MOSAICISM IN TRISOMY-8 - PHENOTYPE DIFFERENCES ACCORDING TO TISSULAR REPARTITION OF NORMAL AND TRISOMIC CLONES

Three new observations of trisomy 8 mosaicism are presented. In two po stnatal cases, both patients showed agenesis of corpus callosum associ ated with different clinical findings. In a third case, the prenatal d iagnosis revealed trisomy 8 mosaicism exclusively in chorionic villi ( CV) cells long term culture, Normal results were obtained in CV direct preparation and in cultured amniotic cells. In lymphocytes, the child showed low level trisomy 8 mosaicism, The only clinical findings were deep palmar and plantar furrows. The present cases as well as reports in the literature indicate that the variation in tissular repartition of normal and trisomic clones in trisomy 8 mosaicism is possibly resp onsable for the missing correlation between cytogenetic findings and c linical severity in this syndrome.