A 36-year-old North American patient has been suffering from Olmsted s
yndrome since early childhood. This rare inborn error of keratinizatio
n consists in pronounced, mutilating keratoderma of palms and soles an
d associated periorificial keratoses. The patient has now been treated
with etretinate for more than 6 years, resulting in a marked reductio
n of hyperkeratoses. Electron microscopic investigation of skin biopsi
es taken before and during therapy have confirmed the significant clin
ical improvement. Even though this retinoic acid derivative, a powerfu
l regulating agent with a de-differentiating effect, cannot cure the b
asic defect, the marked hyperproliferation of the epidermis is reduced
, so that terminal differentiation is delayed and thereby normalized.
At the same time, the synthesis of keratinization proteins, such as ke
ratins and keratohyalin, which is suppressed before therapy, increases
. The familial connective tissue disorder existing independently of Ol
msted syndrome in this patient (perhaps a mild form of Ehlers-Danlos s
yndrome) is not influenced by the retinoid therapy.