ZBTB20 mutations cause GnRH deficiency by impairing the neurogenesis in the subventricular zone

Background: Congenital hypogonadotropic hypogonadism (CHH) is caused by defective GnRH neuron development, yet nearly 50% of cases lack a genetic diagnosis, severely limiting clinical management. Since olfactory bulb (OB) malformations can disrupt GnRH neuron migration, we investigated whether impaired subventricular zone (SVZ) neurogenesis - critical for OB development - contributes to CHH pathogenesis. Methods: Leveraging our 15-year effort in building one of Asia’s largest CHH cohort (812 unrelated patients, 49 families), we identified a pathogenic ZBTB20 mutation (p.R300C) in a four-generation CHH family with 7 affected members that presents a unique opportunity to study disease mechanisms. We generated nervous system-specific Zbtb20 conditional knockout mice (cKO) to assess phenotypic and mechanistic consequences. Molecular analyses, including transcriptional regulation assays, were performed to explore downstream pathways. Findings: Four additional heterozygous ZBTB20 variants were detected in the CHH cohort. Zbtb20 cKO mice exhibited hallmark CHH features: GnRH neuron deficiency, hypogonadism, and infertility. Mechanistically, Zbtb20 deficiency impaired SVZ NSCs proliferation and disrupted their migration via the rostral migratory stream (RMS) to the OB. We identified Thbs4 as a key downstream target, as ZBTB20 transcriptionally activates Thbs4, which is critical for SVZ NSCs migration. Interpretation: Our study establishes ZBTB20 as a novel CHH-associated gene and demonstrates its essential role in SVZ-OB neurogenesis. Loss of ZBTB20 function leads to OB atrophy, GnRH deficiency, and CHH pathogenesis, uncovering a previously unrecognized link between SVZ NSCs dysregulation and reproductive neuroendocrine dysfunction.