X-Chromosome Association Study in Latin American Cohorts Identifies New Loci in Parkinson's Disease.

BACKGROUND: Sex differences in Parkinson's disease (PD) risk are well-known. However, the role of sex chromosomes in the development and progression of PD is still unclear. OBJECTIVE: The objective of this study was to perform the first X-chromosome-wide association study for PD risk in a Latin American cohort. METHODS: We used data from three admixed cohorts: (1) Latin American Research consortium on the Genetics of Parkinson's Disease (n = 1504) as discover cohort, and (2) Latino cohort from International Parkinson Disease Genomics Consortium (n = 155) and (3) Bambui Aging cohort (n = 1442) as replication cohorts. We also developed an X-chromosome framework specifically designed for admixed populations. RESULTS: We identified eight linkage disequilibrium regions associated with PD. We replicated one of these regions (top variant rs525496; discovery odds ratio [95% confidence interval]: 0.60 [0.478-0.77], P = 3.13 × 10-5 replication odds ratio: 0.60 [0.37-0.98], P = 0.04). rs5525496 is associated with multiple expression quantitative trait loci in brain and non-brain tissues, including RAB9B, H2BFM, TSMB15B, and GLRA4, but colocalization analysis suggests that rs5525496 may not mediate risk by expression of these genes. We also replicated a previous X-chromosome-wide association study finding (rs28602900), showing that this variant is associated with PD in non-European populations. CONCLUSIONS: Our results reinforce the importance of including X-chromosome and diverse populations in genetic studies. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Pregnancy in patients with Sydenham's Chorea.

BACKGROUND: Sydenham's Chorea is a frequent cause of chorea during pregnancy, chorea gravidarum. The aim of this article is to describe the effect of pregnancy in a consecutive series of patients with diagnosis of Sydenham's Chorea. METHODS: A chart review was performed of all patients with the diagnosis of Sydenham's Chorea followed up at our institution from 07/1993 through 08/2010 and who became pregnant. RESULTS: From 66 patients, 20 became pregnant. Of these 20 patients, 15 (75%) developed chorea gravidarum. Generalized chorea was found in 67% of these 15 patients, focal or multifocal chorea was identified in 20% and 13.4% developed hemichorea. In 80% of cases chorea began in the first 6 months of gestation. Three women with previous persistent chorea experienced worsening of the movement disorder during pregnancy. Remission occurred after delivery in 11 patients whereas the other four remained with non-disabling chorea during the first 12 months after delivery. Abortion occurred in two patients (13%). All patients with chorea gravidarum subsequently treated with oral contraceptives developed recurrence of chorea. CONCLUSIONS: Chorea gravidarum is a frequent complication of pregnancy in patients with previous history of Sydenham's Chorea and an increased risk of miscarriage should be considered. Our findings confirm the notion that chorea gravidarum results from hormonal changes acting on previously dysfunctional basal ganglia.