A molecular linkage analysis of four large families with the Lowe oculocerebrorenal syndrome (LS) provided a subregional localization of LS to the distal long arm of the X chromosome at Xq24-q26. Probes from two loci that identify restriction fragment length polymorphisms (RFLPs) and map to Xq24-q26 showed no recombination with LS. A maximum likelihood recombination distance (theta) = 0.00 was obtained for DXS10 with the logarithm of the odds (lod) of 6.450. For DXS42, theta = 0.00 with a lod of 5.087. Assignment of the gene or genes for LS to Xq24-q26 has the potential of improving carrier detection and providing prenatal diagnosis in families at risk for the disease.