Parkinson's Disease and Fabry Disease: Clinical, Biochemical and Neuroimaging Analysis of Three Pedigrees

Background:

Sporadic Parkinson’s disease (PD) patients have lower α-galactosidase A (α-GAL A) enzymatic activity and Fabry disease (FD) patients potentially carry an increased risk of PD.

Objective:

Determination of PD prevalence in FD and clinical, biochemical and vascular neuroimaging description of FD pedigrees with concomitant PD.

Methods:

Clinical screening for PD in 229 FD patients belonging to 31 families, harbouring GLA gene mutation p.F113L, and subsequent pedigree analysis. Gender-stratified comparison of FD+/PD+ patients with their family members with FD but without PD (FD+/PD–) regarding Mainz scores, plasma & leukocytes α-GAL A enzymatic activity, urinary Gb3 and plasma Lyso-Gb3, vascular brain neuroimaging.

Results:

Prevalence of PD in FD was 1.3% (3/229) (3% in patients aged ≥50 years). Three FD patients, one female (73 years old) (P1) and two males (60 and 65 years old) (P2 and P3), three different pedigrees, presented akinetic-rigid PD, with weak response to levodopa (16% – 36%), and dopaminergic deficiency on 18F-DOPA PET. No pathogenic mutations were found in a PD gene panel. FD+/PD+ patients had worse clinical severity of FD (above upper 75% IQR in Mainz scores), and cortico-subcortical white matter/small vessel lesions. P3 patient was under enzyme therapy, started 1 year before PD diagnosis. P2-P3 patients had higher leucocyte α-GAL A activity (2,2-3 vs.1,0 (median)(nmol/h/mg)).

Conclusion:

We have shown a high prevalence of PD in a late-onset phenotype of FD, presenting high cerebrovascular burden and weak response to levodopa. Further studies will untangle how much of this PD phenotype is due to Gb3 deposition versus cerebrovascular lesions in the nigro-striatal network.

Fabry Disease Therapy: State-of-the-Art and Current Challenges

Fabry disease (FD) is a lysosomal storage disorder caused by mutations of the GLA gene that lead to a deficiency of the enzymatic activity of α-galactosidase A. Available therapies for FD include enzyme replacement therapy (ERT) (agalsidase alfa and agalsidase beta) and the chaperone migalastat. Despite the large body of literature published about ERT over the years, many issues remain unresolved, such as the optimal dose, the best timing to start therapy, and the clinical impact of anti-drug antibodies. Migalastat was recently approved for FD patients with amenable GLA mutations; however, recent studies have raised concerns that "in vitro" amenability may not always reflect "in vivo" amenability, and some findings on real-life studies have contrasted with the results of the pivotal clinical trials. Moreover, both FD specific therapies present limitations, and the attempt to correct the enzymatic deficiency, either by enzyme exogenous administration or enzyme stabilization with a chaperone, has not shown to be able to fully revert FD pathology and clinical manifestations. Therefore, several new therapies are under research, including new forms of ERT, substrate reduction therapy, mRNA therapy, and gene therapy. In this review, we provide an overview of the state-of-the-art on the currently approved and emerging new therapies for adult patients with FD.

Different protocols for analyzing behavior and adaptability in obstacle crossing in Parkinson's disease

Imbalance and tripping over obstacles as a result of altered gait in older adults, especially in patients with Parkinson’s disease (PD), are one of the most common causes of falls. During obstacle crossing, patients with PD modify their behavior in order to decrease the mechanical demands and enhance dynamic stability. Various descriptions of dynamic traits of gait that have been collected over longer periods, probably better synthesize the underlying structure and pattern of fluctuations in gait and can be more sensitive markers of aging or early neurological dysfunction and increased risk of falls. This confirmation challenges the clinimetric of different protocols and paradigms used for gait analysis up till now, in particular when analyzing obstacle crossing. The authors here present a critical review of current knowledge concerning the interplay between the cognition and gait in aging and PD, emphasizing the differences in gait behavior and adaptability while walking over different and challenging obstacle paradigms, and the implications of obstacle negotiation as a predictor of falls. Some evidence concerning the effectiveness of future rehabilitation protocols on reviving obstacle crossing behavior by trial and error relearning, taking advantage of dual-task paradigms, physical exercise, and virtual reality have been put forward in this article.

[Cerebrospinal fluid biomarkers for the early diagnosis of Parkinson's disease]

In current medical practice, the diagnosis of Parkinson's disease remains essentially clinical. This practice determines that the diagnosis of Parkinson's disease is done in an already advanced neuropathological stage of the disease. The aim of this study is to review the validity of cerebrospinal fluid protein biological markers in the early diagnosis of Parkinson's disease. The a-synuclein and DJ-1 proteins, due to their role in the hereditary Parkinson's disease, have been the most widely studied cerebrospinal biomarkers. Nevertheless, they have had divergent results mostly owing to different processing, identification and control of laboratory techniques. The new proteomic techniques, directed to the detection of multiple undifferentiated proteins in cerebrospinal fluid (eg. ceruloplasmin, chromogranin B, apoH), are promising. The early diagnosis of Parkinson's disease is imperious as it is a progressive neurodegenerative disorder that causes extensive morbidity. Most of current scientific research in Parkinson's disease is focused on the discovery of neuroprotective drugs. Thus, the definition of biomarkers for the early diagnosis of Parkinson's disease is highly relevant.

SANDO: Two novel mutations in POLG1 gene

Sensory ataxia with neuropathy, dysarthria and ophthalmoparesis represent the clinical triad of SANDO, a specific mitochondrial phenotype first reported in 1997 in association with multiple mitochondrial DNA deletions and mutations in POLG1 or more rarely in the C10orf2 (twinkle-helicase) gene. We report a 44-year-old man with SANDO who harboured two novel mutations (P648R/R807C) in the POLG1 gene.