On this page
GBA
glucosylceramidase beta 1
The GBA gene provides instructions for producing the lysosomal acid glucosylceramidase enzyme, crucial for breaking down a fatty molecule called glucocerebroside within cells. The GBA gene is responsible for encoding the lysosomal acid glucosylceramidase enzyme, a key component in the cell's recycling centres known as lysosomes.
GBA is located on the long (q) arm of chromosome 1, at band 1q22. Arm ratio per GRCh38 - banding schematic.
Explore chromosome 1 in the library →Available at Jeen Health
Clinical tests that include this
Overview
The GBA gene, also known as glucosylceramidase beta 1, is essential for normal cellular function. It contains the genetic blueprint for lysosomal acid glucosylceramidase, an enzyme that plays a vital role in the breakdown and recycling of cellular waste products [PMID:28777044]. This enzyme's activity is centred in the lysosomes, which are specialised compartments within cells that act as digestive and recycling units.
Efficient functioning of the GBA gene is critical for preventing the accumulation of certain fatty substances within cells. When the enzyme is deficient or non-functional due to genetic variants, these substances can build up, leading to various health issues. The most well-known condition associated with GBA variants is Gaucher disease, an inherited metabolic disorder [PMID:31838874].
What the gene does
The GBA gene provides instructions for synthesising lysosomal acid glucosylceramidase. This enzyme functions within lysosomes, cellular organelles vital for waste processing and recycling [PMID:28777044]. Lysosomes contain various digestive enzymes that break down cellular debris, harmful substances, and worn-out components. These enzymes are sometimes referred to as housekeeping enzymes.
Glucosylceramidase plays a crucial role by cleaving glucocerebroside, a large lipid molecule found in cell membranes. It converts glucocerebroside into its constituent parts: glucose, a simple sugar, and ceramide, another lipid. This breakdown is essential because as cells die, their membrane components, including glucocerebroside, must be efficiently recycled to enable the formation of new cells.
If genetic changes in GBA impair the full function of the lysosomal acid glucosylceramidase enzyme, glucocerebroside can accumulate within lysosomes. This build-up disrupts normal cellular processes and can lead to the characteristic symptoms observed in associated conditions such as Gaucher disease.
Video: Genetics 101
Chromosome location
The GBA gene is situated on the long arm of chromosome 1, specifically at position 1q22. This chromosomal location indicates that the gene resides within the first chromosome, in region 2, band 2 on the q arm. The precise location on the chromosome ensures its organised expression and function within the human genome.
Protein structure
The protein encoded by the GBA gene, lysosomal acid glucosylceramidase, is composed of 536 amino acids.
Key variants
Variants within the GBA gene can alter the production or function of the lysosomal acid glucosylceramidase enzyme [PMID:31838874]. These genetic changes can range from single nucleotide substitutions to larger deletions or insertions within the gene sequence. Depending on their nature and location, variants can lead to a partial reduction in enzyme activity or a complete loss of function. The specific impact of a variant often influences the severity and presentation of associated conditions. Individuals can carry different combinations of variants, further contributing to the diverse clinical spectrum observed.
No pathogenic or likely-pathogenic ClinVar variants recorded yet for this gene.
Associated conditions
Variants in the GBA gene are predominantly associated with Gaucher disease, an inherited lysosomal storage disorder that presents in several forms: Gaucher disease type 1, Gaucher disease type 2 (acute neuronopathic), and Gaucher disease type 3 (chronic neuronopathic) [PMID:28777044]. Individuals affected can experience an enlarged liver and spleen (hepatosplenomegaly) and abnormalities in blood cell counts. Additionally, changes in the GBA gene have been linked to an increased risk for Parkinson disease (idiopathic), a movement disorder characterised by tremors and impaired balance [PMID:31838874]. There is also an association with dementia with Lewy bodies, which involves intellectual decline, visual hallucinations, and sudden changes in attention and cognition.
Inheritance pattern
Conditions caused by pathogenic GBA variants typically follow autosomal recessive inheritance.
When both parents are carriers, each child has a 25% chance of being affected, 50% of being a carrier, and 25% of being unaffected.
UK clinical status
In the UK, the GBA gene is included in several NHS Genomic Medicine Service national test directory panels, indicating its recognised clinical significance. It is covered for conditions such as Gaucher disease, lysosomal storage disorder, and Parkinson Disease and Complex Parkinsonism. The gene is also assessed in panels for various neurological and metabolic disorders, including early onset or syndromic epilepsy and likely inborn errors of metabolism, highlighting its broad relevance in genetic diagnostics.
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Diet & lifestyle considerations
Research suggests that while lifestyle choices cannot alter the genetic basis of GBA-related conditions, they may play a supportive role in overall health management. For individuals with GBA variants, maintaining a balanced diet rich in fruits, vegetables, and whole grains is generally recommended for good health. Regular physical activity, tailored to individual capabilities, may also contribute to well-being. However, these are general health recommendations and do not specifically target the genetic mechanisms of GBA-associated conditions.
Supplement considerations
No conclusive evidence suggests that specific supplements can prevent or treat GBA-associated conditions. While certain supplements are often marketed for general neurological health or metabolic support, their effectiveness in the context of GBA variants has not been established through rigorous clinical trials. Any individual considering supplements should discuss this with a healthcare provider, particularly due to potential interactions with existing medications or other health conditions.
Frequently asked questions
What is the primary function of the GBA gene?
The GBA gene provides instructions for the lysosomal acid glucosylceramidase enzyme, which is crucial for breaking down the fatty molecule glucocerebroside within the cell's lysosomes.
Which diseases are associated with variants in the GBA gene?
Variants in the GBA gene are primarily associated with Gaucher disease, including types 1, 2, and 3. They are also linked to an increased risk for Parkinson disease and dementia with Lewy bodies.
How do GBA gene variants cause Gaucher disease?
Variants in the GBA gene lead to a deficiency or malfunction of the lysosomal acid glucosylceramidase enzyme. This causes glucocerebroside to accumulate in lysosomes, impairing cellular function and leading to the symptoms of Gaucher disease.
Is GBA gene testing available in the UK?
Yes, the GBA gene is included in several NHS Genomic Medicine Service national test directory panels for conditions like Gaucher disease, lysosomal storage disorders, and Parkinson Disease.
Can lifestyle changes or supplements cure GBA-related conditions?
No, lifestyle changes or supplements cannot cure GBA-related genetic conditions. While a healthy lifestyle supports overall well-being, and supplements might be considered for general health, no evidence suggests they specifically treat or prevent GBA-associated disorders. Always consult a healthcare provider before taking any supplements.
References
- Nalls MA, Duran R, Lopez G. A multicenter study of glucocerebrosidase mutations in dementia with Lewy bodies. JAMA neurology. 2013. PMID: 23588557
- Tsuang D, Leverenz JB, Lopez OL. GBA mutations increase risk for Lewy body disease with and without Alzheimer disease pathology. Neurology. 2012. PMID: 23035075
- Velayati A, Yu WH, Sidransky E. The role of glucocerebrosidase mutations in Parkinson disease and Lewy body disorders. Current neurology and neuroscience reports. 2010. PMID: 20425034
- Clark LN, Kartsaklis LA, Wolf Gilbert R. Association of glucocerebrosidase mutations with dementia with lewy bodies. Archives of neurology. 2009. PMID: 19433657
- Sidransky E, Nalls MA, Aasly JO. Multicenter analysis of glucocerebrosidase mutations in Parkinson's disease. The New England journal of medicine. 2009. PMID: 19846850
- Mata IF, Samii A, Schneer SH. Glucocerebrosidase gene mutations: a risk factor for Lewy body disorders. Archives of neurology. 2008. PMID: 18332251
- Clark LN, Ross BM, Wang Y. Mutations in the glucocerebrosidase gene are associated with early-onset Parkinson disease. Neurology. 2007. PMID: 17875915
- Goker-Alpan O, Giasson BI, Eblan MJ. Glucocerebrosidase mutations are an important risk factor for Lewy body disorders. Neurology. 2006. PMID: 16790605
- Sidransky E. Heterozygosity for a Mendelian disorder as a risk factor for complex disease. Clinical genetics. 2006. PMID: 16965318
- Pelled D, Trajkovic-Bodennec S, Lloyd-Evans E. Enhanced calcium release in the acute neuronopathic form of Gaucher disease. Neurobiology of disease. 2005. PMID: 15649698
- Jmoudiak M, Futerman AH. Gaucher disease: pathological mechanisms and modern management. British journal of haematology. 2005. PMID: 15813845
- Charrow J, Andersson HC, Kaplan P. Enzyme replacement therapy and monitoring for children with type 1 Gaucher disease: consensus recommendations. The Journal of pediatrics. 2004. PMID: 14722528
- Germain DP. Gaucher's disease: a paradigm for interventional genetics. Clinical genetics. 2004. PMID: 14984463
- Sidransky E. Gaucher disease: complexity in a "simple" disorder. Molecular genetics and metabolism. 2004. PMID: 15464415
- Aharon-Peretz J, Rosenbaum H, Gershoni-Baruch R. Mutations in the glucocerebrosidase gene and Parkinson's disease in Ashkenazi Jews. The New England journal of medicine. 2004. PMID: 15525722
- Orvisky E, Park JK, Parker A. The identification of eight novel glucocerebrosidase (GBA) mutations in patients with Gaucher disease. Human mutation. 2002. PMID: 11933202
- Cox TM. Gaucher disease: understanding the molecular pathogenesis of sphingolipidoses. Journal of inherited metabolic disease. 2001. PMID: 11758671