Rett Syndrome vs Separation Anxiety Disorder
Rett Syndrome vs Separation Anxiety Disorder in Young Children
Rett Syndrome is a rare genetic neurodevelopmental condition, usually caused by an MECP2 change and seen mostly in girls, marked by a loss of acquired skills — purposeful hand use, babble, words — and repetitive hand movements after early typical development. Separation Anxiety Disorder is an emotional condition where a fully-able child becomes intensely distressed when apart from a carer, but keeps all her skills intact. Rett involves a biological loss of abilities; separation anxiety is a strong feeling about being apart with development preserved. The key question for parents: has my child lost skills (think Rett), or is my able child overwhelmed by being apart (think separation anxiety)?
Two very different stories can look alike for a moment — one is woven into a child's genes, the other into a child's feelings — and telling them apart matters.
In short
Rett Syndrome is a rare genetic neurodevelopmental condition, almost always caused by a change in the MECP2 gene and seen mostly in girls. After a period of typical early development, a child may slow down or lose skills she had — purposeful hand use, babble or words — and develop repetitive hand movements like wringing or wave-washing. Separation Anxiety Disorder is an emotional and behavioural condition: an otherwise typically developing child becomes intensely distressed when apart from a parent or carer, but keeps all her skills, hand use and abilities intact. In short — Rett involves a loss of acquired skills and is rooted in biology; separation anxiety is a strong feeling about being apart, with development fully preserved.How they differ in everyday life
With Rett Syndrome, parents often notice a quiet regression somewhere between 6 and 18 months: a baby who was reaching, holding and babbling gradually stops, her hands begin to move in repetitive patterns, head growth may slow, and walking or coordination can change. It is present all the time — not only when a parent leaves the room — and it is a change in the child's underlying abilities, not her mood.With Separation Anxiety Disorder, the child's skills are completely intact — she plays, speaks, uses her hands and learns normally. The distress shows up around separation: crying or clinging at drop-off, worry that something bad will happen to a parent, reluctance to sleep alone, or tummy aches before school. Crucially, once reassured or reunited, she settles and is herself again. A degree of separation upset is entirely normal in toddlers; it becomes a disorder only when it is intense, lasting and gets in the way of everyday life.
The simplest distinction for a parent: Has my child lost skills she once had, with unusual hand movements (think Rett)? Or is my fully-able child overwhelmed by being apart from me (think separation anxiety)?
When to seek help
Any loss of skills a child previously had — hand use, babble, words, coordination — warrants a prompt developmental review, because regression is never something to wait out. Persistent, distressing separation worry that disrupts sleep, school or family life also deserves a gentle professional look. Either way, an early, unhurried assessment brings clarity and the right support.The Pinnacle way
This is general information, not a diagnosis — a clinical AbilityScore® and any diagnosis are formed only at a Pinnacle Blooms Network centre, under qualified clinician care, never from an app or form. Our clinicians observe how your child moves, plays, communicates and copes, then shape the right path — behavioural therapy and family support where anxiety is the picture, and developmental, communication and motor support where regression is involved. Learn more about Rett Syndrome. Backed by 2.5 billion+ data points and 25 million+ therapy sessions across 70+ centres.Trusted sources
The World Health Organization's ICD-11 frames Rett Syndrome among neurodevelopmental conditions and separation anxiety among the anxiety disorders; the American Academy of Pediatrics and HealthyChildren describe typical separation worry in young children and when it needs attention.Next step — Noticing lost skills, unusual hand movements, or distress that goes beyond ordinary clinginess? Book a developmental screening and let a clinician bring clarity.
What to watch
Watch for a child who has lost skills she once had — purposeful hand use, babble or words — alongside repetitive hand movements like wringing or washing motions (this points toward Rett and needs a prompt review). Separation anxiety instead shows a fully-able child who is intensely distressed at being apart from a parent but settles once reunited.
Try this at home
Keep a simple notebook of milestones. For separation worry, practise short, cheerful goodbyes with a clear 'I'll be back after lunch' and a small comfort object — but if your child seems to lose a skill she once had, note the date and book a review rather than waiting.
Trusted sources
Developed by SETU Consortium · Pinnacle Blooms Network · Last reviewed 2026-06-10 · reviewed every 365 days
This is general information, not a diagnosis. A clinical AbilityScore® and any diagnosis are formed only at a Pinnacle Blooms Network centre, under qualified clinician care.
Frequently asked
Can Separation Anxiety Disorder turn into Rett Syndrome?
No. They are entirely separate things. Separation Anxiety Disorder is an emotional condition in an otherwise typically developing child, while Rett Syndrome is a genetic neurodevelopmental condition usually caused by a change in the MECP2 gene. One does not become the other.
How do I tell the difference at home?
Ask yourself one question: has my child lost skills she once had — hand use, babble, words — often with repetitive hand movements? That points toward Rett and needs a prompt review. If instead she is fully able but overwhelmed only when apart from you, and settles once reunited, that suggests separation anxiety. A clinician confirms either.
Is some separation anxiety normal in young children?
Yes, very much so. Distress at being apart from a parent is a normal part of toddler development. It becomes a disorder only when it is intense, lasting and interferes with sleep, play, school or family life.
Why does Rett Syndrome mostly affect girls?
Rett Syndrome is almost always linked to a change in the MECP2 gene, which sits on the X chromosome. It is most commonly recognised in girls. Any regression or loss of skills in a child should be reviewed promptly by a clinician.