Two unrelated Brazilian girls with sporadic CPP (Patients 4 and 5) carried a heterozygous indel insertion of 9 bp in exon 1 (c.15_23dup) of MECP2, corresponding to the N-terminal domain of the protein (p.Ala6_Ala8dup) (19). The gene discussed is MECP2; the disease is central precocious puberty.