SAT-202 DNA Methylation Changes in the GHR, IGF1R and INSR Genes in Foreskin from 46,XY DSD Children Born Adequate (AGA) or Small for Gestational Age (SGA)

Abstract Disclosure: L. Zoff: None. F.M. Garcia: None. G. Veneruzzo: None. G. Aschettino: None. M.C. Mattone: None. E.B. Berensztein: None. C. Terada: None. N. Perez Garrido: None. R.M. Marino: None. C. Alonso: None. G. Guercio: None. A. Belgorosky: None. M.S. Baquedano: None. Being born SGA in 46, XY DSD patients without molecular diagnosis and with no specific disorders of undermasculinization have a higher prevalence than expected for the general population. Numerous links have been made between infant growth restriction and specific epigenetic alterations, including changes in DNA methylation, thereby implicating such regulation in appropriate growth and development. Moreover, several studies have suggested that SGA children present with permanent alterations in the epigenome due to the programming of fetal tissues. The Growth hormone (GH)/ insulin-like growth factor type 1 (IGF1) and Insulin axis, crucial in human growth and development, is involved in adrenogonadal differentiation in mice. We hypothesized that epigenetic changes in the GH/IGFs and Insulin axis, could mediate the association between being born SGA and with DSD in humans. Our aim was to evaluate both the levels and patterns of methylation across the regulatory regions of GHR, IGF1R, and INSR genes in foreskin (FT) from 46,XY DSD children born either AGA (AGADSD-FT, n=7; 0.8-7.37y) or SGA (SGADSD-FT, n=7; 1.3-7.3y) vs age-matched control children (C-FT; n=7, 0.9-7y) using targeted deep-amplicon bisulfite sequencing on a MiSeq system. Sequencing libraries of 4 promoter CpG-rich regions for GHR, 3 for IGF1R and 5 for INSR (104, 103 and 141 CpG sites, respectively) were analyzed for mean methylation values of all CpG sites using amplikyzer2 software. The average CpG methylation levels of the SP1-responsive IGF1R proximal promoter [GRCh38:15:98648387: 98648592:1 (-152 to +53)] and the 5´UTR regulatory region [GRCh38:15:98649214: 98649496:1 (+676 to +958)] were significantly higher in SGADSD-FT than in C-FT and AGADSD-FT (Kruskal Wallis test, p<0.05). In locus-by-locus comparative analyses, higher methylation levels of CpG-23, CpG-17, CpG-15, CpG-13, and CpG-11 within the unique Sp1-dependent initiator motif of the IGF1R gene were detected in SGADSD-FT compared with C-FT and AGADSD-FT, p<0.05. The mean methylation levels of INSR promoter regions [GRCh38:19:7294796:7295022:-1 (-608 to -381) and GRCh38:19:7294410:7294702:1 (-288 to +5)], covering the binding site of activating transcription factors, were higher in DSD 46, XY patients, both in SGADSD-FT and in AGADSD-FT than in C-FT (p<0.05). There were no significant differences in GHR promoter methylation among the three FT groups. Promoter DNA methylation is a fundamental epigenetic mark associated with transcriptional repression during development. According to our findings, it could be speculated that epigenetic repression, mainly of IGF1R, might contribute to mediate the association between being born SGA and 46XYDSD in humans. Nevertheless, whether or not the epigenetic changes observed in postnatal foreskin are present at the time of sexual differentiation during intrauterine life must be determined. Presentation: Saturday, July 12, 2025