Which syndrome is caused by a third copy of all or part of chromosome 18?

My son Richard was trisomy 18. He lived for 16 months. He was beautiful and he was my greatest teacher. Xo

Cloud, I am very sad for you and your husband. But you call him "your greatest teacher". I rejoice with you in that. God bless and comfort you.

I can feel in your words that you loved your son greatly. Many blessings.