MALIGNANT OSTEOPETROSIS - C-SRC KINASE IS NOT REDUCED IN FIBROBLASTS

Targeted disruption of the c-src gene leads to a severe form of osteop etrosis in mice [2]. As the c-src gene is expressed in all tissues and cells tested, we have analyzed fibroblasts from three individuals wit h malignant, congenital osteopetrosis for the expression of c-src at t he protein level. No differences could be detected in c-src protein an d c-src kinase activity levels between fibroblasts from healthy contro ls and affected individuals. Thus, impairment of c-src function as an etiological factor in human osteopetrosis appears unlikely in the indi viduals investigated.