Developmental delay with impairment of verbal and non-verbal cognitive skills was also documented at follow-up of cblF patients despite treatment (Alfadhel et al 2011; Gailus et al 2010), but in some early treated patients, neurocognitive outcome was satisfactory (Miousse et al 2011; Armour et al 2013). This evidence concerns the gene LMBRD1 and Global developmental delay.