Longevity in Rett syndrome: analysis of the North American Database

Abstract

Objective: To determine longevity in Rett syndrome (RTT) from a large cohort.

Study design: The North American RTT Database allows the examination of longevity in a large cohort of individuals with RTT from the United States and Canada. This database contains information on 1928 individuals, 85.5% with typical RTT, 13.4% with atypical RTT, and 1.1% with a mutation in the methyl-CpG-binding protein 2 gene (MECP2) but not RTT. Kaplan-Meier analyses were performed to assess longevity.

Results: Earlier decennial cohorts exhibited better survival than recent cohorts, with most participants surviving into middle age. Comparing overall survival in persons with typical RTT and atypical RTT revealed greater mortality in typical RTT across the observed lifespan (P < .0001). Comparing survival in persons with RTT and identified MECP2 mutations and persons with unknown MECP2 status demonstrated greater mortality in the latter group (P < .0001, log-rank test).

Conclusions: This analysis provides strong evidence for significant longevity in RTT and indicates the need for careful planning for long-term care of these women. The disproportionately greater survival seen in earlier time periods and in persons with atypical RTT may be attributed to more severely affected individuals dying before diagnosis in the former and to greater numbers with milder variants (ie, preserved speech and delayed onset) in the latter.

Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1. Survival Patterns for Rett Syndrome by Decade of Birth

Product limit survival function is estimated for six separate epochs: 1935-1959; 1960-1969; 1970-1979; 1980-1989; 1990-1999; and 2000-2009. The resulting curves demonstrate the potential for survival into middle age.

Figure 2. Overall Survival of Atypical (2A) and Typical (2B) Rett Syndrome

Kaplan-Meier curves indicate significantly better survival for individuals with atypical versus typical Rett syndrome (Log-rank test p