title: GBA p.T369M substitution in Parkinson disease: Polymorphism or association? A meta-analysis.
abstract: The lysosomal enzyme glucocerebrosidase (GCase), encoded by GBA, has an important role in Parkinson disease (PD). GBA mutation carriers have an increased risk for PD, earlier age at onset, faster progression, and various nonmotor symptoms including cognitive decline, REM sleep behavior disorder, hyposmia, and autonomic dysfunction.(1) Furthermore, GCase enzymatic activity is reduced in the peripheral blood(2) and brain(3) of noncarrier, sporadic PD patients. Biallelic GBA mutations, which have been classified as "severe" or "mild," may cause Gaucher disease (GD), a lysosomal storage disorder. Mild mutations may lead to GD type 1, and 2 severe mutations result in neuronopathic GD (type 2 and type 3).(4) There are 2 GBA variants, p.E326K and p.T369M, which do not cause GD in homozygous carriers, but may modify GCase activity and GD phenotype. It is now clear that p.E326K is a risk factor for PD,(5) but whether p.T369M is associated with PD is still controversial. In some studies, the p.T369M substitution was associated with PD,(6) while in others it had similar or increased frequency in controls. Of interest, it was recently demonstrated that the GBA p.T369M substitution was associated with reduced enzymatic activity in patients with PD and controls compared with that in noncarriers (7.64 vs 11.93 μmol/L/h, p < 0.001).(2) Of interest, it was even lower than the average enzymatic activity of the p.E326K substitution, which was 9.81 μmol/L/h. Because clinical trials on GBA-associated PD are ongoing, and because treatment specifically targeting GBA is likely to be available in the future, it is important to determine whether the GBA p.T369M substitution is associated with PD.
authors.affiliation: Montreal Neurological Institute (V.M., J.P.R., A.A., P.A.D., G.A.R., Z.G.-O.), Department of Human Genetics (J.P.R., A.A., G.A.R., Z.G.-O.), Department of Neurology and Neurosurgery (P.A.D., G.A.R., Z.G.-O.), McGill University, Quebec, Canada; Department of Neurology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (R.N.A.), College of Physicians and Surgeons, Columbia University, New York, NY; and Section on Molecular Neurogenetics (E.S.), Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Victoria
authors.initials: V
authors.lastname: Mallett
authors.affiliation: Montreal Neurological Institute (V.M., J.P.R., A.A., P.A.D., G.A.R., Z.G.-O.), Department of Human Genetics (J.P.R., A.A., G.A.R., Z.G.-O.), Department of Neurology and Neurosurgery (P.A.D., G.A.R., Z.G.-O.), McGill University, Quebec, Canada; Department of Neurology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (R.N.A.), College of Physicians and Surgeons, Columbia University, New York, NY; and Section on Molecular Neurogenetics (E.S.), Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Jay P
authors.initials: JP
authors.lastname: Ross
authors.affiliation: Montreal Neurological Institute (V.M., J.P.R., A.A., P.A.D., G.A.R., Z.G.-O.), Department of Human Genetics (J.P.R., A.A., G.A.R., Z.G.-O.), Department of Neurology and Neurosurgery (P.A.D., G.A.R., Z.G.-O.), McGill University, Quebec, Canada; Department of Neurology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (R.N.A.), College of Physicians and Surgeons, Columbia University, New York, NY; and Section on Molecular Neurogenetics (E.S.), Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Roy N
authors.initials: RN
authors.lastname: Alcalay
authors.affiliation: Montreal Neurological Institute (V.M., J.P.R., A.A., P.A.D., G.A.R., Z.G.-O.), Department of Human Genetics (J.P.R., A.A., G.A.R., Z.G.-O.), Department of Neurology and Neurosurgery (P.A.D., G.A.R., Z.G.-O.), McGill University, Quebec, Canada; Department of Neurology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (R.N.A.), College of Physicians and Surgeons, Columbia University, New York, NY; and Section on Molecular Neurogenetics (E.S.), Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Amirthagowri
authors.initials: A
authors.lastname: Ambalavanan
authors.affiliation: Montreal Neurological Institute (V.M., J.P.R., A.A., P.A.D., G.A.R., Z.G.-O.), Department of Human Genetics (J.P.R., A.A., G.A.R., Z.G.-O.), Department of Neurology and Neurosurgery (P.A.D., G.A.R., Z.G.-O.), McGill University, Quebec, Canada; Department of Neurology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (R.N.A.), College of Physicians and Surgeons, Columbia University, New York, NY; and Section on Molecular Neurogenetics (E.S.), Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Ellen
authors.initials: E
authors.lastname: Sidransky
authors.affiliation: Montreal Neurological Institute (V.M., J.P.R., A.A., P.A.D., G.A.R., Z.G.-O.), Department of Human Genetics (J.P.R., A.A., G.A.R., Z.G.-O.), Department of Neurology and Neurosurgery (P.A.D., G.A.R., Z.G.-O.), McGill University, Quebec, Canada; Department of Neurology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (R.N.A.), College of Physicians and Surgeons, Columbia University, New York, NY; and Section on Molecular Neurogenetics (E.S.), Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Dion
authors.affiliation: Montreal Neurological Institute (V.M., J.P.R., A.A., P.A.D., G.A.R., Z.G.-O.), Department of Human Genetics (J.P.R., A.A., G.A.R., Z.G.-O.), Department of Neurology and Neurosurgery (P.A.D., G.A.R., Z.G.-O.), McGill University, Quebec, Canada; Department of Neurology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (R.N.A.), College of Physicians and Surgeons, Columbia University, New York, NY; and Section on Molecular Neurogenetics (E.S.), Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Guy A
authors.initials: GA
authors.lastname: Rouleau
authors.affiliation: Montreal Neurological Institute (V.M., J.P.R., A.A., P.A.D., G.A.R., Z.G.-O.), Department of Human Genetics (J.P.R., A.A., G.A.R., Z.G.-O.), Department of Neurology and Neurosurgery (P.A.D., G.A.R., Z.G.-O.), McGill University, Quebec, Canada; Department of Neurology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain (R.N.A.), College of Physicians and Surgeons, Columbia University, New York, NY; and Section on Molecular Neurogenetics (E.S.), Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD.
authors.forename: Ziv
authors.initials: Z
authors.lastname: Gan-Or