text: symptoms of sandhaus disease? need to know causes and symptoms.  the child in question is 9 months old...has very little muscle control, cannot grasp anything in hands, cannot sit up alone, does not do any of the things a baby does at this age.  a friend that has had a child with this disease told me to have the child in question parents to ask their doctor about sandhaus. primarily by bilateral hypoplastic patellae and multiple congenital skeletal anomalies not otherwise explained by other skeletal problems.