Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2PP3_Moderate
The NM_006279.5(ST3GAL3):c.118+5G>A variant causes a splice donor 5th base, intron change. The variant allele was found at a frequency of 0.00000372 in 1,614,066 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).
ST3GAL3 (HGNC:10866): (ST3 beta-galactoside alpha-2,3-sialyltransferase 3) The protein encoded by this gene is a type II membrane protein that catalyzes the transfer of sialic acid from CMP-sialic acid to galactose-containing substrates. The encoded protein is normally found in the Golgi apparatus but can be proteolytically processed to a soluble form. This protein is a member of glycosyltransferase family 29. Mutations in this gene have been associated with a form of autosomal recessive nonsymdromic cognitive disability as well as infantile epileptic encephalopathy. Multiple transcript variants encoding several different isoforms have been found for this gene. [provided by RefSeq, Jul 2017]
Uncertain significance, criteria provided, single submitter
clinical testing
Genetic Services Laboratory, University of Chicago
Aug 17, 2015
- -
Early infantile epileptic encephalopathy with suppression bursts Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Labcorp Genetics (formerly Invitae), Labcorp
Jul 19, 2022
This sequence change falls in intron 2 of the ST3GAL3 gene. It does not directly change the encoded amino acid sequence of the ST3GAL3 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs759128744, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with ST3GAL3-related conditions. ClinVar contains an entry for this variant (Variation ID: 436872). 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 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. -