Use long-range PCR and NGS method to detect GBA variations. This test analyzes the GBA gene that has been associated with Gaucher disease. All variants are classified according to ACMG guidelines.

• People with definite symptoms of related genetic diseases.
• People with a family history of related genetic disorders.

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. Type 2 and Type 3 Gaucher disease both affect the central nervous system and symptoms typically include the symptoms of Type 1 Gaucher disease plus abnormal eye movements, seizures, and brain damage. Type 2 Gaucher disease typically onsets in infancy and rapidly progresses, while Type 3 Gaucher disease typically progresses slower. The perinatal lethal form of Gaucher disease has symptom onset during pregnancy or in early infancy. Symptoms include hydrops fetalis, ichthyosis, skin abnormalities, hepatosplenomegaly, distinct facial features, and severe neurological problems. Death usually occurs a few days after birth. The cardiovascular form of Gaucher disease typically show symptoms of calcified heart valves, eye abnormalities, bone disease, and splenomegaly. The incidence of Gaucher disease is estimated to be ~ 1 in 50,000.

This test uses Long-range PCR and next-generation sequencing technology. Sequencing is performed on genomic DNA. Direct sequencing of the amplified captured regions was performed on Illumina next generation sequencing (NGS) systems. A base is considered to have sufficient coverage at 20X and an exon is considered fully covered if all coding bases plus three nucleotides of flanking sequence on either side are covered at 20X or more. Low coverage regions, if any, are limited to ~1% or less of the nucleotides in the test unless a pathogenic variant explaining the phenotype is discovered. A list of these regions is available upon request. Alignment to the human reference genome (hg19) is performed and annotated variants are identified in the targeted region. Variants are called at a minimum coverage of 8X and an alternate allele frequency of 20% or higher. Single nucleotide variants (SNVs) meeting internal quality assessment guidelines are confirmed by Sanger sequence analysis for records after results are reported. Indels and SNVs are confirmed by Sanger sequence analysis before reporting at director discretion. This assay cannot detect variants in regions of the exome that are not covered, such as deep intronic, promoter and enhancer regions, areas containing large numbers of tandem repeats, and variants in mitochondrial DNA. Copy number variation (CNV) analysis detects deletions and duplications; in some instances, due to the size of the exons, sequence complexity, or other factors, not all CNVs may be analyzed or may be difficult to detect.