Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_001368894.2(PAX6):c.1075-2A>G variant causes a splice acceptor, intron change. The variant was absent in control chromosomes in GnomAD project. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).
PAX6 (HGNC:8620): (paired box 6) This gene encodes paired box protein Pax-6, one of many human homologs of the Drosophila melanogaster gene prd. In addition to a conserved paired box domain, a hallmark feature of this gene family, the encoded protein also contains a homeobox domain. Both domains are known to bind DNA and function as regulators of gene transcription. Activity of this protein is key in the development of neural tissues, particularly the eye. This gene is regulated by multiple enhancers located up to hundreds of kilobases distant from this locus. Mutations in this gene or in the enhancer regions can cause ocular disorders such as aniridia and Peter's anomaly. Use of alternate promoters and alternative splicing results in multiple transcript variants encoding different isoforms. Interestingly, inclusion of a particular alternate coding exon has been shown to increase the length of the paired box domain and alter its DNA binding specificity. Consequently, isoforms that carry the shorter paired box domain regulate a different set of genes compared to the isoforms carrying the longer paired box domain. [provided by RefSeq, Mar 2019]
PAX6 Gene-Disease associations (from GenCC):
aniridia 1
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
PAX6-related ocular dysgenesis
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
Our verdict: Pathogenic. The variant received 18 ACMG points.
PVS1
Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 6.7, offset of 7, new splice context is: tctctcctcacggcccccAGtcc. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 11-31790862-T-C is Pathogenic according to our data. Variant chr11-31790862-T-C is described in ClinVar as Pathogenic. ClinVar VariationId is 3468.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
The c.1033-2 A>G splice site variant in the PAX6 gene destroys the canonical splice acceptor site in intron 11. It is predicted to cause abnormal gene splicing, either leading to an abnormal message that is subject to nonsense-mediated mRNA decay, or to an abnormal protein product if the message is used for protein translation. Although this variant has not been previously reported to our knowledge, we interpret it as pathogenic. -