RTS is a multisystem disorder. EP300 is associated with RTS type 2 (RTS2).
The typical clinical presentation of RTS2 includes:
• Developmental delay and intellectual disability (ID):
Highly variable with intelligence quotient (IQ) ranging from 25 to 79.
Language delay is present in 90% of cases.
For RTS2 patients on average the cognitive level tends more towards the higher level.
• Typical facial dysmorphism:
Pronounced appearance of the nose, which has a broad root, with a long protruding septum and a long columella below the alae nasi.
Microcephaly
Bitemporal retraction
Downslanted palpebral fissures
Epicanthic folds
Arched eyebrows with long eyelashes
Ptosis of the eyelids
Strabismus
High arched palate
Low set and posteriorly rotated ears
Characteristic smiling aspect with the closure of the palpebral fissures called “grimacing smile”, especially in the newborn.
RTS2 patients can have mild facial characteristics
• Distal limb and skeletal abnormalities:
Abnormalities of the extremities are usually one of the most characteristic phenotypic elements to evoke the diagnosis
Broad thumbs/halluces
• Growth retardation
Intrauterine and postnatal growth restriction
In general moderate
• Hypertrichosis
• Maternal preeclampsia
Other less frequently reported clinical features are:
• Cardiac anomalies
• Persistent hyperinsulinemic hypoglycemia
• Non-specific EEG abnormalities
• Brain malformations: dysmorphic aspects of the corpus callosum and cerebellar vermis, periventricular posterior white matter abnormalities
• Dental abnormalities (talon cusps)
• Ocular abnormalities
• Feeding problems
• Urinary tract anomalies
• Keloid and hypertrophic scars
EP300