The Prader-Willi syndrome: neuroendocrine study of identical twins.

Identical twins with the Prader-Willi syndrome are reported. Apart from hypogonadism, hypomentia, hypotonia and obesity, they presented shorter than normal stature and the peculiar facies of this syndrome. Both twins also suffered from arterial hypertension with secondary hyperaldosteronism, an abnormality never previously recorded. The endocrinological study showed the presence of hypogonadotrophic hypogonadism in both twins. The GnRH and clomiphene tests suggested a hypothalamic disorder. Although the vast majority of cases with the Prader-Willi syndrome are isolated, the expression of this disorder in two identical twins enhances the possibility of a genetic determination.