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REGISTRY DATA

rettX in numbers

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

563
Patients in the registry
172
Distinct gene mutations
30+
European countries

Live from the rettX registry · updated September 18, 2026 12:27 pm

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.

563 patients across 21 European countries

  1. Spain 149
  2. Türkiye 96
  3. Austria 29
  4. Hungary 28
  5. Portugal 22
  6. Greece 22
  7. Italy 21
  8. Netherlands 20
  9. Czechia 18
  10. Poland 16
  11. Other countries 48

Live from the rettX registry · updated September 18, 2026 12:27 pm

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 483 patients with mutation data. 483 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 11.0%
c.473C>T p.(T158M) 52 10.8%
c.880C>T p.(R294*) 45 9.3%
c.763C>T p.(R255*) 40 8.3%
c.916C>T p.(R306C) 36 7.5%
c.397C>T p.(R133C) 34 7.0%
c.808C>T p.(R270*) 34 7.0%
Other mutations 189 39.1%

Live from the rettX registry · updated September 18, 2026 12:27 pm

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 563 patients with age data

Live from the rettX registry · updated September 18, 2026 12:27 pm

Help these numbers grow

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

Join the registry