The first signs of<unk> -related encephalopathy are typically gross motor delays in infancy followed by developmental delays, seizure onset and language impairment. Penetrance is 100%. Mild to severe intellectual or developmental disability is present in the majority of patients. Epilepsy is present in almost all cases, with approximately 94-98% of patients affected by seizures. Truncal hypotonia and clumsy gait are typical. Behavioral and sleep problems are also common. Approximately 50% of patients receive a diagnosis of autism spectrum disorder. Some patients have significant feeding issues. Constipation has also been reported.
SYNGAP1-related intellectual disability
SYT1-associated neurodevelopmental disorder
MECP2 duplication syndrome
LMNA-related congenital muscular dystrophy
X-linked intellectual disability
X-linked spinal muscular atrophy type 2
Autosomal recessive spastic ataxia of Charlevoix-Saguenay
Foster Kennedy syndrome