Trained as a child neurologist, Zoghbi could not bear the plight of children affected by devastating neurological diseases so she pursued research in hope of helping her patients. After encounters with patients with Rett syndrome—a disorder that strikes after a year of normal development and presents with developmental regression, social withdrawal, loss of hand use and compulsive wringing of the hands, seizures and a variety of neurobehavioral symptoms—she decided to find its genetic roots. The biggest challenge was that Rett syndrome is typically a sporadic disorder (one in a family) and the genome was neither mapped nor sequenced. Zoghbi’s perseverance paid off when after a 16-year search she discovered that Rett syndrome is caused by mutations in MECP2. Zoghbi revealed the importance of MeCP2 for the function of various neuronal subtypes and pinpointed the contributions of various neuronal subtypes in the brain to various neuropsychiatric features. Zoghbi also provided evidence that the brain is exquisitely sensitive to the levels of MeCP2 and that doubling MeCP2 levels causes progressive neurological deficits in mice. This disorder is now recognized as MECP2 Duplication Syndrome in humans. Her recent work showed the symptoms of adult mice modeling the duplication disorder can be reversed using antisense oligonucleotides that normalize MeCP2 levels.
The discovery of the Rett syndrome gene provided a straightforward diagnostic genetic test allowing early and accurate diagnosis of the syndrome. It also revealed that mutations in MECP2 can also cause a host of other neuropsychiatric features ranging from autism to juvenile onset schizophrenia. Further, it provided evidence that an autism spectrum disorder (ASD) or an intellectual disability disorder (IDDs) can be genetic even if it is sporadic (not inherited). Today we know that dozens of ASDs and IDDs are caused by sporadic new mutations. Moreover, her discovery opened up a new area of research on the role of epigenetics in neuropsychiatric phenotypes. Her use of an antisense oligonucleotide to lower MeCP2 levels provides a potential therapeutic strategy for the MECP2 duplication syndrome and inspires similar studies for other duplication disorders.