Molecular genetics of the Hermansky-Pudlak and Chediak-Higashi syndromes.

Hermansky-Pudlak syndrome(HPS) and Chediak-Higashi syndrome(CHS) are similar but distinct autosomal recessive genetic diseases in which a bleeding diathesis resulting from platelet storage pool deficiency is accompanied by deficient pigmentation of the skin and hair and various systemic abnormalities associated with defective lysosomal function. The diverse multi-systemic manifestations of HPS and CHS are associated with abnormalities of a number of different cytoplasmic organelles--platelet dense granules, melanosomes, lysosomes and various cytoplasmic secretory granules. Though rare, HPS and CHS probably represent just the first of what will eventually be a novel class of genetic disorders resulting from defective biogenesis, structure or function of these organelles. The genes responsible for HPS and CHS have recently been identified and are beginning to yield insights into the molecular genetics and cellular pathophysiology of these intriguing disorders.