Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2
The NM_003896.4(ST3GAL5):āc.362G>Cā(p.Arg121Pro) variant causes a missense change. The variant allele was found at a frequency of 0.0000031 in 1,614,074 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (ā ). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R121C) has been classified 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]
Verdict is Uncertain_significance. Variant got 2 ACMG points.
PM2
?
PM2 - Absent from controls (or at extremely low frequency if recessive) in Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium
Very rare variant in population databases, with high coverage;
Uncertain significance, criteria provided, single submitter
clinical testing
Ambry Genetics
Dec 14, 2022
The c.362G>C (p.R121P) alteration is located in exon 4 (coding exon 4) of the ST3GAL5 gene. This alteration results from a G to C substitution at nucleotide position 362, causing the arginine (R) at amino acid position 121 to be replaced by a proline (P). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -