Global developmental delay and intellectual disability (GDD/ID) affect 3% of the paediatric population. Since its differential diagnosis is broad, community –based clinicians tend to order copper and ceruloplasmin tests to screen for Wilson’s and Menkes disease (mutations in ATP7A or ATP7B).
However, a recent study determined that neither Wilson’s nor Menkes disease have been identified using these tests in children with global developmental delay/intellectual disability.
In addition, false abnormal copper and ceruloplasmin results lead to an increase in the number of total referrals and unnecessary follow ups (4% in the above study). Children with Wilson’s disease are more likely to present with hepatic manifestations than neurologic symptoms, while those with Menkes disease show multiple abnormalities including developmental delay and epilepsy typically within the first 3 months of life.
Sources :
Shribman, S. et al. Clinical presentations of Wilson disease. Clinical presentations of Wilson disease. Ann Transl Med. 2019 Apr;7(Suppl 2):S60. PMID: 31179297.
Vairo, F.P.E. et al. A systematic review and evidence-based guideline for diagnosis and treatment of Menkes disease. Mol Genet Metab. 2019 Jan;126(1):6-13. PMID: 30594472.
Vallance, H. et al. Diagnostic yield from routine metabolic screening tests in evaluation of global developmental delay and intellectual disability. Paediatr Child Health. 2020 Dec 19;26(6):344-348. PMID: 34676012.