3.Central nervous system issues
Intellectual disability in patients with Down syndrome is moderate or severe. The IQ ranges between 2 and 85, with a mean IQ of 50. Beyond their cognitive abilities, their bodies are also affected by nervous system alterations. Their muscles are hypotonic; they do not have proper muscle tone because the nervous system is not functioning correctly. They often have sleep apnea and sometimes insomnia and other sleeping problems. Up to 10% of these patients have recurrent seizures or at least spasmodic movements.