A patient with trisomy 13 mosaicism with an unusual skin pigmentary pattern and prolonged survival.

Trisomy 13, or Patau syndrome, is a chromosomal disorder that can occur in complete, partial, or mosaic forms. Mosaicism is observed in 6% of individuals with trisomy 13 and, in contrast to the complete form, has wide phenotypic variability, longer survival, and in some patients an unusual skin pigmentary pattern similar to phylloid hypomelanosis. We describe here a 12-year-old girl with trisomy 13 mosaicism (mos 47,XX,+13[9]/46,XX[16]) who had three major malformations, an unusual skin pigmentary pattern, and prolonged survival.