We have achieved some improvement in neonatal MD detection by performing targeted DNA sequencing (frequently post mortem) in cases of neonates with lactic aciduria (LA-uria) found in selective GC–MS screening, including over 90 % of SCO2 [14] and DGUOK [15] deficiencies, and ~ 50 % of SURF1 deficiency [16]. Here, SCO2 is linked to Menkes disease.