BYU Biology 9 Question: What is the cause of Patau syndrome?

Patau syndrome, also known as Trisomy 13, (named after Dr Klaus Patau, who identified the chromosomes responsible for it in 1960) is caused by an extra chromosome - chromosome number 13. It affects 1 in 3000 births, with boys and girls affected in equal numbers. Trisomy 13 is the third most common autosomal anomaly after Trisomy 21 (Down Syndrome) and Trisomy 18 (Edward's Syndrome).