Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BS1_SupportingBS2
The NM_003919.3(SGCE):c.409C>T(p.Arg137Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000499 in 1,602,254 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R137H) has been classified as Likely benign.
SGCE (HGNC:10808): (sarcoglycan epsilon) This gene encodes the epsilon member of the sarcoglycan family. Sarcoglycans are transmembrane proteins that are components of the dystrophin-glycoprotein complex, which link the actin cytoskeleton to the extracellular matrix. Unlike other family members which are predominantly expressed in striated muscle, the epsilon sarcoglycan is more broadly expressed. Mutations in this gene are associated with myoclonus-dystonia syndrome. This gene is imprinted, with preferential expression from the paternal allele. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. A pseudogene associated with this gene is located on chromosome 2. [provided by RefSeq, Oct 2016]
CASD1 (HGNC:16014): (CAS1 domain containing 1) Enables N-acetylneuraminate 7-O(or 9-O)-acetyltransferase activity. Involved in carbohydrate metabolic process. Is integral component of Golgi membrane. [provided by Alliance of Genome Resources, Apr 2022]
Verdict is Likely_benign. Variant got -5 ACMG points.
BS1
Variant frequency is greater than expected in population amr. gnomad4 allele frequency = 0.0000657 (10/152106) while in subpopulation AMR AF= 0.000458 (7/15270). AF 95% confidence interval is 0.000215. There are 0 homozygotes in gnomad4. There are 7 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 137 of the SGCE protein (p.Arg137Cys). This variant is present in population databases (rs557861177, gnomAD 0.04%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with cranial dystonia (PMID: 35041927). ClinVar contains an entry for this variant (Variation ID: 464155). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt SGCE protein function with a negative predictive value of 80%. 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. -
not provided Uncertain:1
Jan 01, 2025
CeGaT Center for Human Genetics Tuebingen
Significance: Uncertain significance
Review Status: criteria provided, single submitter
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