Abnormal skin fibroblast cytogenetics in four dysmorphic patients with normal lymphocyte chromosomes.

Four patients with features suggestive of chromosome disorders but with normal lymphocyte karyotypes were found to have chromosome aberrations in skin fibroblast karyotypes. Although mosaicism for chromosome abnormalities in lymphocyte cultures is common, apparent restriction of mosaicism to one tissue is unusual. We suggest that after examination of lymphocyte karyotypes, certain patients warrant cytogenetic evaluation of a second tissue, usually cultured skin fibroblasts.