Towards an understanding of neuropsychiatric manifestations in fragile X premutation carriers

Abstract

Fragile X-associated disorders are a group of disorders caused by expansion of noncoding CGG repeat elements in the fragile X (FMR1) gene. One of these disorders, fragile X syndrome, is the most common heritable cause of intellectual disability, and is caused by large CGG repeat expansions (>200) resulting in silencing of the FMR1 gene. An increasingly recognized number of neuropsychiatric fragile X-associated disorders have recently been identified that are caused by ‘premutation’ range expansions (55–200). These disorders are characterized by a spectrum of neuropsychiatric manifestations ranging from an increased risk of neurodevelopmental, mood and anxiety disorders to neurodegenerative phenotypes, such as the fragile X-associated tremor ataxia syndrome. This article reviews the advances in the clinical understanding of neuropsychiatric disorders in premutation carriers across the lifespan and offers guidance for the detection of such disorders by practicing psychiatrists and neurologists.