The function of CDKL5 (cyclin dependent kinase like 5, Ensembl gene identifier ENSG00000008086) is as follows. Mediates phosphorylation of MECP2 (PubMed:15917271, PubMed:16935860). May regulate ciliogenesis (PubMed:29420175). {ECO:0000269|PubMed:15917271, ECO:0000269|PubMed:16935860, ECO:0000269|PubMed:29420175}.