How did Fragile X syndrome get its name?

Most people have 46 chromosomes (23 pairs). Our gender is determined by the X and Y chromosomes: males have one Y chromosome and one X chromosome, while females have two X chromosomes. ... The name fragile X syndrome is derived from its link to the X chromosome. read more

It's because a proportion of the X chromosomes of affected people appear under the microscope to contain breaks, when the cells are grown in folate-deficient medium: hence 'fragile' X chromosomes. I learnt this working in a hospital cytogenetics lab in Caterham Surrey, where one of the affected brothers in the original Martin-Bell paper still lived (in the mid 1980s). read more

Fragile X syndrome co-occurs with autism in many cases and is a suspected genetic cause of the autism in these cases. This finding has resulted in screening for FMR1 mutation to be considered mandatory in children diagnosed with autism. read more

If a male passes on his Y chromosome he will have a son and if he passes on his X chromosome he will have a daughter. As the FMR1 gene is on the X chromosome, males can only pass on their FMR1 gene to their daughters. The length of the FMR1 gene does not increase in size when passed from father to child. read more