What is the average lifespan of someone with trisomy 13, patau syndrome?

Lifespan: In my clinical experience of 31 years practicing neonatal medicine, i would have to answer your question with a vague response. This is because each affected child does not necessarily have the same degree of affliction. The literature on this tells us that 99.9% die before a year of age. I have not seen one survive longer than two months, and I have seen many.

Trisomy 13: Patau's syndrome is a serious rare genetic disorder caused by having an additional copy of chromosome 13 in some or all of the body's cells. It's also called trisomy 13. Median survival time is 7 to 10 days.