Syndromes: Fragile X syndrome

Series about conditions with common symptoms that constitute syndromes
Fragile X syndrome

Fragile X syndrome (FXS) is a sex-linked chromosomal abnormality, significantly associated with learning and intellectual disabilities. It is the most common inherited cause of learning/intellectual disabilities in the world.

Figures vary about the overall prevalence of FXS, but Hunter et al (2014) identified that 1 in 7,000 boys are affected while the ratio for girls is 1 in 11,000.

Although the long, narrow facial features and large ears and jawbone associated with FXS can be evident in the individual, these features are generally not present at birth and many people with FXS do not present with these facial features at all, which can prolong diagnosis.

Common characteristic

The most common characteristic of FXS is the presence of learning or intellectual disability. This can


Want to read more?

Unlock full access to RCNi Plus today

Save over 50% on your first three months:

  • Customisable clinical dashboard featuring 200+ topics
  • Unlimited online access to all 10 RCNi Journals including Learning Disability Practice
  • RCNi Learning featuring 180+ RCN accredited learning modules
  • NMC-compliant RCNi Portfolio to build evidence for revalidation
  • Personalised newsletters tailored to your interests

This article is not available as part of an institutional subscription. Why is this?