What is Rett Syndrome?

A baby who begins as expected, then quietly loses skills already learned — that pause-and-regression pattern is what Rett syndrome describes.

In short

Rett syndrome (ICD-11 LD90.0) is a rare, genetically-driven neurodevelopmental condition seen almost entirely in girls. After an apparently typical first 6–18 months, a child shows a distinctive slowing and then a loss of purposeful hand use and spoken words, alongside the emergence of repetitive hand movements (such as wringing, washing or mouthing). It is caused in most cases by changes in the MECP2 gene — so it is a medical-genetic condition, identified by a clinician, not something parenting causes.

What this looks like in early childhood

The classic story is one of regression after an early period of typical development. Parents often notice: slowing of head growth, loss of previously-acquired hand skills, loss of babble or first words, and the appearance of constant midline hand movements that replace useful reaching and grasping. Walking may become unsteady or be lost, and some children show breathing irregularities, teeth-grinding or periods of unsettled mood. Because it can be confused with autism in the regression phase, a careful clinical and genetic evaluation is what distinguishes it.

Rett syndrome is recognised through a clinical genetics and neurology pathway — the priority when regression is suspected is prompt medical and genetic referral, not therapy alone. Therapy then plays a vital, lifelong role in protecting communication, movement, hand function and quality of life.

The Pinnacle way

This is general information, not a diagnosis — a clinical AbilityScore®, a clinician-administered structured assessment, and any diagnosis are formed only at a Pinnacle Blooms Network centre under qualified clinician care, alongside the medical and genetic team. For children with confirmed Rett syndrome, our therapists build individualised support spanning communication, motor and daily-living goals, including occupational therapy to protect hand function and engagement.

Trusted sources

WHO ICD-11 (neurodevelopmental disorders, code LD90.0); paediatric guidance from the American Academy of Pediatrics and HealthyChildren.org on developmental regression and when to seek review.

Next step — If your child has lost hand skills or words they once had, book a developmental review now so we can route you promptly to combined medical, genetic and therapy care.