Profile of children with movement disorders (metabolic and genetic causes): single center study

OBJECTIVE: To determine the metabolic and genetic causes among children presenting with movement disorders in single center study over a period of 20 years. METHODS: we retrospectively reviewed the medical records of 135 patients presenting to the outpatient pediatric neurology clinic, Dhahran, Saudi Arabia with different types of movement disorders between 1999-2019. We reviewed clinical features, neuroimaging and biochemical investigations. The genetic testing is done at Bioscientia diagnostics (Germany). The types of genetic testing requested are; either targeted gene test, NGS gene panel, or whole exome sequencing (WES). RESULTS: 55 children (40%), found to have genetic and metabolic causes for their movement disorder . Ataxia in 15 patients with different mutations, like VLDR, GEM1N4, DARS2, WWOX, SACS, KIF1A, and COQ8A in twins. 7 patients with Joubert syndrome and ataxia. 8 cases Neuronal Ceroid Lipofusinosis (NCL). 7 cases with Glutaric aciduria type1. 4 cases with organic acidemias and 3 Non-Ketotic Hyperglycinemia. 5 cases with Parkinsonism (PLA2G6, ATP13A2, SLC6A3,and 2 sibs with SLC18A2 mutations. Mitochondrial diseases 6 cases ( 2 Leigh disease LRPPRC, PET100, POLG ). Rett syndrome 4 cases and 2 patients with Angelman syndrome. One boy with early -onset torsion dystonia(DYT1 gene.

CONCLUSIONS: due to high prevalence of consanguineous marriage in Arabia, movement disorders due to genetic and metabolic diseases are common and now possible to be diagnosed early due to availability of genetic testing. (i.e., chromosomal microarray, NGS panels, WES). So early management with special diets, vitamins and cofactor supplementation can cure or alter the prognosis of metabolic diseases.
Keywords: pediatric movement disorders