[Significance of whole exome sequencing in the diagnostics of rare neurological diseases - own experiences through a case presenting with ataxia].

Next generation sequencing (NGS) technologies reshape the diagnostics of rare neurological diseases. In the background of certain neurological symptoms, such as ataxia, many acquired and genetic causes may be present. Variations in a given gene can present with variable phenotypes, too. Because of this phenomenon, the conventional one gene sequencing approach often fails to identify the genetic background of a disease. Next generation sequencing panels allow to sequence 50-100 genes simultaneously, and if the disease stratification is not possible based on the clinical symptoms, whole exome sequencing can help in the diagnostic of genetic disorders with atypical presentation. This case study is about the exome sequencing of a patient with cerebellar ataxia. Genetic investigations identified rare variants in the SPG11 gene in association with the clinical phenotype, which gene was originally described in the background of hereditary spastic paraparesis. Our article highlights that in certain cases the variability of the leading presenting symptom makes it hard to select the correct gene panel. In our case the variants in the gene, formerly associated to hereditary spastic paraparesis, resulted in cerebellar ataxia initially, so even an ataxia NGS gene panel would not detect those. Orv Hetil. 2018; 159(28): 1163-1169.