What is the mode of inheiritance for edward's syndrome?

Chromosomal: Edwards syndrome is usually due to trisomy 18 (extra copy of chromosome #18) that is an accidental occurrence with low recurrence risk (<1%) to the parents. Occasionally a translocation is found and the parents need testing to see if they have a balanced translocation (no symptoms) with higher recurrence risk.

Varies: Edward's syndrome, trisomy 18, occurs when the baby has three copies of chromosome18. If three full copies so 47 chromosomes, recurrence is less than 1percent. Some babies, however, have a normal number of chromosomes but an extra 18 because of a translocation (a piece of 18 traded with another chromosome and led to trisomy) The recurrence risk is higher and both parents will be tested .