Genetic testing in paediatric neurological disorders

To evaluate genetic testing practices (exome sequencing, commercial panel, and in-house genetic panels) from a large tertiary hospital for determining gaps, and to identify clinical associations with pathogenic genetic variants.

This retrospective cohort study included patients (age < 18 years) from a neurology department for whom genetic testing was requested for neurological disorders, epilepsy, and movement disorders (2020-2023). Logistic regression was used to identify clinical features predictive of positive results. The clinical benefits of genetic testing were studied.

Three hundred and ninety patients underwent genetic testing by exome sequencing (n = 125), commercial panel (n = 143), in-house epilepsy (n = 78), and movement disorder (n = 44) gene panels. Exome sequencing had the highest pathogenic yield (n = 49, 39%), followed by epilepsy (n = 22, 28%), movement disorder (n = 11, 25%), and commercial (n = 22, 15%) panels. Variants of uncertain significance were highest in commercial (64%) and epilepsy (34%) panels. Among the exome sequencing cohort, the predominant clinical features were developmental delay (89%), intellectual disability (51%), and epilepsy (35%). Pathogenic variants in the exome sequencing cohort were more likely in patients with severe developmental delay (33%, p = 0.03) and hypotonia (39%, p = 0.05). There was significant utility of genetic testing in informing clinical decision making (49% of pathogenic variants in exome sequencing cohort).

Exome sequencing outperforms gene panels in confirming genetic diagnoses in paediatric neurological disorders, and highlights the need for building local diagnostic genetic-testing resources.