in individuals affected with Bardet-Biedl Syndrome (Smaoui_2006, Redin_2012, Mhamdi_2013, internal data). 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: 31836858, 23432027, 22773737, 16877420, 28341476). ClinVar contains an entry for this variant (Variation ID: 553357). Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Bardet-Biedl syndrome 1 Pathogenic:1Uncertain:1
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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. -
not provided Pathogenic:1
This variant is associated with the following publications: (PMID: 16877420, 23432027, 22773737) -
BBS1-related disorder Uncertain:1
The BBS1 c.1110G>A variant is not predicted to result in an amino acid change (p.=). This variant occurs at the last nucleotide of exon 11 and is predicted to alter splicing based on available splicing prediction programs (SpliceAI, Jaganathan et al. 2019. PubMed ID: 30661751). However, the use of computer prediction programs is not equivalent to functional evidence. This variant has been reported in the homozygous state in at least one individual of Tunisian ancestry with Bardet-Biedl syndrome; however, no additional evidence was provided to support its pathogenicity (Table 2, Smaoui et al. 2006. PubMed ID: 16877420; Table 3, Redin et al. 2012. PubMed ID: 22773737; Table 2, M'hamdi et al. 2014. PubMed ID: 23432027). This variant is reported in 0.0050% of alleles in individuals of East Asian descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at