Localization of the X-linked retinitis pigmentosa locus between DXS7 and DXS84 in a family showing tapetal reflex in heterozygotes.

The linkage relationships between the X-linked retinitis pigmentosa (XLRP) locus and seven Xp loci: DXS14, DXS7, OTC, DXS141, DXS148, DXS84 and DXS206 were analysed in one large family in which the heterozygotes exhibited the tapetal reflex. Evidence drawn from two-point and multipoint linkage analysis and a number of triply informative crossovers suggests that the XLRP locus in this family is between DXS7 and DXS84. The putative order of loci on the short arm of the X chromosome is: centromere - DXS14 - DXS7 - OTC - XLRP/DXS141 - DXS148 - DXS84 - DXS206 - telemere.