CLINICAL, MORPHOLOGIC, AND BIOCHEMICAL CHARACTERISTICS OF CHEDIAK-HIGASHI-SYNDROME IN 56 JAPANESE BLACK CATTLE

Objective-To characterize Chediak-Higashi syndrome (C-HS) in Japanese Black cattle. Animals-56 of 200 cattle with a bleeding disorder and gi ant granules in leukocytes. Procedure-Ciinical observation, CBC, hemos tatic screening test, platelet aggregometry, electron microscopy, plat elet constituent analysis, and ophthalmoscopic examination were done. Results-Affected Japanese Black cattle had increased bleeding tendency and abnormal granules in their leukocytes. Susceptibility to infectio n was not increased. Cutaneous albinism was evident in 6 newborn calve s, but not in most affected cattle. In ail affected cattle, the tapeta l fundus was pale and the nontapetal fundus was almost devoid of pigme nt. By electron microscopy, a remarkable decrease in the number of den se granules in platelets was observed. Functionally, collagen-induced platelet aggregation was markedly reduced. Conclusions-This bleeding d isorder was diagnosed as C-HS. With regard to susceptibility to infect ion, albinism, and mortality, clinical manifestations of C-HS in Japan ese Black cattle were moderate, compared with C-HS in human beings and Hereford cattle. Clinical Relevance-Because an autosomal recessive mo de of inheritance was documented and recessive homozygotes could be ea sily detected, C-HS in Japanese Black cattle can be controlled.