Genetic characterisation of 22q11.2 variations and prevalence in patients with congenital heart disease

ObjectivesThe 22q11.2 deletion syndrome is considered the most frequent chromosomal microdeletion syndrome in humans and the second leading chromosomal cause of congenital heart disease (CHD). We aimed to identify the prevalence and the detailed genetic characterisation of 22q11.2 region in children with CHD including simple defects and to explore the genotype-phenotype relationship between deletion/amplification type and clinical data.MethodsPatients with CHD for surgery were screened by multiplex ligation-dependent probe amplification and capillary electrophoresis methods. Universal Probe Library technology was applied for validation.ResultsIn 354 patients with CHD, 40 (11.3%) carried different levels of deletions/amplifications at the 22q11.2 region with various phenotypes. The affected genes at this region include CDC45 (15 patients), TBX1 (8), USP18 (8), RTDR1 (7), SNAP29 (6), TOP3B (6), ZNF74 (4) and other genes with less frequency. Among those, two patients carried 3 Mb typically deleted region from CLTCL1 to LZTR1 (low copy repeats A–D) or 1.5 Mb deletions from CLTCL1 to MED15 (low copy repeats A–C). Clinical facial manifestations were found in 12 patients.ConclusionsThis study revealed an unexpected high prevalence of chromosome 22q11.2 variations in patients with CHD even in simple defects. The genotype-phenotype relationship analysis suggests that genetic detection of 22q11.2 may become necessary in all patients with CHD and that detection of unique deletions or amplifications may provide useful insight into personalised management in patients with CHD.

Abstract 280: Modulation of Aldosterone Synthesis in Human Adrenocortical Cells by Estrogens via an Interaction on Beta Estrogen and Gpr30 Receptor Subtypes

Background and aim. The gender dimorphism in the pressor effect of hyperaldosteronism suggests that estrogens may modulate aldosterone synthesis. Estrogens were suggested to affect adrenocortical cell proliferation via beta estrogen receptor (ERβ), but it remains unknown if they also influence aldosterone synthesis. Methods. We therefore investigated the expression of alpha (ERα), ERβ and of G protein-coupled receptor (GPR)30 in HAC15 cells, a human adrenocortical carcinoma cell line. HAC15 cells were stimulated with 10 -7 M 17β-estradiol (E2) alone, or with a selective ERβ antagonist (10 -5 M; Tetrahydrochrysenediol THC), a selective ERα antagonist (10 -5 M; MPP dihydrochloride), a non selective ERα and ERβ antagonist (10 -5 M; ICI 182.780 fulvestrant), a selective GPR30 receptor antagonist (10 -5 M; G-15). The cells were also exposed to the highly selective GPR30 agonist G-1, alone or in the presence of MPP, or THC, or Fulvestrant and G-15. CYP11B2 mRNA expression was measured with quantitative real time RT-PCR (Universal Probe Library Roche). Results. The three estrogen receptor subtypes were found to be expressed at different levels (ERβ>>ERα=GPR30) in HAC15 cells. E2 alone or on top of selective ERα antagonism did not alter CYP11B2 expression. At variance, E2 on top of selective ERβ antagonism, or of combined ERβ and ERα antagonism, caused a 5- to 7- fold upregulation of CYP11B2 mRNA, a finding that was replicated by the exposure of cells to G-1 on top of combined ERβ and ERα blockade. Conclusions . 1) GPR30 is expressed in human adrenocortical cells at levels that are comparable to ERα, but less abundatly than ERβ subtype receptor. 2) 17β-estradiol activates CYP11B2 synthesis via an interaction between ERβ blockade and GPR30 activation. Hence, by showing a role for estrogens in the regulation of aldosterone synthesis via GPR30 subtype receptor, these results could account for the diverse pressor effects of excess aldosterone in men and in fertile vs post-menopausal women.