Trisomy 12 mosaicism diagnosed at 16 weeks' amniocentesis in a 42-year
-old woman was not confirmed at 18 weeks' gestational age in amniotic
fluid or fetal blood. Fetal skin biopsy performed at the same time did
, however, allow the detection of trisomy 12 in 1 of 14 fibroblasts an
alysed. Fetal skin biopsy can be included within the diagnostic proced
ures to be performed when a level III mosaicism is found in the amniot
ic fluid.