Both sequencing and deletion/duplication (CNV) analysis will be performed on the coding regions of the GBA gene. Seqeuncing is performed via long-range PCR followed by sequencing via NGS technology. Copy number variation (CNV) analysis, via MLPA, is used to detect deletions and duplications. All variants are classified according to American College of Genetics and Genomics (ACMG) guidelines.

Gaucher disease is associated with accumulation of harmful lipids throughout the body. There are 5 types of Gaucher disease. Type 1 Gaucher disease is the most common form with a variable age of onset and symptom severity. Symptoms typically include hepatosplenomegaly, anemia, easy bruising, lung disease, and bone abnormalities. Types 2 and 3 both affect the central nervous system and symptoms typically include those associated with Type 1 as well as abnormal eye movements and seizures. Type 2 Gaucher disease typically presents in infancy and progresses rapidly progresses, while Type 3 is associated with a slower progression. The perinatal lethal form of Gaucher disease is characterized by onset during pregnancy or in early infancy. Symptoms include hydrops fetalis, ichthyosis, skin abnormalities, hepatosplenomegaly, distinct facial features, and severe neurological phenotypes. Death usually occurs a few days after birth. The cardiovascular form of Gaucher disease is chartacterized by calcified heart valves, eye abnormalities, bone disease, and splenomegaly. The incidence of Gaucher disease is estimated to be 1 in 50,000.

Long-range PCR is performed to capture the true GBA genomic sequence from this individual’s genomic DNA to avoid pseudogene contaminants. PCR product was utilized to prepare the library and further sequenced using NGS technology on an Illumina system with 150 base pair paired-end reads. Indels and SNVs are confirmed by Sanger sequence analysis before reporting at director discretion. This analysis cannot detect variants in regions not analyzed such as promoters, deep intronic regions, or long repetitive regions. CNV analysis was assessed using MLPA or by manual review of NGS reads using IGV viewer. This analysis cannot determine the location or orientation of a duplication. Copy neutral gene conversion or fusion, complex rearrangement, or large deletion including the entire GBA gene with breakpoint(s) outside the targeted region may not be detected by this assay. This assay is not designed to detect mosaicism; possible cases of mosaicism may be investigated at the discretion of the laboratory director. Primary data analysis is performed using Illumina bcl2fastq converter v2.19. Secondary analysis is performed using Illumina DRAGEN Bio-IT Platform v.3.10.8. Tertiary data analysis is performed using SnpEff v5.0 and Revvity Omics’ internal ODIN v.1.01 software.