Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2PM5PP3_Moderate
The NM_017777.4(MKS1):c.857A>T(p.Asp286Val) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.00000137 in 1,461,732 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D286G) has been classified as Pathogenic.
MKS1 (HGNC:7121): (MKS transition zone complex subunit 1) The protein encoded by this gene localizes to the basal body and is required for formation of the primary cilium in ciliated epithelial cells. Mutations in this gene result in Meckel syndrome type 1 and in Bardet-Biedl syndrome type 13. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2009]