Genome-wide Analysis of Motor Progression in Parkinson Disease

Background and Objectives

The genetic basis of Parkinson disease (PD) motor progression is largely unknown. Previous studies of the genetics of PD progression have included small cohorts and shown a limited overlap with genetic PD risk factors from case-control studies. Here, we have studied genomic variation associated with PD motor severity and early-stage progression in large longitudinal cohorts to help to define the biology of PD progression and potential new drug targets.

Methods

We performed a GWAS meta-analysis of early PD motor severity and progression up to 3 years from study entry. We used linear mixed-effect models with additive effects, corrected for age at diagnosis, sex, and the first 5 genetic principal components to assess variability in axial, limb, and total Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) III scores.

Results

We included 3,572 unrelated European ancestry patients with PD from 5 observational cohorts and 1 drug trial. The average AAO was 62.6 years (SD = 9.83), and 63% of participants were male. We found an average increase in the total MDS-UPDRS III score of 2.3 points/year. We identified an association between PD axial motor progression and variation at the GJA5 locus at 1q12 (β = -0.25, SE = 0.04, p = 3.4e-10). Exploration of the regulation of gene expression in the region (cis-expression quantitative trait loci [eQTL] analysis) showed that the lead variant was associated with expression of ACP6, a lysophosphatidic acid phosphatase that regulates mitochondrial lipid biosynthesis (cis-eQTL p-values in blood and brain RNA expression data sets: <10-14 in eQTLGen and 10-7 in PsychEncode).

Discussion

Our study highlights the potential role of mitochondrial lipid homeostasis in the progression of PD, which may be important in establishing new drug targets that might modify disease progression.

Acidosis correction with a new 25 mmol/l bicarbonate/15 mmol/l lactate peritoneal dialysis solution

OBJECTIVE

The aim of this study was to evaluate the effects of a combined 25 mmol/L bicarbonate/15 mmol/L lactate-based solution (Bic/Lac), compared to a 35 mmol/L lactate solution (Lac)--the most commonly used solution for patients in southern Europe--on the venous plasma bicarbonate level in patients treated with continuous ambulatory peritoneal dialysis (CAPD).

DESIGN

This was a randomized, parallel, controlled, open-label study, with patients studied for a period of 3 months preceded by a 1-month baseline and followed by a 1-month follow-up. Patients used the 35 mmol/L lactate solution during baseline and follow-up periods.

SETTING

Four Spanish nephrology centers.

PATIENTS

Thirty-one (20 Bic/Lac, 11 Lac) well-dialyzed (creatinine clearance > 55 L/week/1.73 m2 body surface area) CAPD patients.

INTERVENTIONS

Blood samples were taken for biochemistry tests at all visits. A physical examination was completed at baseline and month 3, and a medical update was completed after 1, 2, and 3 months, and at the follow-up visit. Adverse-event monitoring and notation of prescription changes were carried out continuously.

MAIN OUTCOME MEASURE

Effect on venous plasma bicarbonate level.

RESULTS

Venous plasma bicarbonate rose by 3.1 mmol/L (confidence intervals 1.6-4.8),from a baseline level of 23.0 mmol/L during the treatment period in those patients treated with Bic/Lac (p < 0.05 vs Lac). The number of acidotic patients (venous plasma bicarbonate < 24 mmol/L) was statistically significantly reduced at every treatment period visit in the Bic/Lac group (p < 0.05). There were no adverse findings with respect to vital signs, physical examination, or clinical symptoms, apart from one death in the control group.

CONCLUSIONS

The new Bic/Lac solution allowed better correction of acid-base status than the lactate solution.

[Intrathyroidal lymphocytes in autoimmune thyroid diseases]

Aiming to assess the autoimmune origin of certain thyroid diseases, we studied the phenotypic composition and the ability of intrathyroidal lymphocytes to a re-induce HLA-DR expression on autologous thyrocytes coming from patients with graves's disease, nodular goiter and papillary thyroid carcinoma. Lymphocytes coming only from graves's disease patients were capable of reinduce HLA-DR expression on autologous thyrocytes (24.1 +/- 13.6 vs 1.5 +/- 2.54% in nodular goiter and carcinoma), as interferon gamma did (17.4 +/- 8.34%). Phenotypic characterization showed a significant decrease of T-CD3 (total lymphocytes) and T-CD4 (helper) in lymphocytes coming from patients with nodular goiter and carcinoma, and a marked reduction of T-CD8 (suppressor) in lymphocytes coming from patients with graves disease. Thus the T-CD4/T-CD8 ratio varies according to the etiology of the thyroidal disease. The lack of suppressor activity would explain why cells coming only from patients with graves disease, show marked HLA-DR expression. These findings give little support to the autoimmune origin hypothesis for nodular goiter and thyroid carcinoma.

[Rapidly progressive kidney failure associated with neutrophil anticytoplasmic autoantibodies. Anatomo-clinical case]

We report a 63 year old woman with a rapidly progressive renal failure and fever of unknown origin. Laboratory tests showed anemia, increased ESR and a urine analysis compatible with a glomerular disease. Antineutrophil cytoplasmic autoantibodies were positive with a perinuclear pattern. Kidney biopsy showed an autoimmune crescenteric glomerulonephritis. The patient had a bad evolution, dying after a massive hemoptysis. The necropsy showed a disseminated arteritis without compromise of bronchial vessels. The oligosymptomatic presentation of this patient, bearing in mind the anatomo-pathological findings, is noteworthy and emphasizes the usefulness of serological markers as antineutrophil cytoplasmic autoantibodies in the differential diagnosis.

[Immunologic study of lymphoproliferative diseases]

Thirty six patients with stage IV lymphoproliferative diseases, were studied with a panel of monoclonal antibodies. There were 26 B-Lymphoproliferative Diseases (BLD): 11 B-chronic lymphocytic leukemia, 15 B-cell non Hodgkin lymphoma and 10 T-Lymphoproliferative Diseases (TLD): 4 T-cell non Hodgkin lymphoma, 4 adult T-cell leukemia/lymphoma, 1 T-chronic lymphocytic leukemia and 1 Sezary Syndrome. HLA-DR and CD 19 (B4) were the most common antigens found in BLD. CD4 + CD8 was the most common phenotype in TLD. 13 out of 26 BLD and 1 out of 10 TLD, patient were alive at the end of a 4 year observation period. Our study shows that immunophenotyping is a very useful diagnostic test in lymphoproliferative diseases. Along with cytology and histopathology, it can better define different pathologic groups and lead more specific treatments.