Has anyone heard of a one-year-old not crawling or walking?

My daughter is now 12 1/2 months old and though she can sit unaided, she cannot walk, crawl or bottom shuffle. She can stand if you hold on to her, but can not pull to stand. The doctor has sent her for a barrage of blood work (which takes four weeks) to rule out a genetic or metabolic disorder. I don't encounter anyone with a baby her age who is at her level, I worry that she may be like this for life.