Although physical problems do not predominate in this syndrome, there are certainly impactful limitations.
The following physical limitations may occur:
Most individuals with Chung-Jansen syndrome are overweight or obese. It is currently not clear why this happens. There might be a relation between the PHIP protein and the leptin-melanocortin pathway which is important for satiety and energy balance. Additionally, it could also be caused by side effects of medication use.
Low muscle tone (hypotonia)
In infancy, it quickly becomes clear that certain milestones are achieved later than the average child. For example, not being able to lift the neck properly in the prone position, having difficulty rolling over, sitting, crawling, standing and walking. Once the child is able to walk, the gross motor skills will remain a challenge as children often have a stiff walking pattern and fatigue easily. Typically, major milestones like cycling and swimming will be achieved later.
There is often an abnormality of the eyes. This includes strabismus, poor vision and cataract. Children often wear glasses and because of a lazy eye, an eye patch can be advised.
Another common problem is constipation. The bowels work slower, making it difficult for many children to go to the toilet and becoming toilet trained is more difficult.
Some children are born with an abnormality of the hip, which is called hip dysplasia. Often the femoral head and socket is not properly formed and a spreader pants or surgery is needed to position the hip properly. Due to the low muscle tone, there is a risk of scoliosis as children grow older. This involves a sideways curvature of the spine.
Several individuals have hypermobility of the joints which can cause pain and increase fatigue.
Abnormality and problems with the kidneys
Urinary tract infections frequently occur in young children. Some individuals have congenital abnormalities of the kidneys such as a horseshoe kidney, where the kidneys have grown together or a person is born with one kidney. Other problems that can occur are: high concentration of calcium in the urine, kidney stones, swelling of the kidney due to accumulation of urine.