Methods Twenty-one subjects with PWS aged 4-53 years underwent a low dose adrenocorticotropic hormone (ACTH) stimulation test (LDAST) (1 μg/m2, maximum 1 μg) followed by an overnight metyrapone test (OMT).
No significant differences in biochemical findings (phenylalanine, tyrosine, catecholamines, or beta-melanocyte-stimulating hormone) were found between deletion and nondeletion PLWS patients or between hypopigmented and normally pigmented patients.
Thus, a decrease in circulating plasma immunoreactive beta-MSH (LPH) does not appear to be the cause of the hypopigmentation observed in some patients with PLWS.