👤 Christoph Hotzy

Early-onset dementia (EOD), with symptom onset before age 65, has a strong genetic burden. Due to genetic and clinical overlaps between different types of dementia, whole-exome sequencing (WES) has emerged as an appropriate screening method for diagnostic testing and novel gene-finding approaches. We performed WES and C9orf72 repeat testing in 60 well-defined Austrian EOD patients. Seven patients (12%) carried likely disease-causing variants in monogenic genes, PSEN1, MAPT, APP, and GRN. Five patients (8%) were APOE4 homozygote carriers. Definite and possible risk variants were detected in the genes TREM2, SORL1, ABCA7 and TBK1. In an explorative approach, we cross-checked rare gene variants in our cohort with a curated neurodegeneration candidate gene list and identified DCTN1, MAPK8IP3, LRRK2, VPS13C and BACE1 as promising candidate genes. Conclusively, 12 cases (20%) carried variants relevant to patient counseling, comparable to previously reported studies, and can thus be considered genetically resolved. Reduced penetrance, oligogenic inheritance and not yet identified high-risk genes might explain the high number of unresolved cases. To address this issue, we provide complete genetic and phenotypic information (uploaded to the European Genome-phenome Archive), enabling other researchers to cross-check variants. Thereby, we hope to increase the chance of independently finding the same gene/variant-hit in other well-defined EOD patient cohorts, thus confirming new genetic risk variants or variant combinations. Show less

A clinical overlap between Parkinson's disease (PD) and essential tremor (ET) has prompted a discussion whether these conditions share common genetic susceptibility factors. Recently, the first genome-wide association study in ET revealed a significant association with a variant in the LINGO1 gene. LINGO1 has also been demonstrated to play a role in the survival of dopaminergic neurons in an animal model of PD, and therefore constitutes a potential candidate gene for PD. In this study, SNPs rs9652490, rs11856808, and rs7177008 of LINGO1 were genotyped in a total of 694 Austrian subjects (349 PD, 345 controls). No association could be found between genotype or allele counts and PD. Neither did a subgroup analysis in tremor-dominant patients with PD reveal a significant association. This study on LINGO1-variants in PD argues against a major role of LINGO1 gene variations for PD. Show less

We identified a marker in LINGO1 showing genome-wide significant association (P = 1.2 x 10(-9), odds ratio = 1.55) with essential tremor. LINGO1 has potent, negative regulatory influences on neuronal survival and is also important in regulating both central-nervous-system axon regeneration and oligodendrocyte maturation. Increased axon integrity observed in Lingo1 mouse [corrected] knockout models highlights the potential role of LINGO1 in the pathophysiology of ET [corrected] Show less