CHROMOSOME AND BLOOD MARKER STUDIES IN FAMILIES OF PATIENTS AFFECTED BY XERODERMA PIGMENTOSUM AND TRICHOTHIODYSTROPHY

Chromosome and blood marker studies were performed in the families of 4 patients in which the association of 2 rare recessive Mendelian disorders, xeroderma pigmentosum (XP-D) and trichothiodystrophy (TTD), was present. Blood genotypes did not indicate any linkage with the pathologic condition, nor any segregation anomaly. Cytogenetic analysis using high-resolution banding techniques showed a normal karyotype both in the heterozygous and in the homozygous individuals. These findings lead us to exclude a cytologically detectable chromosome rearrangement, such as microdeletion, as a possible cause of the association of XP-D and TTD in our patients.