The Genetic Architecture of Parkinson Disease in Spain: Characterizing Population-Specific Risk, Differential Haplotype Structures, and Providing Etiologic Insight

The American Genome Center, on behalf of the International Parkinson Disease Genomics Consortium

Research output: Contribution to journalArticle

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Abstract

Background: The Iberian Peninsula stands out as having variable levels of population admixture and isolation, making Spain an interesting setting for studying the genetic architecture of neurodegenerative diseases. Objectives: To perform the largest PD genome-wide association study restricted to a single country. Methods: We performed a GWAS for both risk of PD and age at onset in 7,849 Spanish individuals. Further analyses included population-specific risk haplotype assessments, polygenic risk scoring through machine learning, Mendelian randomization of expression, and methylation data to gain insight into disease-associated loci, heritability estimates, genetic correlations, and burden analyses. Results: We identified a novel population-specific genome-wide association study signal at PARK2 associated with age at onset, which was likely dependent on the c.155delA mutation. We replicated four genome-wide independent signals associated with PD risk, including SNCA, LRRK2, KANSL1/MAPT, and HLA-DQB1. A significant trend for smaller risk haplotypes at known loci was found compared to similar studies of non-Spanish origin. Seventeen PD-related genes showed functional consequence by two-sample Mendelian randomization in expression and methylation data sets. Long runs of homozygosity at 28 known genes/loci were found to be enriched in cases versus controls. Conclusions: Our data demonstrate the utility of the Spanish risk haplotype substructure for future fine-mapping efforts, showing how leveraging unique and diverse population histories can benefit genetic studies of complex diseases. The present study points to PARK2 as a major hallmark of PD etiology in Spain.

Original languageEnglish (US)
Pages (from-to)1851-1863
Number of pages13
JournalMovement Disorders
Volume34
Issue number12
DOIs
StatePublished - Dec 1 2019

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Keywords

  • Parkinson's disease
  • Spanish population
  • age at onset
  • polygenic risk score
  • risk haplotype

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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