Genetic testing for Rett syndrome-associated genes (eg, MECP2, FOXG1, or CDKL5) may be considered medically necessary to establish a genetic diagnosis of Rett syndrome in a child with developmental delay and signs/symptoms of Rett syndrome, when a definitive diagnosis cannot be made without genetic testing.
Targeted genetic testing for a known familial Rett syndrome-associated variant may be considered medically necessary to determine carrier status of first-degree female relatives (a mother or a sister) of an individual with Rett syndrome.
All other indications for genetic testing for Rett syndrome-associated genes (eg, MECP2, FOXG1, or CDKL5), including routine carrier testing (preconception or prenatal) in persons with negative family history, and testing of asymptomatic family members to determine future risk of disease, are considered investigational.
