Endocrine Abstracts

The gene NR5A1, which encodes steroidogenic factor 1 (SF-1), is a pivotal transcriptional regulator of genes involved in adrenal and gonadal function, including several steroidogenic enzymes and key genes necessary for male sex determination and differentiation, testicular descent and reproduction (such as SOX9, AMH, INSL3, and AR). The most severe phenotypes associated with NR5A1 mutations include gonadal dysgenesis, disorders of sex development (DSD) and adrenal insuf...

Klinefelter syndrome (KS) was first described in 1942 and the cause for the syndrome was identified as a supernumerary X chromosome resulting in the karyotype 47,XXY. 80–90% of KS cases bear this karyotype, whereas the remaining exhibit (in decreasing frequency) varying mosaicism (e.g. 47,XXY/46,XY), carry additional sex chromosomes (48,XXXY; 48,XXYY; 49,XXXXY) or structurally abnormal X chromosomes. The prevalence of KS is up to 1 in 500 boys, and it is the most common c...