1.4. Monogenetic Neurodevelopmental Disorders
Fragile X syndrome (FXS), a result of the loss-of-function of the Frmr1 gene, and Rett’s syndrome, linked to a loss of function in the Mecp2 gene, are complex neurodevelopmental disorders with some overlapping features \cite{RN38}, that both show a high co-morbidity with a diagnosis of ASD \cite{RN39,RN40,RN41,RN42}. Multiple animal models have been generated of these disorders \cite{RN40,RN44,RN43,RN45} and although these syndromes do result from single gene mutations, their endophenotypic manifestation can be complex and difficult to unravel. Nonetheless, the numerous studies which have detailed the impact of each mutation at levels ranging from synapses to behavior make them an important asset to understanding how ASD alters hippocampal function.