[The Lyon effect of the lens: findings in the carriers of X chromosome-linked cataract and in Lowe syndrome].

In carrier women for X-linked diseases the random X-inactivation and the subsequent embryonic process of development and differentiation induce characteristic patterns of tissue mosaicism. In the lens, the random mosaic pattern of equatorial epithelial cells and their proliferation oriented toward the posterior pole induce a radial or segmental distribution pattern of clonal cell populations. This can be shown in carrier women for X-linked cataracts. Findings in a carrier woman for X-linked cataract and for Lowe's syndrome respectively are reported.