Fragile X syndrome (FXS) is one of the most common reasons for intellectual disability (ID). First described in the 1940s, it took many years to understand the disease. The awe-inspiring breakthroughs in both science and technology facilitated the recognition of the unique inheritance pattern and the genetic mechanism of fragile X. In this chapter we describe the history and evolution of our understanding of FXS as mirrored by advances in genetics.
Keywords: Anticipation; Bell J; Clinical features of FXS; FMR1 gene; Fragile X-associated tremor/ataxia syndrome; Inheritance pattern; Lubs HA; Martin JP; Premutation; Prenatal diagnosis; Primary ovarian insufficiency; Sherman paradox; Testing for fragile X syndrome; Trinucleotide repeats expansions.