Description
The p.Asn409Ser variant in GBA has been reported in about 80% of all individuals with Gaucher disease with an increased prevalence in the affected Ashkenazi Jewish population, and has segregated with disease in 7 affected relatives from 3 families (PMID: 14757438, 17427031, 20301446). The variant has been identified in 2.691% (279/10368) of Ashkenazi Jewish chromosomes, including 2 homozygotes. Although this variant has been seen in the general population, its frequency is not high enough to rule out a pathogenic role due to the variable phenotypic presentation of this variant. This variant has also been reported in ClinVar (VariationID: 4290) as a VUS by Praxis fuer Humangenetik Tuebingen, as likely pathogenic by University Medical Centre Ljubljana, as Pathogenic by Genetic Services Laboratory, GeneDx, Illumina Clinical Services, Counsyl, Knight Diagnostic Laboratories, EGL Genetic Diagnostics, Fulgent Genetics, Integrated Genetics, Shahid Beheshti University of Medical Sciences, Mayo Clinic Genetic Testing Laboratories, Children's Hospital of Philadelphia, and OMIM. In vitro functional studies showing reduced enzymatic activity, increased a-synuclein concentration, restoration of enzymatic activity through molecular chaperones, and a shifted optimal pH for enzymatic activity provide some evidence that the p.Asn409Ser variant may impact protein function (PMID: 14757438, 21472771, 28923368, 20980259). However, these types of assays may not accurately represent biological function. Additionally, animal models in mice demonstrating enzyme properties comparable to those in human Gaucher patients have shown that this variant causes Gaucher disease (PMID: 16293621). Computational prediction tools and conservation analyses do not provide strong support for or against an impact to the protein. The phenotype of an individual homozygous or compound heterozygous for this variant is highly specific for Gaucher disease based on hepatomegaly, splenomegaly, and low residual enzyme activity consistent with disease (PMID: 14757438). The p.Asn409Ser variant is located in a region of GBA that is essential to protein folding and stability, suggesting that this variant is in a functional domain and supports pathogenicity (PMID: 20980259, 16293621, 14757438, 28923368). Additionally, the presence of this variant in at least 26 homozygotes and in combination with reported pathogenic variants in at least 65 individuals with Gaucher disease increases the likelihood that the p.Asn409Ser variant is pathogenic (VariationID: 4288, 93459; PMID: 17427031, 14757438). The p.Asn409Ser variant is pathogenic based off of our findings, multiple reports in ClinVar, and the literature. ACMG/AMP Criteria applied: PM3_very-strong, PS3, PM1, PP1_moderate, PP4 (Richards 2015).
| # | Sample | Method | Observation |
|---|
| Origin | Affected | Number tested | Tissue | Purpose | Method | Individuals | Allele frequency | Families | Co-occurrences |
|---|
| 1 | germline | unknown | not provided | not provided | not provided | | not provided | not provided | not provided | not provided |
