ESPE Abstracts

Introduction: Recent studies point to the existence of androgen-responsive non-coding (nc) RNAs in peripheral blood mononuclear cells (PBMC) RNA.

Aim: To quantify the androgen-responsive gene expression of SNORD5 and RNY5 and investigate their relationship to the testosterone (T) rise following hCG stimulation in boys with no genetic evidence of androgen insensitivity.

Methods: 19 boys with suspected DSD who were evaluated at RHC, Glasgow from 2018 to 2021 were included. Information on clinical, biochemical, and genetic assessment was obtained from clinical records. Of the 19 boys, 18 had undergone AR analysis to date and excluded AR variants. PBMC RNA was collected before and after hCG stimulation of the testes on day 4 (D4) and day 22 (D22), where appropriate, and gene expression was quantified using QuantStudioTM 3D Digital PCR.

Results: A median age at the time of hCG stimulation test was 0.8 yrs (0.5, 4). The median baseline and peak T levels were 0.5 nmol/l (0.5, 6.8) and 14.2 nmol/l (1.2,42.1), respectively. The median AMH was 752 pmol/l (13, 1588). Within this group, there was one patient who did not show a T response to hCG at all on D4 and a minimal response on D22 (1.2 nmol/l). The median fold change in SNORD5 and RNY5 on D4 in this patient was 0.09 and 0.05, respectively. The median fold change for the two ncRNAs on D22 was 0.14 and 0.04, respectively. In the rest of the cohort, the median post-hCG T on D4 and D22 was 13.6 nmol/l (2.5, 42.1) and 24.3 nmol/l (11.6, 37.3), respectively. In this group, the median fold change in SNORD5 expression on D4 and D22 was 1.93 (0.08, 13.9) and 1.4 (0.09,5.6), respectively. The median fold change in RNY5 expression on D4 and D22 was 0.8 (0.1, 37.5) and 0.7 (0.3, 7.7), respectively. Of the 19 boys, there were 3 boys who had a fold change in both ncRNAs that was below 25th centile at T peak. Of these 3, 1 was the aforementioned non-responder and the remaining 2 boys, although having a normal T response to hCG, also had variants in the CYP11B1 or HSD3B2 genes.

Conclusions: Expression levels of RNY5 and SNORD5 can be accurately quantified and show androgen dependency. Further research in poor hCG responders and genetically confirmed causes of DSD including androgen insensitivity is required to determine the diagnostic role of non-coding RNAs in XY DSD.