• Delanie B Macedo, Monica M França, Luciana R Montenegro, Marina Cunha-Silva, Danielle S Best, Ana Paula Abreu, Ursula B Kaiser, Berenice B Mendonca, Alexander A L Jorge, Vinicius N Brito, and Ana Claudia Latronico.
• Unidade de Endocrinologia do Desenvolvimento, Laboratório de Hormônios e Genética Molecular/LIM42, Hospital das Clínicas, Disciplina de Endocrinologia, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
• Neuroendocrinology. 2018 Jan 1; 107 (2): 127-132.

ContextLoss-of-function mutations in the coding region of MKRN3, a maternally imprinted gene at chromosome 15q11.2, are a common cause of familial central precocious puberty (CPP). Whether MKRN3 alterations in regulatory regions can cause CPP has not been explored to date. We aimed to investigate potential pathogenic variants in the promoter region of MKRN3 in patients with idiopathic CPP.Patients/MethodsA cohort of 110 patients with idiopathic CPP was studied. Family history of precocious sexual development was present in 25%. Mutations in the coding region of MKRN3 were excluded in all patients. Genomic DNA was extracted from peripheral blood leukocytes, and 1,100 nucleotides (nt) of the 5'-regulatory region of MKRN3 were amplified and sequenced. Luciferase assays were performed in GT1-7 cells transiently transfected with plasmids containing mutated and wild-type MKRN3 promoter.ResultsWe identified a rare heterozygous 4-nt deletion (c.-150_-147delTCAG; -38 to -41 nt upstream to the transcription start site) in the proximal promoter region of MKRN3 in a girl with CPP. In silico analysis predicted that this deletion would lead to the loss of a binding site for a downstream res-ponsive element antagonist modulator (DREAM), a potential transcription factor for MKRN3 and GNRH1 expression. Luciferase assays demonstrated a significant reduction of MKRN3 promoter activity in transfected cells with a c.-150_- 147delTCAG construct plasmid in both homozygous and heterozygous states when compared with cells transfected with the corresponding wild-type MKRN3 promoter region.ConclusionA rare genetic alteration in the regulatory region of MKRN3 causes CPP.© 2018 S. Karger AG, Basel.

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