Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2
The NM_003896.4(ST3GAL5):c.1076C>T(p.Ala359Val) variant causes a missense change. The variant allele was found at a frequency of 0.000057 in 1,613,734 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).
ST3GAL5 (HGNC:10872): (ST3 beta-galactoside alpha-2,3-sialyltransferase 5) Ganglioside GM3 is known to participate in the induction of cell differentiation, modulation of cell proliferation, maintenance of fibroblast morphology, signal transduction, and integrin-mediated cell adhesion. The protein encoded by this gene is a type II membrane protein which catalyzes the formation of GM3 using lactosylceramide as the substrate. The encoded protein is a member of glycosyltransferase family 29 and may be localized to the Golgi apparatus. Mutation in this gene has been associated with Amish infantile epilepsy syndrome. Transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 359 of the ST3GAL5 protein (p.Ala359Val). This variant is present in population databases (rs201425015, gnomAD 0.02%). This variant has not been reported in the literature in individuals affected with ST3GAL5-related conditions. ClinVar contains an entry for this variant (Variation ID: 578981). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C55". The valine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -