Linkage data for familial incontinentia pigmenti (IP2) and 17 X chromosomal markers are reported. The linkage previously found between IP2 and the F8C locus is confirmed (Z max = 11.85 at theta = 0.028). Linkage is established with distal markers DXS1108 (Z max = 10.06 at theta = 0.00) and DXYS154 (Z = 9.07 at theta = 0.019). Multipoint analysis supports the distal localization of the IP2 gene with respect to the F8C locus.