Genetic Diversity and Expanded Phenotypes in Dystonia: Insights from Large-Scale Exome Sequencing.

Dystonia is one of the most prevalent movement disorders, characterized by significant clinical and etiological heterogeneity. Despite considerable heritability (~25%) and the identification of several disease-linked genes, the etiology in most patients remains elusive. Moreover, understanding the correlations between clinical manifestation and genetic variants has become increasingly complex.

Uncovering the genetic basis of Parkinson's disease globally: from discoveries to the clinic.

Knowledge on the genetic basis of Parkinson's disease has grown tremendously since the discovery of the first monogenic form, caused by a mutation in α-synuclein, and with the subsequent identification of multiple other causative genes and associated loci. Genetic studies provide insights into the phenotypic heterogeneity and global distribution of Parkinson's disease. By shedding light on the underlying biological mechanisms, genetics facilitates the identification of new biomarkers and therapeutic targets.

Loss-of-Function Variant in the SMPD1 Gene in Progressive Supranuclear Palsy-Richardson Syndrome Patients of Chinese Ancestry.

Lysosomal dysfunction plays an important role in neurodegenerative diseases, including Parkinson's disease (PD) and possibly Parkinson-plus syndromes such as progressive supranuclear palsy (PSP). This role is exemplified by the involvement of variants in the GBA1 gene, which results in a deficiency of the lysosomal enzyme glucocerebrosidase and is the most frequently identified genetic factor underlying PD worldwide. Pathogenic variants in the SMPD1 gene are a recessive cause of Niemann-Pick disease types A and B.

New insights from a multi-ethnic Asian progressive supranuclear palsy cohort.

Background: Progressive supranuclear palsy (PSP) is a rare, disabling, neurodegenerative disease, with few studies done in Asian populations.

Methods: We prospectively characterized the clinical features and disease burden in a consecutively-recruited multi-ethnic Asian PSP cohort. Patients were extensively phenotyped using the Movement Disorder Society (MDS-PSP) clinical diagnostic criteria and the PSP-Clinical Deficits Scale (PSP-CDS).

A KMT2B Frameshift Variant Causing Focal Dystonia Restricted to the Oromandibular Region After Long-Term Follow-up.

KMT2B-linked dystonia (DYT-KMT2B) is a childhood-onset dystonia syndrome typically beginning in the lower limbs and progressing caudocranially to affect the upper limbs with eventual prominent craniocervical involvement. Despite its recent recognition, it now appears to be one of the more common monogenic causes of dystonia syndromes. Here, we present an atypical case of DYT-KMT2B with oromandibular dystonia as the presenting feature, which remained restricted to this region three decades after symptom onset.

Glucocerebrosidase (GBA) gene variants in a multi-ethnic Asian cohort with Parkinson's disease: mutational spectrum and clinical features.

GBA variants are associated with increased risk and earlier onset of Parkinson's disease (PD), and more rapid disease progression especially with "severe" variants typified by p.L483P. GBA mutation screening studies from South-East Asia, with > 650 million inhabitants of diverse ancestries, are very limited.

PINK1 p.Leu347Pro mutations in Malays: Prevalence and illustrative cases.

Background: An improved understanding of the genetic determinants of Parkinson's disease (PD) in underrepresented populations, and better characterization of genotype-phenotype correlations in monogenic PD, are needed. Scarce literature exists regarding the genetic aetiology of PD in Malays, who comprise 200 million individuals in South-East Asia. Phenotypic data regarding PARK-PINK1 are also limited.

Clinical Phenotype of LRRK2 R1441C in 2 Chinese Sisters.

Pathogenic and risk variants in the LRRK2 gene are among the main genetic contributors to Parkinson's disease (PD) worldwide, and LRRK2-targeted therapies for patients with PARK-LRRK2are now entering clinical trials. However, in contrast to the LRRK2 G2019S mutation commonly found in Caucasians, North-African Arabs, and Ashkenazi Jews, relatively little is known about other causative LRRK2 mutations, and data on genotype-phenotype correlations are largely lacking. This report is from an ongoing multicentre study in which next-generation sequencing-based PD gene panel testing has so far been conducted on 499 PD patients of various ethnicities from Malaysia.