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REGISTRY DATA

rettX in numbers

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

553
Patients in the registry
171
Distinct gene mutations
30+
European countries

Live from the rettX registry · updated August 19, 2026 11:16 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.

553 patients across 21 European countries

  1. Spain 148
  2. Türkiye 96
  3. Hungary 27
  4. Austria 27
  5. Greece 22
  6. Portugal 21
  7. Netherlands 20
  8. Italy 19
  9. Czechia 17
  10. Poland 16
  11. Other countries 47

Live from the rettX registry · updated August 19, 2026 11:16 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 477 patients with mutation data. 477 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*) 53 11.1%
c.473C>T p.(T158M) 52 10.9%
c.880C>T p.(R294*) 45 9.4%
c.763C>T p.(R255*) 39 8.2%
c.916C>T p.(R306C) 36 7.5%
c.808C>T p.(R270*) 34 7.1%
c.397C>T p.(R133C) 32 6.7%
Other mutations 186 39.0%

Live from the rettX registry · updated August 19, 2026 11:16 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 553 patients with age data

Live from the rettX registry · updated August 19, 2026 11:16 am

Help these numbers grow

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

Join the registry