MOLECULAR GENETICS OF ADRENAL HYPOPLASIA CONGENITA

Insight into the molecular pathogenesis of adrenal hypoplasia congenital (AHC) requires an understanding of the complexity of this ‘‘simple’’ Mendelian disorder. We will explore the investigation of this complexity in vitro and in model organisms. Complex biological systems have the characteristic architecture of scale-free networks, which gives them extremely robust properties. We have developed a high density-multiplex reverse transcriptase-polymerase chain reaction (HD-MRT-PCR) approach that permits HD-MRT for more than 20 transcripts in a single-tube reaction, followed by PCR amplification. Our results compare adrenal cortical cell lines and confirm that NCI-H295 cells are the optimal model for investigation of the transcriptional regulatory network involved in adrenal development. We also show that mutation in a critical network component like DAX1 compromises not a single pathway, but an entire network sector. We will examine very early preliminary evidence from lines of transgenic mice that express green fluorescent protein (GFP) under control of the DAX1 promoter. These mice express GFP in the hypothalamus and adrenal cortex in a pattern anticipated by DAX1 expression studies. These mice will serve as a model for investigation of adrenal development. We will also present our preliminary approach to identify genes involved in adrenal development using a vertebrate model organism, zebrafish. Our investigations are developing an understanding of the complex regulatory networks involved in normal adrenal development and AHC pathogenesis.