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REGISTRY DATA

rettX in numbers

A transparent view of the European Rett syndrome registry — updated live from the rettX platform.

511
Patients in the registry
159
Distinct gene mutations
30+
European countries

Live from the rettX registry · updated May 16, 2026 1:03 am

Why we share these numbers

Transparency builds trust. Behind every number is a family who chose to share their story so researchers, clinicians, and decision-makers can better understand Rett syndrome across Europe. The figures shown are aggregate counts only — no individual data is ever exposed.

GEOGRAPHIC REACH

Patients by country

The registry now spans communities across Europe. Below is the current ranking of registered patients by country.

511 patients across 20 European countries

  1. Spain 144
  2. Türkiye 96
  3. Hungary 27
  4. Greece 22
  5. Portugal 21
  6. Austria 19
  7. Netherlands 18
  8. Italy 17
  9. Poland 15
  10. Germany 12
  11. Other countries 45

Live from the rettX registry · updated May 16, 2026 1:03 am

GENETIC PROFILE

Most frequent mutations

Rett syndrome is caused by mutations in the MECP2 gene. The registry tracks the specific variants present in our community, helping researchers prioritise studies on the most common mutations.

Distribution of top gene mutations in the registry Top mutations represented across 443 patients with mutation data. 443 patients with mutation data

Reference transcript: NM_004992.4 (MECP2)

Top mutations and their share of registered patients
Color Mutation Patients Share
c.502C>T p.(R168*) 51 11.5%
c.473C>T p.(T158M) 47 10.6%
c.880C>T p.(R294*) 41 9.3%
c.763C>T p.(R255*) 37 8.4%
c.916C>T p.(R306C) 34 7.7%
c.808C>T p.(R270*) 33 7.4%
c.397C>T p.(R133C) 29 6.5%
Other mutations 171 38.6%

Live from the rettX registry · updated May 16, 2026 1:03 am

DEMOGRAPHICS

Age distribution

Rett syndrome affects people of all ages. Below is the current age profile of patients in the registry, grouped in 5-year bands.

Age distribution across 511 patients with age data

Live from the rettX registry · updated May 16, 2026 1:03 am

Help these numbers grow

Every family who joins makes the European Rett syndrome registry stronger.

Join the registry