Rett's syndrome

This code represents a rare, severe neurodevelopmental disorder affecting primarily females, characterized by normal early development followed by regression in language and motor skills. It leads to distinctive hand movements, microcephaly, seizures, and intellectual disability.

Assign this code for documented diagnoses of Rett's syndrome, typically identified through clinical presentation and genetic testing (MECP2 gene mutation). Documentation should clearly indicate the characteristic developmental regression and neurological features consistent with the syndrome.

• Do not code concurrently with other pervasive developmental disorders listed in the Excludes1 note, as these are mutually exclusive.
• Ensure documentation specifies Rett's syndrome and not a general pervasive developmental disorder.
• Sequence this code as the primary diagnosis when it is the reason for the encounter or hospitalization.