Both diseases affect many organs, which explains the different symptoms :
​
-
Craniofacial features
​
-
Skeletal features: Scoliosis (permanent deformity of the spine due to rotation of the vertebrae); joint contractures (joint stiffness) that limit daily mobility, etc.
​
-
Cutaneous features: Hyperelastic, dry and thin skin; skin fragility with delayed healing of some wounds, lipodystrophy (loss of fat), etc.
​
-
Neurological features: Brain malformations, rarely associated with intellectual disability etc.
​
Other symptoms appear to be more syndrome-specific, such as acro-osteolysis (progressive bone erosion of extremities) and brachydactyly (shortening of the fingers and toes) in PS, or tall stature, large hands and large feet in KOGS.
Complications can be seen in the course of the disease :
​
-
Skeletal complications: osteoporosis (bone fragility due to low bone density) with risk of bone fractures etc.
​
-
Neurological complications: risk of convulsions, neurological deterioration with appearance of white matter anomalies, etc.
​
-
Ocular complications: Recurrent pterygia (thickening of the conjunctiva covering the eye, sometimes leading to impaired vision).
​
-
Cardiovascular complications: Arterial aneurysm, i.e a bulge in the wall of an artery, which forms when there is a weak area in the artery wall. Untreated aneurysms can burst open, leading to internal bleeding or cause blood clots that block the flow of blood in your artery leading to a stroke. Depending on the location of the aneurysm, a rupture or clot can be life-threatening. These aneurysms can affect the arteries of the brain, heart or kidney.
This list of symptoms is not exhaustive and KOGS/PS present with some clinical variability from patient to patient. Most of the clinical signs are progressive and each appears to worsen at its own rate in the absence of medical management. As a result, this disease also carries a risk of death, a risk that this study will try to determine as accurately as possible.
