I'm glad you read my post.
I understand your concerns and I really can't get the fact how the hospital underdiagnosed him.
There is a brief period of time where children may tip-toe intermittently, and it would be considered normal for that brief period of time right when children first start to walk up until maybe just after 2 years of age. After that, it is no longer considered normal to walk on tip-toes bilaterally.
Did he start tip-toeing within three months of the initial onset of walking or later?
Is he doing that occasionally, on and off, when he is cruising around, especially if he is walking on a bare floor or he constantly walks on his tip-toes and find difficult or impossible to walk flat-footed without help?
Is there a family history of tip-toeing?
Does you son have a dry skin and sparse hair?
Have you noticed a soft protrusion around his navel?
Best wishes for you and your family!
Marija