The p190 RhoGAPs, ARHGAP35, and ARHGAP5 are implicated in GnRH neuronal development: Evidence from patients with idiopathic hypogonadotropic hypogonadism, zebrafish, and in vitro GAP activity assay

Margaret F. Lippincott*, Wanxue Xu, Abigail A. Smith, Xinyu Miao, Agathe Lafont, Omar Shennib, Gordon J. Farley, Riwa Sabbagh, Angela Delaney, Maria Stamou, Lacey Plummer, Kathryn Salnikov, Neoklis A. Georgopoulos, Veronica Mericq, Richard Quinton, Frederic Tran Mau-Them, Sophie Nambot, Asma Hamad, Helen Brittain, Rebecca S. ToozeEduardo Calpena, Andrew O.M. Wilkie, Marjolaine Willems, William F. Crowley, Ravikumar Balasubramanian, Nathalie Lamarche-Vane, Erica E. Davis, Stephanie B. Seminara

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Purpose: The study aimed to identify novel genes for idiopathic hypogonadotropic hypogonadism (IHH). Methods: A cohort of 1387 probands with IHH underwent exome sequencing and de novo, familial, and cohort-wide investigations. Functional studies were performed on 2 p190 Rho GTPase–activating proteins (p190 RhoGAP), ARHGAP35 and ARHGAP5, which involved in vivo modeling in larval zebrafish and an in vitro p190A-GAP activity assay. Results: Rare protein-truncating variants (PTVs; n = 5) and missense variants in the RhoGAP domain (n = 7) in ARHGAP35 were identified in IHH cases (rare variant enrichment: PTV [unadjusted P = 3.1E-06] and missense [adjusted P = 4.9E-03] vs controls). Zebrafish modeling using gnrh3:egfp phenotype assessment showed that mutant larvae with deficient arhgap35a, the predominant ARHGAP35 paralog in the zebrafish brain, display decreased GnRH3-GFP+ neuronal area, a readout for IHH. In vitro GAP activity studies showed that 1 rare missense variant [ARHGAP35 p.(Arg1284Trp)] had decreased GAP activity. Rare PTVs (n = 2) also were discovered in ARHGAP5, a paralog of ARHGAP35; however, arhgap5 zebrafish mutants did not display significant GnRH3-GFP+ abnormalities. Conclusion: This study identified ARHGAP35 as a new autosomal dominant genetic driver for IHH and ARHGAP5 as a candidate gene for IHH. These observations suggest a novel role for the p190 RhoGAP proteins in GnRH neuronal development and integrity.

Original languageEnglish (US)
Pages (from-to)2501-2515
Number of pages15
JournalGenetics in Medicine
Volume24
Issue number12
DOIs
StatePublished - Dec 2022

Keywords

  • Developmental disorder
  • Idiopathic hypogonadotropic hypogonadism
  • Intellectual disability
  • Puberty
  • Rho GTPase–activating protein

ASJC Scopus subject areas

  • Genetics(clinical)

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