There is experimental evidence that a portion of follicle-stimulating hormone (FSH) secretion is independent of hypothalamic influences. A 29 year old woman with familial pure gonadal dysgenesis developed myelodysplastic syndrome. Endocrine investigations showed discrepancy between serum FSH and luteinizing hormone (LH) levels. FSH levels remained elevated while LH levels decreased. The FSH to LH ratio was 10 (normal 2-2.5). The fall in LH is likely to be due to factor(s) involved directly and specifically in LH synthesis and release. Exogenous LH releasing hormone administration as well as hormonal replacement treatment increased LH levels. The FSH to LH ratio decreased to 7. This case supports the hypothesis of differential regulation of FSH and LH, and that FSH secretion is at least partly autonomous.