165 Pili Annulati: Exclusion from candidate areas.

Jack Green1,3, David de Berker2, Elizabeth Fitzpatrick3, Susan Forrest3, Rod Sinclair1. 1Department of Dermatology, St.Vincent’s Hospital, Melbourne, Australia; 2Bristol Royal Infirmary, Bristol, England; 3Murdoch Childrens Research Institute, Melbourne, Australia

The purpose of this study was to investigate whether pili annulati is linked to keratin loci on chromosome 12 and 17 and the hairless / Marie Unna locus on chromosome 8p21. Twenty five individuals from two families after being examined and having hair taken for microscopy to establish phenotype had genomic DNA extracted. Microsatellite markers in the above areas were examined using gammaP33 labelled forward primers. Nine of eighteen individuals from one family and three of seven individuals from a second family had pili annulati. Linkage analysis of markers D17S855 and D17S1818 at è = 0.05 gave LOD scores of –0.43 and -3.86; markers D12S90 and D12S361gave LOD scores of –1.20 and –2.57; and markers D8S560 and D8S298 gave LOD scores of –3.11 and –2.16. Assuming no locus heterogeneity in these families these results suggest that a genetic susceptibility locus is unlikely to be present in these candidate areas.