Should children with cerebral palsy and normal imaging undergo testing for inherited metabolic disorders?

AIM: For the 9% to 16% of children with cerebral palsy (CP) who have normal brain imaging, further testing for metabolic and/or genetic conditions has been recommended. This study aimed to identify a cohort of children with CP with normal magnetic resonance imaging (MRI), clinically review and describe the cases, and assess the value of testing for inherited metabolic disorders in these children.
METHOD: Children with congenital CP born from 1999 to 2005 were selected from a population register. Normal MRI reports were identified and the scans reassessed. Children whose scans were performed before 18 months were excluded, as were children with spastic CP (Gross Motor Function Classification System [GMFCS] level I). The remainder were reviewed clinically and offered investigations.
RESULTS: Of 730 children identified, 515 had available imaging and 54 were confirmed as normal. Cases with non-spastic CP and those with milder clinical severity were more likely to have normal imaging. Twenty-three children (17 males, six females; mean age 6 y 11 mo, SD 1 y 10 mo, range 3 y 0 mo to 10 y 0 mo) were reviewed clinically and offered investigations. Twelve children had spasticity (11 with diplegia, one quadriplegia), three had dyskinesia, five ataxia, and three hypotonia. Two children functioned in GMFCS level I, 11 in level II, seven in level III and three in level IV. Four children with spasticity had unusual features. No alternative diagnoses were made.
INTERPRETATION: Although important to consider in individual cases, comprehensive metabolic testing failed to clarify the aetiology of CP further in this large cohort of children with normal MRIs, even those with atypical features.