Whole exome sequencing in patients negative for MC2R, MRAP and STAR mutations, identified mutations in minichromosome maintenance 4 MCM4, nicotinamide nucleotide transhydrogenase NNT, thioredoxin reductase 2 TXNRD2, cytochrome p450scc CYP11A1, and sphingosine 1-phosphate lyase SGPL1 accounting for a further 10% of FGD.
Previously, genetic defects in FGD have been identified in the ACTH receptor gene (MC2R), its accessory protein (MRAP) and the steroidogenic acute regulatory protein gene (STAR).
Currently, mutations in three genes: the ACTH receptor (MC2R); the melanocortin 2 receptor accessory protein (MRAP); and the steroidogenic acute regulatory protein (STAR) are known to give rise to FGD types 1-3.
Our results demonstrate that certain mutations in STAR (R192C and the previously reported R188C) can present with a phenotype indistinguishable from that seen in FGD.