Schinzel-Giedion syndrome (SGS) is a severe multi-organ disorder. It is a very rare disorder and the exact prevalence is unknown. SGS is caused by a de novo mutation in the SETBP1 gene and occurs in people with no history of the disorder in the family.
Sometimes kidney anomalies or a large tongue may have been noted on ultrasound before birth. But in the majority, SGS is diagnosed after birth or during infancy. Individuals often have several serious health problems including various congenital anomalies, severe developmental delay and a recognisable facial appearance.
Individuals show severe psychomotor delay and may show signs of spasticity. Sensorineural deafness and cerebral blindness are present in the majority. Almost all common types of epilepsy occur and is often characterised by intractable seizures. Structural brain anomalies are variable and include corpus callosum hypoplasia, cortical atrophy, ventricle anomalies, abnormal gyration and delayed mylination and choroid plexus cysts.
Urogenital anomalies are common. Hydronephrosis and underdeveloped genitalia are present in the majority. Other renal anomalies include ureter anomalies, cysts and stones.
Half of the individuals show a cardiac anomaly, the majority of which present with atrial septum defects.
Several internal organ anomalies such as pancreas hypoplasia and hepatosplenomegaly have been reported. Difficulties in swallowing and breathing are due to anomalies in the respiratory tract and an excessive presence of mucus.
Facial features are characterised by a prominent forehead, large fontanelles, midface retraction, a crease under the eyes, a short upturned nose, a wide mouth with a large tongue and, ear malformations. Other physical characteristics may include an inability to secrete tears (alacrima), hypertrichosis (excessive hair), polydactyly and cutis marmorata. On X-rays a sclerotic base of the skull, a wide occipital synchondrosis, broad ribs and some other minor features may be noted.
Children with SGS also have an increased risk to develop (mainly) neuroepithelial tumors. These can occur before birth, during infancy or childhood. Treatment is based upon decreasing the symptoms as much as possible. The majority of children do not survive past childhood due to complications of aforementioned serious health problems.