Cockayne syndrome: clinicopathologic and tissue culture studies of affected siblings.

Two siblings with Cockayne syndrome (CS) had extremely severe and early onset cachectic dwarfism, developmental delay, cataracts, microcephaly, peripheral neuropathy, and spastic quadriplegia. In order to study the inherited DNA-repair defect known to be present in cultured CS cells, a lymphoblastoid line was established from the younger sibling. Tissue culture studies revealed the line to have a hypersensitivity to the lethal effects of 254-nm ultraviolet radiation (UV) equivalent to that of lymphoblastoid lines from CS patients who had either the usual severity or a very mild form of CS. Autopsy of the older sibling at six years of age showed the brain to be severely atrophic, with particularly severe cerebellar atrophy. There was a marked reduction in the number of granule cells in the cerebellum and irregular patchy myelination throughout the brain. Many astrocytes contained either a large, bizarre-shaped nucleus or multiple nuclei. Some Purkinje cells of the cerebellum and pyramidal neurons of the hippocampus were binucleated. It is suggested that the DNA-repair defect of CS causes abnormalities in nuclear DNA replication and cell division which result in cell death and in the observed nuclear abnormalities.