Hypogonadism is a condition in which the testes or ovaries produce little or no sex hormones. Hypogonadotropic hypogonadism is a type of hypogonadism that is caused by problems with the pituitary gland or hypothalamus. Affected individuals typically present with puberty delayed beyond the age of 18 with low or inappropriately normal luteinising hormone (LH) and follicle stimulating hormone (FSH) levels. There is an identifiable genetic cause for 50%–60% of cases.

Prader-Willi syndrome is a genomic imprinting disorder that typically presents neonatally with central hypotonia, poor feeding and failure to thrive. In childhood, patients typically present with hyperphagia, obesity and intellectual disability.