Two sisters with Rett syndrome.

Iwata et al. (1990) wrote a short report about two adult sisters who both have Rett syndrome.

The authors simply described what the women looked like, how they moved, and when their seizures began.

No treatment was tested; it is a plain case series meant to show doctors how the illness can vary inside one family.

Both sisters had classic hand-wringing and could not talk, yet the age when seizures started was very different.

This single pair shows that even relatives with the same gene change can follow their own timetable.

Bauman (1991) pulled together every early Rett paper and included this pair, saying such family reports help map the full picture.

Wilkinson et al. (1998) later widened the lens by describing thirty women who still had some speech, proving Rett is not one-size-fits-all.

Doughty et al. (2002) surveyed many adults and found they showed less irritability than other adults with ID, backing the idea that behavior profiles can differ even within the same diagnosis.

Together the papers trace a line: first came tiny family stories, then bigger surveys, then recognition of milder variants.

If you meet a girl who regresses after a year of normal growth, think Rett even if her cousin with Rett looks very different.

Expect seizures to start at any age and watch for small gains in eye-gaze or hand use; these details shape your communication plan and help families set realistic timelines.